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1.
Dis Esophagus ; 23(4): 316-23, 2010 May.
Article in English | MEDLINE | ID: mdl-19788436

ABSTRACT

Randomized trials of chemoradiation for esophageal cancer have included very few patients age > or = 75. In this retrospective study, we describe the outcomes and toxicity of full-dose chemoradiation in elderly patients with esophageal cancer. Patients, age > or = 75, treated with full-dose chemoradiation for esophageal carcinoma from 2002 to 2008 were retrospectively reviewed. Thirty-four patients were identified with a median age of 79.5 (range 75-89). The median Eastern Cooperative Oncology Group performance status was 1 (range 0-3) and the median Adult Comorbidity Evaluation-27 score was 1 (range 0-3). Twenty-eight patients received definitive and six received neoadjuvant chemoradiation. The median radiation dose delivered was 50.4 Gray (range 3.6-68.4 Gray). Platinum-based chemotherapy was used in 79.4% of patients. Fifty percent of the patients completed all planned radiation therapy (RT) and chemotherapy; 85.3% completed RT. Acute toxicity > or = grade 4 occurred in 38.2% of patients, and 70.6% of the patients required hospitalization, emergency department visit, and/or RT break. Median follow-up was 14.5 months among 7 survivors, and median survival was 12.0 months (95% confidence interval [CI]: 9.7 to 24.1 months). The actuarial overall survival at 2 years was 29.7% (95% CI: 16.6 to 52.6%). There were four treatment-related deaths. The median time to any recurrence was 10.4 months. Nineteen patients had a local and/or distant recurrence. In conclusion, elderly patients experienced substantial morbidity from chemoradiation, and long-term survival was low. Future efforts to improve treatment tolerability in the elderly are needed.


Subject(s)
Esophageal Neoplasms/drug therapy , Esophageal Neoplasms/radiotherapy , Aged , Aged, 80 and over , Combined Modality Therapy , Female , Humans , Male , Radiation Dosage , Radiotherapy/adverse effects , Retrospective Studies
2.
Int J Radiat Oncol Biol Phys ; 51(1): 131-7, 2001 Sep 01.
Article in English | MEDLINE | ID: mdl-11516862

ABSTRACT

PURPOSE: The role of dose escalation with proton/photon radiotherapy in lower-grade gliomas was assessed in a prospective Phase I/II trial. We report the results in terms of local control, toxicity, and survival. MATERIALS AND METHODS: Twenty patients with Grade 2/4 (n = 7) and Grade 3/4 (n = 13) gliomas according to the Daumas-Duport classification were treated on a prospective institutional protocol at Massachusetts General Hospital/Harvard Cyclotron Laboratory between 1993 and 1996. Doses prescribed to the target volumes were 68.2 cobalt Gray equivalent (CGE, 1 proton Gray = 1.1 CGE) to gross tumor in Grade 2 lesions and 79.7 CGE in Grade 3 lesions. Fractionation was conventional, with 1.8 to 1.92 CGE once per day. Eligibility criteria included age between 18 and 70 years, biopsy-proven Daumas-Duport Grade 2/4 or 3/4 malignant glioma, Karnofsky performance score of 70 or greater, and supratentorial tumor. Median age of the patient population at diagnosis was 35.9 years (range 19-49). Ten tumors were mixed gliomas, one an oligodendroglioma. RESULTS: Five patients underwent biopsy, 12 a subtotal resection, and 3 a gross total resection. Median interval from surgery to first radiation treatment was 2.9 months. Actuarial 5-year survival rate for Grade 2 lesions was 71% as calculated from diagnosis (median survival not yet reached); actuarial 5-year survival for Grade 3 lesions was 23% (median 29 months). Median follow-up is 61 months and 55 months for 4 patients alive with Grade 2 and 3 patients alive with Grade 3 lesions, respectively. Three patients with Grade 2 lesions died from tumor recurrence, whereas 2 of the 4 survivors have evidence of radiation necrosis. Eight of 10 patients who have died with Grade 3 lesions died from tumor recurrence, 1 from pulmonary embolus, and 1 most likely from radiation necrosis. One of 3 survivors in this group has evidence of radiation necrosis. CONCLUSION: Tumor recurrence was neither prevented nor noticeably delayed in our patients relative to published series on photon irradiation. Dose escalation using this fractionation scheme and total dose delivered failed to improve outcome for patients with Grade 2 and 3 gliomas.


