Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
AIDS Patient Care STDS ; 20(8): 565-75, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16893326

RESUMEN

The aim of the study was a prospective assessment of the possible consequences of a diagnosis of lipodystrophy on health-related quality of life (HRQL) and depressive symptomatology in HIV-seropositive men who have sex with men. A standardized physical assessment for lipodystrophy was introduced within a prospective study in April 1999. Over a 2-year follow- up, 37 HIV-seropositive men who met the criteria for lipodystrophy were longitudinally compared to 92 HIV-seropositive men without lipodystrophy and 88 HIV-seronegative men on measures of HRQL and depression. A series of questionnaires, which included the Medical Outcomes Study Short-Form 36 (SF-36) and the Center for Epidemiological Studies-Depression (CES-D), were administered to assess HRQL and depression, respectively. SF-36 scores were summarized using the mental and physical components; CES-D results were reported as both dichotomous (with or with clinical depression) and continuous scores. Neither the mental nor physical components of the SF-36 showed any significant differences between patients with lipodystrophy versus HIV-seropositive patients without lipodystrophy. Similarly, lipodystrophy status was not significantly associated with either continuous depression scores or presence of clinical depression. However, consistent with previous results, HIV-seropositive men without lipodystrophy (compared to HIV-seronegative men) reported higher scores on both components of the SF-36 scales and both categorizations of the CES-D. The results of this study suggest that lipodystrophy does not negatively affect HRQL or depression, above and beyond, the diagnosis of HIV infection, although the impact of the severity of lipodystrophy on these conditions will require further study.


Asunto(s)
Terapia Antirretroviral Altamente Activa/efectos adversos , Depresión/epidemiología , Síndrome de Lipodistrofia Asociada a VIH/epidemiología , Homosexualidad Masculina , Calidad de Vida , Adulto , Anciano , Estudios de Casos y Controles , Depresión/etiología , Síndrome de Lipodistrofia Asociada a VIH/inducido químicamente , Síndrome de Lipodistrofia Asociada a VIH/psicología , Homosexualidad Masculina/psicología , Homosexualidad Masculina/estadística & datos numéricos , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Pennsylvania/epidemiología , Prevalencia , Estudios Prospectivos
2.
JAMA ; 286(18): 2251-6, 2001 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-11710890

RESUMEN

CONTEXT: Among cancer-free women aged 35 years or older, tamoxifen reduced the incidence of estrogen receptor (ER)-positive but not ER-negative breast cancer. The effect of tamoxifen on breast cancer incidence among women at extremely high risk due to inherited BRCA1 or BRCA2 mutations is unknown. OBJECTIVE: To evaluate the effect of tamoxifen on incidence of breast cancer among cancer-free women with inherited BRCA1 or BRCA2 mutations. DESIGN, SETTING, AND PARTICIPANTS: Genomic analysis of BRCA1 and BRCA2 for 288 women who developed breast cancer after entry into the randomized, double-blind Breast Cancer Prevention Trial of the National Surgical Adjuvant Breast and Bowel Project (between April 1, 1992, and September 30, 1999). MAIN OUTCOME MEASURE: Among women with BRCA1 or BRCA2 mutations, incidence of breast cancer among those who were receiving tamoxifen vs incidence of breast cancer among those receiving placebo. RESULTS: Of the 288 breast cancer cases, 19 (6.6%) inherited disease-predisposing BRCA1 or BRCA2 mutations. Of 8 patients with BRCA1 mutations, 5 received tamoxifen and 3 received placebo (risk ratio, 1.67; 95% confidence interval, 0.32-10.70). Of 11 patients with BRCA2 mutations, 3 received tamoxifen and 8 received placebo (risk ratio, 0.38; 95% confidence interval, 0.06-1.56). From 10 studies, including this one, 83% of BRCA1 breast tumors were ER-negative, whereas 76% of BRCA2 breast tumors were ER-positive. CONCLUSION: Tamoxifen reduced breast cancer incidence among healthy BRCA2 carriers by 62%, similar to the reduction in incidence of ER-positive breast cancer among all women in the Breast Cancer Prevention Trial. In contrast, tamoxifen use beginning at age 35 years or older did not reduce breast cancer incidence among healthy women with inherited BRCA1 mutations. Whether tamoxifen use at a younger age would reduce breast cancer incidence among healthy women with BRCA1 mutations remains unknown.


Asunto(s)
Antineoplásicos Hormonales/uso terapéutico , Neoplasias de la Mama/genética , Neoplasias de la Mama/prevención & control , Genes BRCA1 , Genes BRCA2 , Tamoxifeno/uso terapéutico , Adulto , Anciano , Neoplasias de la Mama/epidemiología , Neoplasias de la Mama/metabolismo , Análisis Mutacional de ADN , Método Doble Ciego , Femenino , Predisposición Genética a la Enfermedad , Humanos , Incidencia , Persona de Mediana Edad , Mutación , Receptores de Estrógenos , Factores de Riesgo
3.
Semin Oncol ; 28(1 Suppl 1): 9-13, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11273592

RESUMEN

During the last decade, the National Surgical Adjuvant Breast and Bowel Project (NSABP) has completed six adjuvant chemotherapy trials comparing different adjuvant therapy regimens or adjuvant therapy versus surgery alone. A seventh trial is ongoing. These trials have contributed to defining the role of adjuvant therapy in colon cancer. Patients eligible for inclusion in NSABP trials had been diagnosed as having stage II or III colon cancer with no evidence of gross residual or metastatic disease. The follow-up strategies were similar in the reported trials with follow-up every 3 months for the first 2 years, then every 6 months for the next 3 to 5 years, and annually thereafter. The NSABP C-01 protocol was a three-arm trial comparing an adjuvant semustine/vincristine/5-fluorouracil (5-FU) regimen (MOF) to a Bacille Calmette-Guerin treatment, and to surgery alone. The C-02 protocol investigated whether portal vein infusion of 5-FU improved survival outcome compared with surgery alone. Protocol C-03 compared a semustine/vincristine/5-FU regimen to a 5-FU plus leucovorin (LV) (5-FU/LV) regimen. The NSABP C-04 protocol was a three-arm trial comparing 5-FU/LV, 5-FU plus levamisole, and 5-FU/LV plus levamisole. The NSABP C-05 trial compared 5-FU/LV to 5-FU/LV plus alpha-interferon. Results of NSABP C-01, C-02, C-03, C-04, and C-05 trials are summarized in this report. Patient accrual has completed in the NSABP C-06 trial comparing 5-FU/LV with oral tegafur and plus uracil leucovorin. The NSABP is currently conducting another trial (C-07) comparing 5-FU/LV with 5-FU/LV plus oxaliplatin. The role of adjuvant chemotherapy in stage II colon cancer is also discussed in this report. A recent pooled analysis of studies C-01, C-02, C-03, and C-04 has indicated that the relative treatment benefit in stage II disease is at least equal to the benefit in stage III colon cancers, and concluded that adjuvant chemotherapy also should be considered as the standard of care for stage II colon cancer patients.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Ensayos Clínicos como Asunto , Neoplasias del Colon/tratamiento farmacológico , Adyuvantes Inmunológicos/administración & dosificación , Vacuna BCG/uso terapéutico , Quimioterapia Adyuvante , Neoplasias del Colon/patología , Neoplasias del Colon/cirugía , Fluorouracilo/administración & dosificación , Humanos , Infusiones Intravenosas , Leucovorina/administración & dosificación , Levamisol/administración & dosificación , Estadificación de Neoplasias , Semustina/administración & dosificación , Tegafur/administración & dosificación , Vincristina/administración & dosificación
4.
Stat Med ; 19(4): 511-23, 2000 Feb 29.
Artículo en Inglés | MEDLINE | ID: mdl-10694733

RESUMEN

In this paper we study a class of non-parametric statistics for comparing diagnostic markers with repeated measurements. Using adapted definitions of specificity and sensitivity, we suggest methods to compare the average of sensitivities across all specificities or a range of specificities. The theory allows for correlations introduced by the fact that markers may be obtained from the same patient at multiple visits and that both markers being compared may be obtained from the same patient. Results of the Monte Carlo simulations and an example from a breast cancer setting are provided.