Subject(s)
Brain Neoplasms/radiotherapy , Glioma/radiotherapy , Photons/therapeutic use , Proton Therapy , Adult , Brain Neoplasms/mortality , Brain Neoplasms/pathology , Female , Glioma/mortality , Glioma/pathology , Humans , Male , Middle Aged , Neoplasm Recurrence, Local/diagnosis , Prospective Studies , Quality of Life , Radiotherapy Dosage , Supratentorial Neoplasms/mortality , Supratentorial Neoplasms/pathology , Supratentorial Neoplasms/radiotherapy , Survival Analysis
3.
Int J Radiat Oncol Biol Phys ; 50(2): 367-75, 2001 Jun 01.
Article in English | MEDLINE | ID: mdl-11380223

ABSTRACT

PURPOSE: To evaluate our policy of performing neck dissection based on regional response after definitive radiotherapy in patients with supraglottic carcinoma and to identify the prognostic factors in this group of patients. METHODS AND MATERIALS: Between 1970 and 1995, 121 patients with node-positive squamous cell carcinoma of the supraglottic larynx were treated with definitive radiotherapy. Sixty-nine percent of patients presented with 1997 AJCC Stage IV disease. The N-stage distribution was N1, 49; N2, 62; and N3, 10. The median size of the lymph nodes was 3 cm (range, 0.5-8 cm). Forty-five patients received once-a-day treatment with a median total dose of 65 Gy (range, 58.0-70.8 Gy) in 1.8-2.0 Gy per fraction over 48 days, and 76 patients received split-course accelerated hyperfractionation with a median total dose of 67.2 Gy (range, 63.2-73.6 Gy) in 1.6 Gy twice a day over 43 days. Patients whose lymph nodes were not clinically detectable at 4-6 weeks after the completion of radiotherapy (complete response) were followed without any neck dissection. Patients with persistent neck adenopathy (partial response) underwent neck dissection whenever possible. Mean follow-up of the living patients was 6.5 years. RESULTS: Regional response was related to the size of lymph nodes at presentation. Eighty-seven percent of patients with nodal size of 3 cm or less had a complete response, whereas 43% of patients with nodal size greater than 3 cm had a partial response. The rate of regional control at 3 years for all patients in the study was 66%. The 3-year ultimate regional control rate after salvage neck dissection was 75%. A relapse in both the primary and regional sites was the most common pattern of relapse, accounting for 39% of all the failures. Local failure was associated with subsequent regional relapse with a relative risk of 4.3. For patients with complete response in whom postradiotherapy neck dissection was withheld, the regional control rates were 75% and 86% for N1 and N2, respectively. The rate of isolated regional relapse in this group of patients was 7.5%. In multivariate analysis, significant favorable factors predictive for regional control were female gender, accelerated hyperfractionation, and complete response; whereas factors predictive for overall survival were Karnofsky Performance Scale score and regional response. The rate of Radiation Therapy Oncology Group (RTOG) Grade 2 or 3 neck fibrosis was 17% and 23% for patients with and without postradiotherapy neck dissection, respectively. CONCLUSION: Isolated regional relapse is not common in patients with supraglottic carcinoma when a complete response is achieved at 4-6 weeks after definitive radiotherapy and postradiotherapy neck dissection is not performed. Female gender, accelerated hyperfractionation, and complete response are favorable predictors of regional control.


Subject(s)
Carcinoma, Squamous Cell/radiotherapy , Carcinoma, Squamous Cell/surgery , Laryngeal Neoplasms/radiotherapy , Laryngeal Neoplasms/surgery , Adult , Aged , Aged, 80 and over , Carcinoma, Squamous Cell/pathology , Combined Modality Therapy , Dose Fractionation, Radiation , Female , Follow-Up Studies , Glottis , Humans , Laryngeal Neoplasms/pathology , Lymph Nodes/pathology , Male , Middle Aged , Neck Dissection/adverse effects , Neoplasm Recurrence, Local , Neoplasm Staging , Prognosis , Proportional Hazards Models , Radiotherapy/adverse effects , Sex Factors
4.
Int J Radiat Oncol Biol Phys ; 50(1): 127-31, 2001 May 01.
Article in English | MEDLINE | ID: mdl-11316555

ABSTRACT

PURPOSE: This study assesses the long-term outcome of patients with retroperitoneal sarcoma treated by preoperative external beam radiotherapy, resection, and intraoperative electron beam radiation (IOERT). METHODS AND MATERIALS: From 1980 to 1996, 37 patients were treated with curative intent for primary or recurrent retroperitoneal soft tissue sarcoma. All patients underwent external beam radiotherapy with a median dose of 45 Gy. This was followed by laparotomy, resection, and IOERT, if feasible. Twenty patients received 10-20 Gy of IOERT with 9-15 MeV electrons. These patients were compared to a group of 17 patients receiving preoperative irradiation without IOERT. RESULTS: The 5-yr actuarial overall survival (OS), disease-free survival, local control (LC), and freedom from distant disease of all 37 patients was 50%, 38%, 59%, and 54%, respectively. After preoperative irradiation, 29 patients (78%) underwent gross total resection. For 16 patients undergoing gross total resection and IOERT, OS and LC were 74% and 83%, respectively. In contrast, these results were less satisfactory for 13 patients undergoing gross total resection without IOERT. For these patients, OS and LC were 30% and 61%, respectively. Four patients experienced treatment-related morbidity. CONCLUSIONS: In selected patients, IOERT results in excellent local control and disease-free survival with acceptable morbidity.