Asunto(s)
Técnicas y Procedimientos Diagnósticos/estadística & datos numéricos , Curva ROC , Estadísticas no Paramétricas , Biomarcadores de Tumor/sangre , Neoplasias de la Mama/sangre , Neoplasias de la Mama/patología , Antígeno Carcinoembrionario/sangre , Simulación por Computador , Supervivencia sin Enfermedad , Femenino , Humanos , Método de Montecarlo , Mucina-1/sangre , Ensayos Clínicos Controlados Aleatorios como Asunto , Sensibilidad y Especificidad
5.
J Clin Oncol ; 17(11): 3553-9, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-10550154

RESUMEN

PURPOSE: To compare the efficacy of leucovorin-modulated fluorouracil (FU+LV) with that of fluorouracil and levamisole (FU+LEV) or with the combination of FU+LV and levamisole (FU+LV+LEV). PATIENTS AND METHODS: Between July 1989 and December 1990, 2,151 patients with Dukes' B (stage II) and Dukes' C (stage III) carcinoma of the colon were entered onto National Surgical Adjuvant Breast and Bowl Project protocol C-04. Patients were randomly assigned to receive FU+LV (weekly regimen), FU + LEV, or the combination of FU+LV+LEV. The average time on study was 86 months. RESULTS: A pairwise comparison between patients treated with FU+LV or FU+LEV disclosed a prolongation in disease-free survival (DFS) in favor of the FU+LV group (65% v 60%; P =.04); there was a small prolongation in overall survival that was of borderline significance (74% v 70%; P =.07). There was no difference in the pairwise comparison between patients who received FU+LV or FU+LV+LEV for either DFS (65% v 64%; P =.67) or overall survival (74% v 73%; P =.99). There was no interaction between Dukes' stage and the effect of treatment. CONCLUSION: In patients with Dukes' B and C carcinoma of the colon, treatment with FU+LV seems to confer a small DFS advantage and a borderline prolongation in overall survival when compared with treatment with FU+LEV. The addition of LEV to FU+LV does not provide any additional benefit over and above that achieved with FU+LV. These findings support the use of adjuvant FU+LV as an acceptable therapeutic standard in patients with Dukes' B and C carcinoma of the colon.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma/tratamiento farmacológico , Neoplasias del Colon/tratamiento farmacológico , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Carcinoma/mortalidad , Carcinoma/patología , Quimioterapia Adyuvante , Neoplasias del Colon/mortalidad , Neoplasias del Colon/patología , Supervivencia sin Enfermedad , Femenino , Fluorouracilo/administración & dosificación , Humanos , Leucovorina/administración & dosificación , Levamisol/administración & dosificación , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia
6.
J Clin Oncol ; 17(5): 1349-55, 1999 May.
Artículo en Inglés | MEDLINE | ID: mdl-10334518

RESUMEN

PURPOSE: Although the benefit from adjuvant chemotherapy has been clearly established in patients with Dukes' C colon cancer, such benefit has been questioned in patients with Dukes' B disease. To determine whether patients with Dukes' B disease benefit from adjuvant chemotherapy and to evaluate the magnitude of the benefit, compared with that observed in Dukes' C patients, we examined the relative efficacy of adjuvant chemotherapy according to Dukes' stage in four sequential National Surgical Adjuvant Breast and Bowel Project trials (C-01, C-02, C-03, and C-04) that compared different adjuvant chemotherapy regimens with each other or with no adjuvant treatment. PATIENTS AND METHODS: The four trials included Dukes' B and C patients and were conducted between 1977 and 1990. The eligibility criteria and follow-up requirements were similar for all four trials. Protocol C-01 compared adjuvant semustine, vincristine, and fluorouracil (5-FU) (MOF regimen) with operation alone. Protocol C-02 compared the perioperative administration of a portal venous infusion of 5-FU with operation alone. Protocol C-03 compared adjuvant 5-FU and leucovorin (LV) with adjuvant MOF. Protocol C-04 compared adjuvant 5-FU and LV with 5-FU and levamisole (LEV) and with the combination of 5-FU, LV, and LEV. RESULTS: Forty-one percent of the patients included in these four trials had resected Dukes' B tumors. In all four studies, the overall, disease-free, and recurrence-free survival improvement noted for all patients was evident in both Dukes' B and Dukes' C patients. When the relative efficacy of chemotherapy was examined, there was always an observed reduction in mortality, recurrence, or disease-free survival event, irrespective of Dukes' stage, and in most instances, the reduction was as great or greater for Dukes' B patients as for Dukes' C patients. When data from all four trials were examined in a combined analysis, the mortality reduction was 30% for Dukes' B patients versus 18% for Dukes' C patients. The mortality reduction in Dukes' B patients occurred irrespective of the presence or absence of adverse prognostic factors. CONCLUSION: Patients with Dukes' B colon cancer benefit from adjuvant chemotherapy and should be presented with this treatment option. Regardless of the presence or absence of other clinical prognostic factors, Dukes' B patients seem to benefit from chemotherapy administration.


Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/cirugía , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/cirugía , Adenocarcinoma/patología , Antídotos/administración & dosificación , Quimioterapia Adyuvante , Neoplasias del Colon/patología , Fluorouracilo/administración & dosificación , Humanos , Leucovorina/administración & dosificación , Estadificación de Neoplasias , Ensayos Clínicos Controlados Aleatorios como Asunto , Semustina/administración & dosificación , Análisis de Supervivencia , Vincristina/administración & dosificación
7.
Stat Med ; 17(22): 2563-78, 1998 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-9839348

RESUMEN

We consider methods for evaluating repeated markers to be used as a substitute for a clinical examination or to predict an outcome, in our case progression of breast cancer. We propose a definition of specificity and sensitivity for this setting and describe non-parametric estimators for these parameters. We then derive the theory required to obtain confidence intervals for the specificity and sensitivity of a marker and to define an asymptotically normal statistic for comparing the sensitivities of two markers at a fixed specificity. The theory allows for correlations introduced by the fact that markers may be obtained from the same patient at multiple visits and that both markers being compared may be obtained from the same patient. The work allows for an approach that complements the frequently used time dependent Cox model, which we believe, will facilitate clinical interpretation of marker data.


Asunto(s)
Biomarcadores de Tumor/análisis , Neoplasias de la Mama/diagnóstico , Modelos Estadísticos , Antígeno Carcinoembrionario/análisis , Intervalos de Confianza , Progresión de la Enfermedad , Humanos , Mucina-1/análisis , Péptidos/análisis , Sensibilidad y Especificidad , Estadísticas no Paramétricas , Resultado del Tratamiento
8.
J Natl Cancer Inst ; 90(18): 1371-88, 1998 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-9747868

RESUMEN

BACKGROUND: The finding of a decrease in contralateral breast cancer incidence following tamoxifen administration for adjuvant therapy led to the concept that the drug might play a role in breast cancer prevention. To test this hypothesis, the National Surgical Adjuvant Breast and Bowel Project initiated the Breast Cancer Prevention Trial (P-1) in 1992. METHODS: Women (N=13388) at increased risk for breast cancer because they 1) were 60 years of age or older, 2) were 35-59 years of age with a 5-year predicted risk for breast cancer of at least 1.66%, or 3) had a history of lobular carcinoma in situ were randomly assigned to receive placebo (n=6707) or 20 mg/day tamoxifen (n=6681) for 5 years. Gail's algorithm, based on a multivariate logistic regression model using combinations of risk factors, was used to estimate the probability (risk) of occurrence of breast cancer over time. RESULTS: Tamoxifen reduced the risk of invasive breast cancer by 49% (two-sided P<.00001), with cumulative incidence through 69 months of follow-up of 43.4 versus 22.0 per 1000 women in the placebo and tamoxifen groups, respectively. The decreased risk occurred in women aged 49 years or younger (44%), 50-59 years (51%), and 60 years or older (55%); risk was also reduced in women with a history of lobular carcinoma in situ (56%) or atypical hyperplasia (86%) and in those with any category of predicted 5-year risk. Tamoxifen reduced the risk of noninvasive breast cancer by 50% (two-sided P<.002). Tamoxifen reduced the occurrence of estrogen receptor-positive tumors by 69%, but no difference in the occurrence of estrogen receptor-negative tumors was seen. Tamoxifen administration did not alter the average annual rate of ischemic heart disease; however, a reduction in hip, radius (Colles'), and spine fractures was observed. The rate of endometrial cancer was increased in the tamoxifen group (risk ratio = 2.53; 95% confidence interval = 1.35-4.97); this increased risk occurred predominantly in women aged 50 years or older. All endometrial cancers in the tamoxifen group were stage I (localized disease); no endometrial cancer deaths have occurred in this group. No liver cancers or increase in colon, rectal, ovarian, or other tumors was observed in the tamoxifen group. The rates of stroke, pulmonary embolism, and deep-vein thrombosis were elevated in the tamoxifen group; these events occurred more frequently in women aged 50 years or older. CONCLUSIONS: Tamoxifen decreases the incidence of invasive and noninvasive breast cancer. Despite side effects resulting from administration of tamoxifen, its use as a breast cancer preventive agent is appropriate in many women at increased risk for the disease.