Subject(s)
Retroperitoneal Neoplasms/radiotherapy , Sarcoma/radiotherapy , Soft Tissue Neoplasms/radiotherapy , Adolescent , Adult , Aged , Aged, 80 and over , Child , Combined Modality Therapy , Disease-Free Survival , Electrons , Female , Humans , Intraoperative Care , Male , Middle Aged , Radiotherapy/adverse effects , Retroperitoneal Neoplasms/surgery , Sarcoma/surgery , Soft Tissue Neoplasms/surgery , Survival Rate , Treatment Outcome
5.
Radiother Oncol ; 58(1): 83-7, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11165686

ABSTRACT

BACKGROUND AND PURPOSE: To update and summarize the experience at the Massachusetts General Hospital of a treatment program of high-dose preoperative irradiation, surgical re-resection, and intraoperative radiation therapy (IORT) as a salvage treatment for patients with recurrent rectal or rectosigmoid carcinoma. PATIENTS AND METHODS: From June 1978 to February 1997, the records of 69 patients with locally recurrent rectal carcinomas or rectosigmoid carcinomas without metastases referred for consideration of IORT were reviewed. Forty-nine patients received IORT and local control and disease-free survival curves were calculated using the actuarial method of Kaplan-Meier. RESULTS: The 5-year overall survival, local control and disease-free survival rates of 49 patients receiving IORT were 27, 35, and 20%, respectively. Thirty-four patients who underwent a macroscopic complete resection had a significantly better 5-year overall survival than the remaining 15 patients with gross residual disease (33 vs. 13%, P=0.05, log rank). For those patients, local control and disease-free survival rates were 46 and 27%, respectively. Patients with a microscopic complete resection had a superior 5-year overall survival than partially resected patients (40 vs. 14%, P=0.0001, log rank). Chemotherapy had no significant influence on overall or disease-free survival. CONCLUSION: The current analysis shows the importance of a microscopic complete resection in a multi-modality approach with IORT for survival and local control. Salvage is rare for patients undergoing subtotal resection.


Subject(s)
Adenocarcinoma/radiotherapy , Neoplasm Recurrence, Local/radiotherapy , Rectal Neoplasms/radiotherapy , Sigmoid Neoplasms/radiotherapy , Adenocarcinoma/drug therapy , Adenocarcinoma/pathology , Adenocarcinoma/surgery , Antimetabolites, Antineoplastic/therapeutic use , Combined Modality Therapy , Disease-Free Survival , Dose-Response Relationship, Radiation , Fluorouracil/therapeutic use , Humans , Intraoperative Care , Neoplasm Recurrence, Local/drug therapy , Neoplasm Recurrence, Local/pathology , Neoplasm Recurrence, Local/surgery , Neoplasm Staging , Preoperative Care , Rectal Neoplasms/drug therapy , Rectal Neoplasms/pathology , Rectal Neoplasms/surgery , Salvage Therapy , Sigmoid Neoplasms/drug therapy , Sigmoid Neoplasms/pathology , Sigmoid Neoplasms/surgery
6.
Cancer Res ; 60(19): 5565-70, 2000 Oct 01.
Article in English | MEDLINE | ID: mdl-11034104

ABSTRACT

Recent studies in experimental animals have shown that combining antiangiogenic therapy with radiation can enhance tumor response. Whether this enhancement is mainly attributable to angiogenesis inhibition, endothelial cell radiosensitivity, tumor cell apoptosis, or a decrease in the number of hypoxic cells (improved oxygenation) is not known. We designed this study to discern the role of tumor oxygenation. We chose an anti-vascular endothelial growth factor (anti-VEGF) monoclonal antibody (mAb) which has a known target, human VEGF. We also measured interstitial fluid pressure (IFP) to test the hypothesis that the decreased vascular permeability induced by the anti-VEGF mAb can lower IFP. The effect of anti-VEGF mAb on vascular density, partial oxygen tension (pO2), and apoptosis was also measured. Athymic NCr/Sed nu/nu mice bearing 6-mm xenograft of the human glioblastoma multiforme (U87), or colon adenocarcinoma (LS174T) were treated with anti-VEGF mAb injected i.p. on alternate days for a total of six injections at a dosage of 100 microg/injection/mouse. For combined anti-VEGF and radiation, single radiation doses were given under normal blood flow (20 and 30 Gy) or clamped hypoxic conditions (30 and 40 Gy) 24 h after the sixth injection of mAb. The inhibition of the growth of U87 and LS174T tumors by the anti-VEGF mAb was associated with a significant reduction in tumor vascular density and a relatively small increase in the number of apoptotic cells. Compared with size-matched controls, IFP decreased by 74% in LS174T, and 73% in U87 in mice treated with anti-VEGF mAb. After antibody treatment PO2 increased significantly in U87, but did not change in LS174T tumors. Combined treatment induced in U87 tumors a tumor-growth delay (TGD) which was greater than additive; in LS174T except for the 40-Gy hypoxic group, the effect was only additive. In both U87 and LS174T the TGD induced by the antibody was independent of oxygen levels in the tumor at the time of radiation. The fact that the increase in TGD occurred under both normoxic and hypoxic conditions suggests that anti-VEGF mAb treatment can compensate for the resistance to radiation induced by hypoxia.


Subject(s)
Adenocarcinoma/therapy , Antibodies, Monoclonal/pharmacology , Colonic Neoplasms/therapy , Endothelial Growth Factors/immunology , Glioblastoma/therapy , Lymphokines/immunology , Oxygen/metabolism , Adenocarcinoma/blood supply , Adenocarcinoma/metabolism , Animals , Antibodies, Monoclonal/immunology , Apoptosis/drug effects , Cell Division/drug effects , Cell Division/radiation effects , Cell Hypoxia , Colonic Neoplasms/blood supply , Colonic Neoplasms/metabolism , Combined Modality Therapy , Endothelial Growth Factors/antagonists & inhibitors , Endothelial Growth Factors/metabolism , Extracellular Space/physiology , Glioblastoma/blood supply , Glioblastoma/metabolism , Humans , Lymphokines/antagonists & inhibitors , Lymphokines/metabolism , Male , Mice , Mice, Nude , Partial Pressure , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors , Xenograft Model Antitumor Assays
7.
Neurosurgery ; 47(3): 623-31; discussion 631-2, 2000 Sep.
Article in English | MEDLINE | ID: mdl-10981749

ABSTRACT

OBJECTIVE: To determine the patterns of relapse and the prognostic factors for adult medulloblastomas treated in the magnetic resonance imaging era. METHODS: Between 1986 and 1996, 32 adult patients (age, > or =16 yr) with medulloblastomas confined to the craniospinal axis were treated in our institutions. Twenty cases involved classic histological features and 12 involved the desmoplastic variant. The Chang staging distribution was as follows: T1, 2; T2, 17; T3, 10; T4, 3; M0, 24; M1, 1; M2, 4; M3, 3. Brainstem invasion was present in nine patients. Lesions were midline in 13 cases and lateral in 19. Resection was complete in 17 cases, subtotal in 6, and partial in 5, with biopsy only in 4 cases. All patients received postoperative radiotherapy, with median doses of 36 Gy to the entire craniospinal axis and 55 Gy to the posterior fossa. Twenty-four patients received chemotherapy (20 before radiotherapy, 3 after radiotherapy, and 1 before and after radiotherapy). RESULTS: With a median follow-up period of 5.4 years, 17 patients experienced recurrences. At 5 and 8 years, overall survival rates were 83 and 45% and disease-free survival rates were 57 and 40%, respectively. The 5- and 8-year posterior fossa control rates were 67 and 59%, respectively. Twenty-nine percent of all relapses occurred more than 5 years after treatment. The posterior fossa was the most common site of relapses. In univariate analyses, factors adversely affecting posterior fossa control were less than complete resection (P<0.001), the presence of brainstem invasion (P = 0.02), and the use of chemotherapy (P = 0.03). The overall radiotherapy duration was marginally significant in predicting posterior fossa control, with 5-year posterior fossa control rates of 81 and 49% for durations of less than 48 days and 48 days or more, respectively (P = 0.06). In a multivariate analysis, complete resection was predictive of improved posterior fossa control (P = 0.02) and disease-free survival (P = 0.02) rates. Of the eight low-risk patients who received radiotherapy alone, three experienced recurrences in the bone as the only site of relapse. CONCLUSION: Late relapse is common among adult patients with medulloblastomas, and long-term follow-up monitoring is important. Because of the high risk of systemic failure among the low-risk patients treated with radiotherapy alone, the role of chemotherapy for this group of patients needs to be further investigated. Complete resection, the absence of brainstem invasion, and an overall radiotherapy duration of less than 48 days are important prognostic factors.


Subject(s)
Cerebellar Neoplasms/surgery , Medulloblastoma/surgery , Adolescent , Adult , Cerebellar Neoplasms/mortality , Cerebellar Neoplasms/pathology , Cerebellum/pathology , Cerebellum/surgery , Combined Modality Therapy , Female , Humans , Male , Medulloblastoma/mortality , Medulloblastoma/pathology , Middle Aged , Neoadjuvant Therapy , Neoplasm Recurrence, Local/mortality , Neoplasm Recurrence, Local/pathology , Neoplasm Recurrence, Local/surgery , Neoplasm Staging , Prognosis , Salvage Therapy , Survival Rate
8.
Ann Surg ; 230(1): 49-54, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10400036

ABSTRACT

OBJECTIVE: The long-term outcomes of patients undergoing local excision with or without pelvic irradiation were examined to define the role of adjuvant irradiation after local excision of T1 and T2 rectal cancers. METHODS: Ninety-nine patients with T1 or T2 rectal cancers underwent local excision with or without adjuvant irradiation at Massachusetts General Hospital and Emory University Hospital between January 1966 and January 1997. Of these, 52 patients were treated by local excision alone and 47 patients by local excision plus adjuvant irradiation. Twenty-six of these 47 patients were treated by irradiation in combination with 5-fluorouracil chemotherapy. The outcomes of these groups were compared. RESULTS: The 5-year actuarial local control and recurrence-free survival rates were 72% and 66%, respectively, for the local excision alone group and 90% and 74%, respectively, for the adjuvant irradiation group. This improvement in outcome was evident despite the presence of a higher-risk patient population in the adjuvant irradiation group. Adverse pathologic features such as poorly differentiated histology and lymphatic or blood vessel invasion decreased local control and recurrence-free survival rates in the local excision only group. Adjuvant irradiation significantly improved 5-year outcomes in patients with high-risk pathologic features. Four cases of late local recurrence were seen at 64, 72, 86, and 91 months in the adjuvant irradiation group. CONCLUSIONS: The authors recommend adjuvant chemoradiation for all patients undergoing local excision for T2 tumors, and for T1 tumors with high-risk pathologic features. The four cases of late local failures beyond 5 years in the adjuvant irradiation group underscores the need for careful long-term follow-up in these patients.


Subject(s)
Rectal Neoplasms/radiotherapy , Rectal Neoplasms/surgery , Actuarial Analysis , Adult , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Male , Middle Aged , Neoplasm Staging , Radiotherapy, Adjuvant , Rectal Neoplasms/mortality , Rectal Neoplasms/pathology , Survival Rate , Time Factors
9.
J Clin Epidemiol ; 52(3): 259-71, 1999 Mar.
Article in English | MEDLINE | ID: mdl-10210244

ABSTRACT

A recent national panel on cost-effectiveness in health and medicine has recommended that cost-effectiveness analysis (CEA) of randomized controlled trials (RCTs) should reflect the effect of treatments on long-term outcomes. Because the follow-up period of RCTs tends to be relatively short, long-term implications of treatments must be assessed using other sources. We used a comprehensive simulation model of the natural history of stroke to estimate long-term outcomes after a hypothetical RCT of an acute stroke treatment. The RCT generates estimates of short-term quality-adjusted survival and cost and also the pattern of disability at the conclusion of follow-up. The simulation model incorporates the effect of disability on long-term outcomes, thus supporting a comprehensive CEA. Treatments that produce relatively modest improvements in the pattern of outcomes after ischemic stroke are likely to be cost-effective. This conclusion was robust to modifying the assumptions underlying the analysis. More effective treatments in the acute phase immediately following stroke would generate significant public health benefits, even if these treatments have a high price and result in relatively small reductions in disability. Simulation-based modeling can provide the critical link between a treatment's short-term effects and its long-term implications and can thus support comprehensive CEA.


Subject(s)
Brain Ischemia/economics , Brain Ischemia/epidemiology , Decision Support Techniques , Randomized Controlled Trials as Topic/statistics & numerical data , Acute Disease , Brain Ischemia/therapy , Computer Simulation , Cost-Benefit Analysis/statistics & numerical data , Disability Evaluation , Humans , Models, Economic , Monte Carlo Method , Outcome Assessment, Health Care , Quality-Adjusted Life Years , Randomized Controlled Trials as Topic/economics , Risk Factors , Sensitivity and Specificity , Survival Analysis , Treatment Outcome , United States/epidemiology
10.
Dis Colon Rectum ; 42(2): 167-73, 1999 Feb.
Article in English | MEDLINE | ID: mdl-10211491

ABSTRACT

PURPOSE: To further define the indications for postoperative pelvic irradiation and chemotherapy, an analysis of the influence of extent of tumor invasion into perirectal fat, lymphatic or venous vessel invasion, and tumor grade on the clinical course of patients with Stage T3N0 rectal cancer undergoing surgery was undertaken. METHODS: From 1968 to 1985, 117 patients with Stage T3N0 rectal cancer underwent resection with curative intent. No patient received neoadjuvant or adjuvant irradiation or chemotherapy. Surgical specimens were assessed for maximum depth of tumor invasion into perirectal fat, lymphatic or venous involvement, and tumor grade. After surgery the clinical course of these patients was assessed for local control, distant metastases, and survival rate. RESULTS: For 25 patients with tumors exhibiting favorable histologic features (well-differentiated or moderately well-differentiated carcinomas invading less than 2 mm into perirectal fat, without lymphatic or venous vessel involvement), the ten-year actuarial rates of local control and recurrence-free survival were 95 and 87 percent, respectively. In contrast, the ten-year actuarial rates of local control and recurrence-free survival were inferior (71 and 55 percent, respectively) for 88 patients with tumors exhibiting moderate to deep perirectal fat invasion, vessel involvement, or poor differentiation. CONCLUSIONS: In the design of future trials of rectal cancer, selection of patients with rectal cancer for postoperative adjuvant therapy should be based not only on stage, but also on depth of invasion into the perirectal fat, vessel involvement, tumor grade, and integrity of the radial resection margin. For subsets of patients with Stage T3N0 rectal cancer, there may be little benefit to adjuvant therapy after surgery.


Subject(s)
Rectal Neoplasms/therapy , Chemotherapy, Adjuvant , Disease-Free Survival , Humans , Neoplasm Staging , Pelvis/radiation effects , Postoperative Care , Prognosis , Radiotherapy, Adjuvant , Rectal Neoplasms/mortality , Rectal Neoplasms/pathology , Retrospective Studies
11.
Med Decis Making ; 18(2 Suppl): S39-56, 1998.
Article in English | MEDLINE | ID: mdl-9566466

ABSTRACT

Predictions of cost over well-defined time horizons are frequently required in the analysis of clinical trials and social experiments, for decision models investigating the cost-effectiveness of interventions, and for macro-level estimates of the resource impact of disease. With rare exceptions, cost predictions used in such applications continue to take the form of deterministic point estimates. However, the growing availability of large administrative and clinical data sets offers new opportunities for a more general approach to disease cost forecasting: the estimation of multivariable cost functions that yield predictions at the individual level, conditional on intervention(s), patient characteristics, and other factors. This raises the fundamental question of how to choose the "best" cost model for a given application. The central purpose of this paper is to demonstrate how to evaluate competing models on the basis of predictive validity. This concept is operationalized according to three alternative criteria: 1) root mean square error (RMSE), for evaluating predicted mean cost; 2) mean absolute error (MAE), for evaluating predicted median cost; and 3) a logarithmic scoring rule (log score), an information-theoretic index for evaluating the entire predictive distribution of cost. To illustrate these concepts, the authors conducted a split-sample analysis of data from a national sample of Medicare-covered patients hospitalized for ischemic stroke in 1991 and followed to the end of 1993. Using test and training samples of about 500,000 observations each, they investigated five models: single-equation linear models, with and without log transform of cost; two-part (mixture) models, with and without log transform, to directly address the problem of zero-cost observations; and a Cox proportional-hazards model stratified by time interval. For deriving the predictive distribution of cost, the log transformed two-part and proportional-hazards models are superior. For deriving the predicted mean or median cost, these two models and the commonly used log-transformed linear model all perform about the same. The untransformed models are dominated in every instance. The approaches to model selection illustrated here can be applied across a wide range of settings.


Subject(s)
Cerebrovascular Disorders/economics , Cost of Illness , Models, Econometric , Costs and Cost Analysis/methods , Hospitalization/economics , Hospitalization/statistics & numerical data , Humans , Models, Statistical , Predictive Value of Tests , Proportional Hazards Models
12.
Med Decis Making ; 17(4): 390-401, 1997.
Article in English | MEDLINE | ID: mdl-9343797

ABSTRACT

A framework for quantifying uncertainty about costs, effectiveness measures, and marginal cost-effectiveness ratios in complex decision models is presented. This type of application requires special techniques because of the multiple sources of information and the model-based combination of data. The authors discuss two alternative approaches, one based on Bayesian inference and the other on resampling. While computationally intensive, these are flexible in handling complex distributional assumptions and a variety of outcome measures of interest. These concepts are illustrated using a simplified model. Then the extension to a complex decision model using the stroke-prevention policy model is described.


Subject(s)
Decision Support Techniques , Health Care Costs/statistics & numerical data , Bayes Theorem , Cerebrovascular Disorders/economics , Cerebrovascular Disorders/prevention & control , Computer Simulation , Cost-Benefit Analysis , Humans , Models, Statistical , Quality-Adjusted Life Years
13.
Ann Intern Med ; 127(8 Pt 2): 704-11, 1997 Oct 15.
Article in English | MEDLINE | ID: mdl-9382384

ABSTRACT

Simulation models that support decision and cost-effectiveness analysis can further the goals of evidence-based medicine by facilitating the synthesis of information from several sources into a single comprehensive structure. The Stroke Prevention Policy Model (SPPM) performs this function for the clinical and policy questions that surround stroke prevention. This paper first describes the basic structure and functions of the SPPM, concentrating on the role of large databases (broadly defined as any database that contains many patients, regardless of study design) in providing the SPPM inputs. Next, recognizing that the use of modeling continues to be a source of some controversy in the medical community, it discusses the philosophical underpinnings of the SPPM. Finally, it discusses conclusions in the context of both stroke prevention and other complex medical decisions. We conclude that despite the difficulties in developing comprehensive models (for example, the length and complexity of model development and validation processes, the proprietary nature of data sources, and the necessity for developing new software), the benefits of such models exceed the costs of continuing to rely on more conventional methods. Although they should not replace the clinician in decision making, comprehensive models based on the best available evidence from large databases can support decision making in medicine.


Subject(s)
Cerebrovascular Disorders/prevention & control , Databases, Factual , Decision Support Systems, Clinical , Evidence-Based Medicine , Practice Guidelines as Topic , Computer Simulation , Humans , United States
14.
Stroke ; 25(6): 1116-21, 1994 Jun.
Article in English | MEDLINE | ID: mdl-8202967

ABSTRACT

BACKGROUND AND PURPOSE: Randomized clinical trials have shown that carotid endarterectomy decreases the risk of subsequent stroke in patients with high-grade carotid stenosis and ipsilateral transient ischemic attack or minor stroke. The benefit of surgery is highly dependent on surgical risk. We previously found that patients with ipsilateral hemispheric symptoms were at greater risk of carotid endarterectomy complications compared with those who were asymptomatic or had nonipsilateral symptoms. The goals of the present study were (1) to identify preoperative clinical factors that may increase the risk of complications after carotid endarterectomy in patients with ipsilateral hemispheric symptoms and (2) to develop a risk index based on this patient-level data. METHODS: Records from 1160 carotid endarterectomies performed at 12 academic medical centers composed the primary data set. Hospital charts for the admission during which carotid endarterectomy was performed were systematically reviewed by abstractors using a defined protocol. The present analysis was carried out on data from the subset of patients who had carotid endarterectomy for ipsilateral hemispheric symptoms. Candidate variables were identified based on univariate Fisher's exact tests or chi 2 tests. A risk index was then developed using those variables with a greater than 90% probability of being associated with adverse outcomes. RESULTS: Of the 697 patients with ipsilateral symptoms, 8.5% had either stroke, myocardial infarction, or died during the postoperative period of hospitalization. Those over the age of 75 had a greater risk of myocardial infarction (6.6% versus 2.3%, P = .024) but not of stroke or death (P > .10). The overall frequencies of adverse outcomes were also higher in the 5 patients with complete ipsilateral carotid occlusions (40% versus 8.2%, P < .01), the 28 patients with ipsilateral intraluminal thrombus (17.9% versus 8.1%, P = .07), and the 65 patients with ipsilateral carotid siphon stenosis (13.9% versus 7.9%, P = .10). There were no differences in adverse outcomes among those with different degrees of ipsilateral stenosis (30% to 49%, 50% to 69%, and 70% to 99%). Adverse outcome rates were similar regardless of the type of symptom (transient ischemic attack, recent ipsilateral minor stroke, remote ipsilateral minor stroke). There were no significant differences in adverse outcome rates based on sex, race, history of angina, recent myocardial infarction, congestive heart failure, chronic obstructive pulmonary disease, hypertension, degree of stenosis of the contralateral carotid artery, or presence of ulceration in the ipsilateral artery (Fisher's exact tests, P > .10). A count of variables with greater than 90% probability of being associated with adverse outcomes (age > or = 75 years or angiographic evidence of ipsilateral carotid occlusion, stenosis in the region of the carotid siphon, or intraluminal thrombus) was used to form a simple risk index. "High-risk" patients (one or more risk factors) had more than two times the risk of complications compared with "low-risk" patients who had no risk factors (odds ratio, 2.18; 95% confidence interval, 1.25 to 3.81). CONCLUSIONS: Certain preoperative clinical variables may place patients with ipsilateral symptoms at greater risk of perioperative complications after carotid endarterectomy. Prospective validation of a simple risk index would provide an additional method for assessing preoperative risk in endarterectomy candidates.


Subject(s)
Carotid Stenosis/physiopathology , Carotid Stenosis/surgery , Cerebrovascular Disorders/physiopathology , Endarterectomy, Carotid/adverse effects , Endarterectomy, Carotid/statistics & numerical data , Ischemic Attack, Transient/physiopathology , Age Factors , Aged , Cause of Death , Cerebrovascular Disorders/etiology , Humans , Ischemic Attack, Transient/etiology , Myocardial Infarction/etiology , North Carolina/epidemiology , Retrospective Studies , Risk Factors , Treatment Outcome
15.
Am J Cardiol ; 72(17): 1220-5, 1993 Dec 01.
Article in English | MEDLINE | ID: mdl-8256695

ABSTRACT

To determine the usefulness of dobutamine stress echocardiography for detecting restenosis after percutaneous transluminal coronary angioplasty, the results of coronary arteriography and dobutamine stress echocardiography were compared in 103 patients 6 months after percutaneous transluminal coronary angiography. The dobutamine stress echocardiograms were obtained on the same day as the coronary arteriograms, which were analyzed by both quantitative and visual estimates of luminal narrowing. The angiographic restenosis rate was 44% by quantitative and 31% by visual estimates of stenosis. Dobutamine stress echocardiography was abnormal in 38% of previously dilated regions with restenosis and normal in 79% of previously dilated regions without restenosis by quantitative coronary angiography. Dobutamine stress echocardiography was concordant in 69% of 16 patients with multivessel disease compared with 40% of 41 patients with 1-vessel disease (p < 0.05). By quantitative coronary angiography, 64% of patients with significant disease in the left anterior descending artery were identified by dobutamine stress echocardiography compared to 12 and 24% of patients with disease in the left circumflex and right coronary arteries, respectively (p < 0.009). Concordance was seen in 79% of patients with baseline wall motion abnormalities compared with 54% of patients without baseline wall motion abnormalities. Dobutamine stress echocardiography has a low sensitivity but high specificity for detecting restenosis after coronary angioplasty, which may be explained in part by the high prevalence of 1-vessel disease in this patient population. The variables associated with significantly higher degrees of concordance were the presence of left anterior descending artery disease, multivessel disease, and baseline wall motion abnormalities.


Subject(s)
Angioplasty, Balloon, Coronary , Coronary Disease/diagnostic imaging , Dobutamine , Echocardiography/methods , Adult , Aged , Chi-Square Distribution , Coronary Disease/therapy , Female , Humans , Male , Middle Aged , Predictive Value of Tests , Radiography , Recurrence , Sensitivity and Specificity
16.
Ann Intern Med ; 119(8): 844-50, 1993 Oct 15.
Article in English | MEDLINE | ID: mdl-8018127

ABSTRACT

OBJECTIVE: To determine the suitability of insurance claims information for use in clinical outcomes research in ischemic heart disease. DESIGN: Concordance study of two databases. SETTING: Tertiary care referral center. PATIENTS: A total of 12,937 consecutive patients hospitalized for cardiac catheterization for suspected ischemic heart disease between July 1985 and May 1990. INTERVENTIONS: Two-by-two tables were used to compute overall and kappa measures of agreement comparing clinical versus claims data for 12 important predictors of prognosis in patients with ischemic heart disease. MEASUREMENTS: Kappa statistics (agreement adjusted for chance agreement) were used to quantify agreement rates. RESULTS: Agreement rates between the clinical and claims databases ranged from 0.83 for the diagnosis of diabetes to 0.09 for the diagnosis of unstable angina (kappa values). Claims data failed to identify more than one half of the patients with prognostically important conditions, including mitral insufficiency, congestive heart failure, peripheral vascular disease, old myocardial infarction, hyperlipidemia, cerebrovascular disease, tobacco use, angina, and unstable angina, when compared with the clinical information system. CONCLUSIONS: Our results suggest that insurance claims data lack important diagnostic and prognostic information when compared with concurrently collected clinical data in the study of ischemic heart disease. Thus, insurance claims data are not as useful as clinical data for identifying clinically relevant patient groups and for adjusting for risk in outcome studies, such as analyses of hospital mortality.


Subject(s)
Coronary Disease/diagnosis , Databases, Factual , Hospital Information Systems , Insurance Claim Reporting , Outcome Assessment, Health Care/standards , Cardiac Catheterization , Comorbidity , Coronary Disease/classification , Coronary Disease/therapy , Hospitalization , Humans , North Carolina , Research Design/standards
17.
Pol Arch Med Wewn ; 84(4): 220-31, 1990 Oct.
Article in Polish | MEDLINE | ID: mdl-2080112

ABSTRACT

The results of a prospective study in 301 patients (pts) with angiographically documented coronary artery disease are presented. The mean follow-up period was 30 +/- 14 months, the mean age of pts was 48 +/- 9 years. A prognostic significance of 37 indicators obtained from clinical, hemodynamical, angiographical and noninvasive studies was investigated. In the group of pts treated medically (n = 202) the natural history of disease was defined by the following indicators: history of myocardial infarction, congestive heart failure, NYHA functional class III and IV, frequent ventricular premature depolarizations (VPD), abnormal ecg at rest, QT greater than QS2 index, left ventricular (LV) ejection fraction less than 50%, elevation of LV end-diastolic pressure and LV end-diastolic volume index LV wall motion abnormalities in particular dyskinesia, left main coronary artery disease and three vessel coronary artery disease. In a multivariate Cox model analysis, the independent correlates of long-term survival were frequency of VPD (p less than 0.001), NYHA functional class III-IV (p less than 0.003), QT greater than QS2 index (p less than 0.01), LV ejection fraction (LVEF) less than 50% (p less than 0.02). The combination of two indicators: LVEF less than 50% and QT greater than QS2 identify pts with high mortality rate (31%) during a two year follow-up period as compared with only 1% in the group with LVEF greater than or equal to 50% and QT less than or equal to QS2. The different clinical and hemodynamical characteristics of both the groups of pts treated medically or surgically made a reliable comparison of those two methods of treatment impossible.


Subject(s)
Coronary Artery Bypass/rehabilitation , Coronary Disease/surgery , Hemodynamics/physiology , Adult , Aged , Cardiac Catheterization , Coronary Angiography , Coronary Artery Bypass/mortality , Coronary Disease/mortality , Coronary Disease/physiopathology , Coronary Vessels/physiopathology , Humans , Middle Aged , Postoperative Period , Prognosis , Time Factors
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