Asunto(s)
Antineoplásicos Hormonales/uso terapéutico , Neoplasias de la Mama/etiología , Neoplasias de la Mama/prevención & control , Antagonistas de Estrógenos/uso terapéutico , Tamoxifeno/uso terapéutico , Adulto , Neoplasias de la Mama/complicaciones , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Causas de Muerte , Femenino , Humanos , Persona de Mediana Edad , Invasividad Neoplásica , Oportunidad Relativa , Calidad de Vida , Riesgo , Factores de Riesgo , Resultado del Tratamiento
9.
J Clin Oncol ; 15(7): 2483-93, 1997 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9215816

RESUMEN

PURPOSE: To determine whether preoperative doxorubicin and cyclophosphamide (AC) permits more lumpectomies to be performed and decreases the incidence of positive nodes in women with primary breast cancer. PATIENTS AND METHODS: Women (n = 1,523) were randomized to National Surgical Adjuvant Breast and Bowel Project (NSABP) B-18; 759 eligible patients received postoperative AC and 747, preoperative AC. The clinical size of breast and axillary tumors was determined before each of four cycles of AC and before surgery. Tumor response to preoperative therapy was clinically complete (cCR), partial (cPR), stable (cSD), or progressive disease (cPD). Tissue from patients with a cCR was evaluated for a pathologic complete response (pCR). RESULTS: Breast tumor size was reduced in 80% of patients after preoperative therapy; 36% had a cCR. Tumor size and clinical nodal status were independent predictors of cCR. Twenty-six percent of women with a cCR had a pCR. Clinical nodal response occurred in 89% of node-positive patients: 73% had a cCR and 44% of those had a pCR. There was a 37% increase in the incidence of pathologically negative nodes. Before randomization, lumpectomy was proposed for 86% of women with tumors < or = 2 cm, 70% with tumors 2.1 to 5.0 cm, and 3% with tumors > or = 5.1 cm. Clinical tumor size and nodal status influenced the physician's decision. Overall, 12% more lumpectomies were performed in the preoperative group; in women with tumors > or = 5.1 cm, there was a 175% increase. CONCLUSION: Preoperative therapy reduced the size of most breast tumors and decreased the incidence of positive nodes. The greatest increase in lumpectomy after preoperative therapy occurred in women with tumors > or = 5 cm, since women with tumors less than 5 cm were already lumpectomy candidates. Preoperative therapy should be considered for the initial management of breast tumors judged too large for lumpectomy.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/patología , Mastectomía Segmentaria , Recurrencia Local de Neoplasia/prevención & control , Antibióticos Antineoplásicos/administración & dosificación , Antineoplásicos Alquilantes/administración & dosificación , Neoplasias de la Mama/cirugía , Quimioterapia Adyuvante , Ciclofosfamida/administración & dosificación , Doxorrubicina/administración & dosificación , Femenino , Humanos , Metástasis Linfática , Persona de Mediana Edad , Cuidados Preoperatorios , Resultado del Tratamiento
11.
Stat Med ; 14(20): 2217-25, 1995 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-8552898

RESUMEN

A proliferation of biologic markers has led to increased interest in methods for comparing the prognostic value of markers in predicting time to recurrence of or death from disease. This paper proposes a nonparametric test statistic for comparing two continuous markers when the outcome of interest is time to an event and the outcome is subject to right censoring. Results from Monte Carlo studies show that the new testing procedure is reliable for practical use. We present an example in which we use the statistic successfully in a colon cancer study to select between two potentially useful markers.


Asunto(s)
Biomarcadores , Supervivencia sin Enfermedad , Estadísticas no Paramétricas , Adenocarcinoma/patología , Biomarcadores de Tumor , Neoplasias Colorrectales/patología , Simulación por Computador , ADN de Neoplasias , Interpretación Estadística de Datos , Fase G2 , Humanos , Modelos Logísticos , Pronóstico , Recurrencia , Reproducibilidad de los Resultados , Fase S , Factores de Tiempo
14.
Stat Med ; 13(13-14): 1453-8, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-7973224

RESUMEN

We discuss a procedure that offers the possibility of reducing the number of patients assigned to experimental regimens which are no more effective than a standard regimen. The procedure is useful in advanced cancer trials in which the length of the accrual period might be more than twice the median survival time for the standard regimen. The procedure is intuitively appealing and offers a 50 per cent chance of stopping accrual to ineffective therapies, yet is associated with a loss of power of less than 0.02.


Asunto(s)
Interpretación Estadística de Datos , Ensayos Clínicos Controlados Aleatorios como Asunto/estadística & datos numéricos , Análisis de Supervivencia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Estudios de Seguimiento , Humanos , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/mortalidad , Tasa de Supervivencia
15.
Stat Med ; 11(1): 5-11, 1992 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-1557575

RESUMEN

A screening design was used in a trial that compared a standard regimen to five experimental regimens for the treatment of advanced colorectal cancer where the endpoint was survival. The two-stage design permitted the termination of accrual to experimental regimens that failed to show promise at the first stage. It also allowed for termination of accrual to the standard regimen if an experimental regimen appeared to offer a highly significant improvement over the standard regimen. This paper presents a description of the design and the results of the trial.


Asunto(s)
Teorema de Bayes , Neoplasias Colorrectales/mortalidad , Cisplatino/administración & dosificación , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/cirugía , Terapia Combinada , Relación Dosis-Respuesta a Droga , Fluorouracilo/administración & dosificación , Estudios de Seguimiento , Humanos , Leucovorina/administración & dosificación , Metotrexato/administración & dosificación , Tasa de Supervivencia
16.
Control Clin Trials ; 9(2): 107-18, 1988 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-3396362

RESUMEN

A design for testing new anticancer agents is proposed such that the initial testing of new agents (phase II trials) is included within the framework of a comparative clinical trial (phase III). Randomization between phase II trials and the treatment groups of the phase III trial enforces consistency of patient selection and evaluation of response criteria. Patients who progress on the phase II trials of the new agents are randomized to one of the treatments of the phase III trial. Design issues, such as sample size and power, and analysis of the proposed design, are discussed. Advantages and disadvantages of the design are illustrated by sample size calculations for a current clinical trial in advanced breast cancer.


Asunto(s)
Antineoplásicos/uso terapéutico , Ensayos Clínicos como Asunto/métodos , Evaluación de Medicamentos/métodos , Proyectos de Investigación , Antineoplásicos/efectos adversos , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/mortalidad , Humanos , Probabilidad , Distribución Aleatoria , Estadística como Asunto
17.
Control Clin Trials ; 8(1): 20-8, 1987 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-3568693

RESUMEN

A two-stage rule for a randomized clinical trial with a dichotomous outcome is presented. It is based on a rule discussed by Ellenberg and Eisenberger (Cancer Treat Rep 69:1147-1154, 1985). The rule is shown to lead to a reduction in expected sample size if the test treatment is ineffective, with almost no loss in power. All the mathematical formulas required to design such a rule are given, as well as some time-saving approximations. The accuracy of the approximations is shown.


Asunto(s)
Ensayos Clínicos como Asunto/métodos , Humanos , Distribución Aleatoria , Estadística como Asunto
18.
N Engl J Med ; 309(4): 197-204, 1983 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-6866032

RESUMEN

We prospectively evaluated and followed 204 patients with syncope to determine how often a cause of syncope could be established and to define the prognosis of such patients. A cardiovascular cause was established in 53 patients and a noncardiovascular cause in 54. The cause remained unknown in 97 patients. At 12 months, the overall mortality was 14 +/- 2.5 per cent. The mortality rate (30 +/- 6.7 per cent) in patients with a cardiovascular cause of syncope was significantly higher than the rate (12 +/- 4.4 per cent) in patients with a noncardiovascular cause (P = 0.02) and the rate (6.4 +/- 2.8 per cent) in patients with syncope of unknown origin (P less than 0.0001). The incidence of sudden death was 24 +/- 6.6 per cent in patients with a cardiovascular cause, as compared with 4 +/- 2.7 per cent in patients with a noncardiovascular cause (P = 0.005) and 3 +/- 1.8 per cent in patients with syncope of unknown origin (P = 0.0002). Patients with syncope can be separated into diagnostic categories that have prognostic importance. Patients with a cardiovascular cause have a strikingly higher incidence of sudden death than patients with a noncardiovascular or unknown cause.


Asunto(s)
Enfermedades Cardiovasculares/complicaciones , Síncope/etiología , Adolescente , Adulto , Anciano , Muerte Súbita , Electrocardiografía , Electroencefalografía , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Prospectivos , Síncope/diagnóstico , Síncope/mortalidad
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA