Risk of cardiovascular adverse events from trastuzumab (Herceptin(®)) in elderly persons with breast cancer: a population-based study.

Randomized controlled trials have reported a 4-5 times increased risk of heart failure (HF) in breast cancer patients receiving trastuzumab (Herceptin (®) ) compared to patients who do not receive trastuzumab. However, data regarding the cardiac effects of trastuzumab on elderly patients treated in general practice remain very limited. Using the US surveillance, epidemiology, and end results (SEER)-Medicare database, we conducted a retrospective cohort study on the cardiac effects of trastuzumab use in all incident breast cancer patients diagnosed from 1998 to 2007 who were 66 years and older, had no prior recent claims for cardiomyopathy (CM) or HF, and were followed through 2009. We defined our outcome as the first CM/HF event after diagnosis. We performed Cox-proportional hazard models with propensity score adjustment to estimate CM/HF risk associated with trastuzumab use. A total of 6,829 out of 68,536 breast cancer patients (median age: 75) had an incident CM/HF event. Patients who received trastuzumab tended to be younger, non-white, diagnosed more recently, and had a stage IV diagnosis. Trastuzumab use was associated with an increased risk of CM/HF (HR = 2.08, 95 % CI 1.77-2.44, p < 0.001). The trastuzumab-associated CM/HF risk was stronger in patients who were younger (HR = 2.52 for 66-75 years and HR = 1.44 for 76 years and older, p < 0.001) and diagnosed in recent years (HR = 2.58 for 2006-2007 vs. 1.86 for 1998-2005, p = 0.01). The twofold risk of CM/HF associated with trastuzumab remained regardless of patients' diagnosis stage, presence of hypertension, cardiovascular comorbidities, or receipt of anthracyclines, taxanes, or radiation. Trastuzumab may double CM/HF risk among elderly breast cancer patients. Our findings reinforce the need to prevent and manage cardiac risk among elderly breast cancer patients receiving trastuzumab.

Bevacizumab use and risk of cardiovascular adverse events among elderly patients with colorectal cancer receiving chemotherapy: a population-based study.

BACKGROUND: Cardiovascular risk attributable to bevacizumab (Avastin(®), BEV) for treatment of metastatic colorectal cancer (CRC) remains unclear. We conducted a population-based cohort study to assess the safety of BEV use among patients aged ≥ 65. PATIENTS AND METHODS: We identified CRC patients diagnosed from 2005 to 2007 who received chemotherapy and were followed until 31 December 2009. Outcomes were 3-year risk of arterial thromboembolic events (ATEs), cardiomyopathy or congestive heart failure (CM/CHF), and cardiac death (CD) after chemotherapy initiation. We fitted Cox-proportional hazards (PHs) models with inverse-probability-of-treatment-weights and calculated hazard ratios (HRs) for the risk of adverse events. RESULTS: We identified 6803 CRC patients (median age: 73 years). Those with cardiac comorbidity were less likely to receive BEV (P < 0.0001). BEV is associated with an elevated risk of ATEs (HR = 1.82, 95% CI = 1.20-2.76, P < 0.001; rate difference: 3.5 additional cases/1000 person-years). We observed no association between BEV and CD or CM/CHF. CONCLUSIONS: In general practice, the cardiovascular risk of BEV in elderly CRC is modest. The observed ATEs risk is lower than reported in clinical trials, which may be due to careful patient selection. Our findings may facilitate clinical decision-making of BEV use in elderly patients.

Impact of screening on incidence and mortality of prostate cancer in the United States.

The potential confounding influence of changing treatment patterns and misattribution bias make a definitive conclusion about the link between PSA screening and mortality rates tentative at best. At least some of the mortality decline since 1991 appears likely to be due to screening, but the precise magnitude of the screening effect is difficult to estimate. The possible reduction in mortality due to screening, while uncertain, must be weighed against the substantial decrements in treatment-specific health outcomes (32-34) among men treated for clinically localized tumors typically detected by screening. Population data and ongoing screening trials in the United States and Europe (24, 35) will be complementary in the final determination of the relative contribution of the impact of screening versus other causes on recent mortality trends.

Comparison of self-reported initial treatment with medical records: results from the prostate cancer outcomes study.

Medical records are generally accepted as the most accurate source of information documenting cancer treatments. However, as the health care system becomes more decentralized and more cancer care is delivered in outpatient settings, it is increasingly difficult and expensive to review records from the many surgeons and medical/radiation oncologists who administer cancer therapies in the community setting. Using 1994-1995 data, the authors compared initial treatment for prostate cancer self-reported (from a mailed questionnaire or telephone/in-person interview) by 3,196 US men in the population-based Prostate Cancer Outcomes Study with information obtained from medical records. Agreement between self-reports and medical records varied by type of treatment. Generally, agreement was excellent for more invasive procedures such as prostatectomy or radiation (kappa values > 0.8), with decreasing agreement for hormone shots and pills (kappa values < 0.7). If the medical record abstract is assumed to be the "gold standard," the estimated sensitivity was generally high (>80%) for prostatectomy and radiation but low (68%) for hormone pills, although the estimated specificity was 90% or greater for all treatments. These results can serve as a useful guide to researchers contemplating the use of surveys as an alternative to medical record abstraction to ascertain treatment in studies of patient outcomes.

Quality-of-life outcomes after primary androgen deprivation therapy: results from the Prostate Cancer Outcomes Study.

PURPOSE: To compare health-related quality-of-life outcomes after primary androgen deprivation (AD) therapy with orchiectomy versus luteinizing hormone-releasing hormone (LHRH) agonists for patients with prostate cancer. PATIENTS AND METHODS: Men (n = 431) newly diagnosed with all stages of prostate cancer from six geographic regions who participated in the Prostate Cancer Outcomes Study and who received primary AD therapy but no other treatments within 12 months of initial diagnosis were included in a study of health outcomes. Comparisons were statistically adjusted for patient sociodemographic and clinical characteristics, timing of therapy, and use of combined androgen blockade. RESULTS: More than half of the patients receiving primary AD therapy had been initially diagnosed with clinically localized prostate cancer. Among these patients, almost two thirds were at high risk of progression on the basis of prognostic factors. Sexual function outcomes were similar by treatment group both before and after implementation of AD therapy. LHRH patients reported more breast swelling than did orchiectomy patients (24.9% v 9.7%, P <.01). LHRH patients reported more physical discomfort and worry because of cancer or its treatment than did orchiectomy patients. LHRH patients assessed their overall health as fair or poor more frequently than did orchiectomy patients (35.4% v 28.1%, P =.01) and also were less likely to consider themselves free of prostate cancer after treatment. CONCLUSION: Most endocrine-related health outcomes are similar after surgical versus medical primary hormonal therapy. Stage at diagnosis had little effect on outcomes. These results provide representative information comparing surgical and medical AD therapy that may be used by physicians and patients to inform treatment decisions.

Health outcomes after external-beam radiation therapy for clinically localized prostate cancer: results from the Prostate Cancer Outcomes Study.

PURPOSE: Studies reporting effects of radiotherapy for prostate cancer on sexual, bowel, and urinary function have been conducted primarily in referral centers or academic institutions. Effects of external-beam radiotherapy for prostate cancer among a population-based cohort were assessed. PATIENTS AND METHODS: The study population included 497 white, Hispanic, and African-American men with localized prostate cancer from six US cancer registries who were diagnosed between October 1, 1994, and October 31, 1995, and treated initially with external-beam radiotherapy. They were interviewed at regular intervals, and medical records were reviewed. Distributions of responses for bowel-, urinary-, and sexual-related functions at 6, 12, and 24 months after diagnosis and adjusted mean composite change scores for each domain were analyzed. RESULTS: Declines of 28.9% in the sexual function score and 5.4% in the bowel function score occurred by 24 months, whereas at this time, the urinary function score was relatively unchanged. A total of 43% of those who were potent before diagnosis became impotent after 24 months. More than two thirds of the men were satisfied with their treatment and would make the same decision again. CONCLUSION: Sexual function was the most adversely affected quality-of-life domain, with problems continuing to increase between 12 and 24 months. Bowel function problems increased at 6 months, with partial resolution observed by 24 months. Despite the side effects, satisfaction with therapy was high. These results are representative of men in community practice settings and may be of assistance to men and to clinicians when making treatment decisions.

Racial and ethnic differences in advanced-stage prostate cancer: the Prostate Cancer Outcomes Study.

BACKGROUND: African-Americans have twice the risk of non-Hispanic whites for presenting with advanced-stage prostate cancer. To investigate the reasons for this difference, we evaluated the association between race/ethnicity and advanced-stage prostate cancer, adjusting for demographic, socioeconomic, clinical, and pathologic factors. METHODS: A population-based cohort of 3173 men diagnosed with prostate cancer between October 1, 1994, and October 31, 1995, was analyzed. Medical record abstracts and self-administered survey questionnaires were used to obtain information regarding race/ethnicity, age, marital status, insurance status, educational level, household income, employment status, comorbidity, urinary function, prostate-specific antigen level, tumor grade, and clinical stage. The odds ratio (OR) for advanced-stage prostate cancer was estimated with weighted logistic regression analysis. All P: values were two-sided. RESULTS: Clinically advanced-stage prostate cancers were detected more frequently in African-Americans (12.3%) and Hispanics (10.5%) than in non-Hispanic whites (6.3%). Socioeconomic, clinical, and pathologic factors each accounted for about 15% of the increased relative risk. After adjusting for all covariates, the risk remained statistically significantly increased for African-Americans (OR = 2.26; 95% confidence interval [CI] = 1.43 to 3.58) but not for Hispanics (OR = 1.23; 95% CI = 0.73 to 2.08). CONCLUSION: Traditional socioeconomic, clinical, and pathologic factors accounted for the increased relative risk for presenting with advanced-stage prostate cancer in Hispanic but not in African-American men.

Measuring the incremental cost of clinical cancer research.

PURPOSE: To summarize evidence on the costs of treating patients in clinical trials and to describe the Cost of Cancer Treatment Study, an ongoing effort to produce generalizable estimates of the incremental costs of government-sponsored cancer trials. METHODS: A retrospective study of costs will be conducted with 1,500 cancer patients recruited from a randomly selected sample of institutions in the United States. Patients accrued to either phase II or phase III National Cancer Institute-sponsored clinical trials during a 15-month period will be asked to participate in a study of their health care utilization (n = 750). Costs will be measured approximately 1 year after their trial enrollment from a combination of billing records, medical records, and an in-person survey questionnaire. Similar data will be collected for a comparable group of cancer patients not in trials (n = 750) to provide an estimate of the incremental cost. RESULTS: Evidence suggests insurers limit access to trials because of cost concerns. Public and private efforts are underway to change these policies, but their permanent status is unclear. Previous studies found that treatment costs in clinical trials are similar to costs of standard therapy. However, it is difficult to generalize from these studies because of the unique practice settings, insufficient sample sizes, and the exclusion of potentially important costs. CONCLUSION: Denials of coverage for treatment in a clinical trial limit patient access to trials and could impede clinical research. Preliminary estimates suggest changes to these policies would not be expensive, but these results are not generalizable. The Cost of Cancer Treatment Study is an ongoing effort to provide generalizable estimates of the incremental treatment cost of phase II and phase III cancer trials. The results should be of great interest to insurers and the research community as they consider permanent ways to finance cancer trials.

Health outcomes after prostatectomy or radiotherapy for prostate cancer: results from the Prostate Cancer Outcomes Study.

BACKGROUND: Radical prostatectomy and external beam radiotherapy are the two major therapeutic options for treating clinically localized prostate cancer. Because survival is often favorable regardless of therapy, treatment decisions may depend on other therapy-specific health outcomes. In this study, we compared the effects of two treatments on urinary, bowel, and sexual functions and on general health-related quality-of-life outcomes over a 2-year period following initial treatment. METHODS: A diverse cohort of patients aged 55-74 years who were newly diagnosed with clinically localized prostate cancer and received either radical prostatectomy (n = 1156) or external beam radiotherapy (n = 435) were included in this study. A propensity score was used to balance the two treatment groups because they differed in some baseline characteristics. This score was used in multivariable cross-sectional and longitudinal regression analyses comparing the treatment groups. All statistical tests were two-sided. RESULTS: Almost 2 years after treatment, men receiving radical prostatectomy were more likely than men receiving radiotherapy to be incontinent (9.6% versus 3.5%; P:<.001) and to have higher rates of impotence (79.6% versus 61.5%; P:<.001), although large, statistically significant declines in sexual function were observed in both treatment groups. In contrast, men receiving radiotherapy reported greater declines in bowel function than did men receiving radical prostatectomy. All of these differences remained after adjustments for propensity score. The treatment groups were similar in terms of general health-related quality of life. CONCLUSIONS: There are important differences in urinary, bowel, and sexual functions over 2 years after different treatments for clinically localized prostate cancer. In contrast to previous reports, these outcome differences reflect treatment delivered to a heterogeneous group of patients in diverse health care settings. These results provide comprehensive and representative information about long-term treatment complications to help guide and inform patients and clinicians about prostate cancer treatment decisions.

Validation study of retrospective recall of disease-targeted function: results from the prostate cancer outcomes study.

OBJECTIVES: This was an ancillary methodological study within the Prostate Cancer Outcomes Study (PCOS) to assess the validity of 6-month retrospective recall of prediagnostic disease-targeted function among men diagnosed with prostate cancer. METHODS: A convenience sample of 133 prostate cancer cases were administered a baseline questionnaire shortly after diagnosis that asked about prediagnostic urinary, sexual, and bowel function. They were surveyed again concerning the same items 6 months later and asked to recall their prediagnostic function. Reports of prediagnostic function obtained at baseline and 6 months are compared, as are measures of change derived from these reports. Percent agreement and weighted kappas are calculated to measure the extent of agreement. RESULTS: Over 70% of the men reported prediagnostic functioning at the highest level on 12 of 17 survey items. For each of these items, recall at 6 months was identical to the baseline survey response for > or =69% of the men. The values of the weighted kappas for changes computed with baseline reports (prospective) and changes computed with 6-month recall (retrospective) ranged from 0.396 to 0.919 for the 17 individual items. Intraclass correlations for the retrospective versus prospective changes in the multi-item function scores were 0.828 for urinary, 0.618 for bowel, and 0.692 for sexual function. CONCLUSIONS: At baseline, men recently diagnosed with prostate cancer report few disease-related problems before diagnosis, and a high percentage of men recall this accurately 6 months later. There is reasonably high agreement between baseline and 6-month estimates of prediagnostic function and between prospective and retrospective measures of change over 6 months.

Who gets chemotherapy for metastatic lung cancer?

STUDY OBJECTIVES: To determine the prevalence and factors associated with chemotherapy use in elderly patients presenting with advanced lung cancer. DESIGN: A retrospective cohort study using administrative data. SETTING AND PATIENTS: We analyzed the medical bills for the 6,308 Medicare patients > 65 years old with diagnosed stage IV non-small cell lung cancer (NSCLC) in the 11 SEER (survival, epidemiology, and end results) regions between 1991 and 1993. The main outcome measure, chemotherapy administration, was identified by the relevant medical billing codes. Patient sociodemographic and disease characteristics were obtained from the SEER database and census data. RESULTS: Almost 22% of patients received chemotherapy at some time for their metastatic NSCLC. As expected, younger patients and those with fewer comorbid conditions were more likely to receive chemotherapy. However, several nonmedical factors, such as nonblack race, higher socioeconomic status, treatment in a teaching hospital, and living in the Seattle/Puget Sound or Los Angeles SEER regions, also significantly increased a patient's likelihood of receiving chemotherapy. CONCLUSION: Compared to previous reports, the prevalence of chemotherapy use for advanced NSCLC appears to be increasing. However, despite uniform health insurance coverage, there is wide variation in the utilization of palliative chemotherapy among Medicare patients, and nonmedical factors are strong predictors of whether a patient receives chemotherapy. While it is impossible to know the appropriate rate of usage, nonmedical factors should only influence a patient's likelihood of receiving treatment if they reflect patient treatment preference. Research to further clarify the costs, benefits, and patient preferences for chemotherapy in this patient population is warranted in order to minimize the effect of nonmedical biases on management decisions.

Use of preventive services by managed care enrollees: an updated perspective.

We examined whether enrollees in managed care plans received more preventive services than enrollees in non-managed care plans did, by conducting an updated literature synthesis of studies published between 1990 and 1998. We found that 37 percent of comparisons indicated that managed care enrollees were significantly more likely to obtain preventive services; 3 percent indicated that they were significantly less likely to do so; and 60 percent found no difference. Enrollees in group/staff-model health maintenance organizations (HMOs) were more likely to receive preventive services, but there was little evidence, outside of Medicaid managed care, that managed care plans are worse at providing preventive services. However, most of the evidence is equivocal: Provision of preventive services was neither better nor worse in managed versus non-managed care plans. Because of the blurred distinctions among types of health plans, more research is needed to identify which plan characteristics are most likely to encourage appropriate utilization.

Urinary and sexual function after radical prostatectomy for clinically localized prostate cancer: the Prostate Cancer Outcomes Study.

CONTEXT: Patients with prostate cancer and their physicians need knowledge of treatment options and their potential complications, but limited data on complications are available in unselected population-based cohorts of patients. OBJECTIVE: To measure changes in urinary and sexual function in men who have undergone radical prostatectomy for clinically localized prostate cancer. DESIGN: The Prostate Cancer Outcomes Study, a population-based longitudinal cohort study with up to 24 months of follow-up. SETTING: Population-based cancer registries in 6 geographic regions of the United States. PARTICIPANTS: A total of 1291 black, white, and Hispanic men aged 39 to 79 years who were diagnosed as having primary prostate cancer between October 1, 1994, and October 31, 1995, and who underwent radical prostatectomy within 6 months of diagnosis for clinically localized disease. MAIN OUTCOME MEASURES: Distribution of and change in urinary and sexual function measures reported by patients at baseline and 6, 12, and 24 months after diagnosis. RESULTS: At 18 or more months following radical prostatectomy, 8.4% of men were incontinent and 59.9% were impotent. Among men who were potent before surgery, the proportion of men reporting impotence at 18 or more months after surgery varied according to whether the procedure was nerve sparing (65.6% of non-nerve-sparing, 58.6% of unilateral, and 56.0% of bilateral nerve-sparing). At 18 or more months after surgery, 41.9% reported that their sexual performance was a moderate-to-large problem. Both sexual and urinary function varied by age (39.0% of men aged <60 years vs 15.3 %-21.7% of older men were potent at > or =18 months [P<.001]; 13.8% of men aged 75-79 years vs 0.7%-3.6% of younger men experienced the highest level of incontinence at > or =18 months [P = .03]), and sexual function also varied by race (38.4% of black men reported firm erections at > or =18 months vs 25.9% of Hispanic and 21.3% of white men; P = .001). CONCLUSIONS: Our study suggests that radical prostatectomy is associated with significant erectile dysfunction and some decline in urinary function. These results may be particularly helpful to community-based physicians and their patients with prostate cancer who face difficult treatment decisions.

Development of a comorbidity index using physician claims data.

Important comorbidities recorded on outpatient claims in administrative datasets may be missed in analyses when only inpatient care is considered. Using the comorbid conditions identified by Charlson and colleagues, we developed a comorbidity index that incorporates the diagnostic and procedure data contained in Medicare physician (Part B) claims. In the national cohorts of elderly prostate (n = 28,868) and breast cancer (n = 14,943) patients assessed in this study, less than 10% of patients had comorbid conditions identified when only Medicare hospital (Part A) claims were examined. By incorporating physician claims, the proportion of patients with comorbid conditions increased to 25%. The new physician claims comorbidity index significantly contributes to models of 2-year noncancer mortality and treatment received in both patient cohorts. We demonstrate the utility of a disease-specific index using an alternative method of construction employing study-specific weights. The physician claims index can be used in conjunction with a comorbidity index derived from inpatient hospital claims, or employed as a stand-alone measure.

Obtaining long-term disease specific costs of care: application to Medicare enrollees diagnosed with colorectal cancer.

OBJECTIVES: This study develops estimates of long-term, cancer-related treatment cost using a modeling approach and data from the SEER-Medicare linked database. The method is demonstrated for colorectal cancer. METHODS: Data on Medicare payments were obtained for colorectal cancer patients for the years 1990 to 1994 from the SEER-Medicare linked database. Claims payment data for control subjects were obtained for Medicare enrollees without cancer residing in the same areas as patients. Estimates of long-term cost (< or = 25 years following the date of diagnosis) were obtained by combining treatment/phase-specific cost estimates with estimates of long-term survival from SEER. Treatment phases were defined as initial care, terminal care, and continuing care. Cancer-related estimates for each phase were obtained by subtracting costs for control subjects from the observed costs for cancer patients, matching on age group, gender, and registry area. Estimates of long-term cost < or = 11 years obtained by this method were compared with 11-year estimates obtained by application of the Kaplan-Meier sample average (KMSA) method. RESULTS: The mean initial-phase cancer-related cost was approximately $18,000 but was higher among patients with more advanced cancer. The mean continuing-phase cancer-related cost was $1,500 per year and declined with increasing age, but was higher on an annual basis among persons with later stages of cancer and shorter survival time. The mean terminal-phase cancer-related cost was $15,000 and declined with both age at death and more advanced stage at diagnosis. After the phase-specific estimates were combined, the average long-term cancer-related cost was $33,700 ($31,300 at 3% discount rate) for colon cancer compared with $36,500 ($33,800 at 3% discount rate) for cancer of the rectum. This represented about half of the total long-term cost for Medicare enrollees diagnosed with this disease. Long-term cost was highest for Stage III cancer and lowest for in situ cancer. Eleven-year cancer-related costs estimated by the KMSA method were similar to estimates using the phase-based approach. CONCLUSIONS: This paper demonstrates that valid estimates of cancer-related long-term cost can be obtained from administrative claims data linked to incidence cancer registry data.

Prostate cancer treatment and ten-year survival among group/staff HMO and fee-for-service Medicare patients.

OBJECTIVE: To compare treatment patterns and the ten-year survival of prostate cancer patients in two large, nonprofit, group/staff HMOs to those of patients receiving care in the fee-for-service health setting. DATA SOURCES/STUDY DESIGN: A cohort of men age 65 and over diagnosed with prostate cancer between 1985 and the end of 1992 and followed through 1994. Subjects (n = 21,741) were ascertained by two population-based tumor registries covering the greater San Francisco-Oakland and Seattle-Puget Sound areas. Linkage of registry data with Medicare claims data and with HMO inpatient utilization data allowed the determination of health plan enrollment and the measurement of comorbid conditions. Multivariate regression models were used to examine HMO versus FFS treatment and survival differences adjusting for sociodemographic and clinical characteristics. PRINCIPAL FINDINGS: Among cases with non-metastatic prostate cancer, HMO patients were more likely than FFS patients to receive aggressive therapy (either prostatectomy or radiation) in San Francisco-Oakland (odds ratio [OR] = 1.69, 95% CI = 1.46-1.96) but not in Seattle (OR = 1.15, 0.93-1.43). Among men receiving aggressive therapy, HMO cases were three to five times more likely to receive radiation therapy than prostatectomy. Overall mortality was equivalent over ten years (HMO versus FFS mortality risk ratio [RR] = 1.01, 0.94-1.08), but prostate cancer mortality was higher for HMO cases than for FFS cases (RR = 1.25, 1.13-1.39). CONCLUSION: Despite marked treatment differences for clinically localized prostate cancer, overall ten-year survival for patients enrolled in two nonprofit group/staff HMOs was equivalent to survival among patients receiving care in the FFS setting, even after adjustment for sociodemographic and clinical characteristics. Similar overall but better prostate cancer-specific survival among FFS patients is most plausibly explained by differences between the HMO and FFS patients in both tumor characteristics and unmeasured patient selection factors.

Survival and treatment for colorectal cancer Medicare patients in two group/staff health maintenance organizations and the fee-for-service setting.

The current study compares treatment use and long-term survival in colorectal cancer patients between Medicare beneficiaries enrolled in two large prepaid group/staff health maintenance organizations (HMOs) and the fee-for-service (FFS) setting. The study is based on 15,352 colorectal cancer cases diagnosed between 1985 and 1992 and followed through 1995. Survival differences between the HMO and FFS cases were assessed using Cox regression. Treatment differences were evaluated using logistic regression. HMO cases had a lower overall mortality than did FFS cases but not a significantly lower colorectal cancer-specific mortality. Use of surgical resection was similar between HMO and FFS cases. However, rectal cancer cases in the HMOs were more likely to receive postsurgical radiation therapy than FFS cases. Superior overall survival in the HMOs may be the result of increased colorectal cancer screening, greater use of adjuvant therapies, and selection of healthier individuals.

Use of Medicare hospital and physician data to assess breast cancer incidence.

OBJECTIVES: Health claims data have the potential of being an inexpensive, timely, and nationally representative source of information about cancer. This study examined the utility of Medicare hospital and physician data as an independent source to identify incident breast cancer cases. METHODS: Data came from Medicare and the National Cancer Institute's SEER cancer registries. From 1992, for women residing in the SEER states (n = 659,260), Medicare hospital and physician claims were reviewed to identify women with a breast cancer diagnosis on a claim (n = 6,784). These women were matched with women in the SEER data who had been diagnosed with breast cancer in 1992 (n = 3,230). The sensitivity, specificity, and positive predictive value (PPV) of the Medicare data were calculated. Logistic regression models were used to identified cancer related procedures reported to Medicare that could distinguish true cases from false positive cases. Predicted values from these models were included to create plots of sensitivity versus false positive rates and sensitivity versus PPV. RESULTS: Medicare hospital data had 62% sensitivity, 99.9% specificity, and 88% PPV. Physician claims increased sensitivity by 14%, with specificity of 99.4%, and a PPV of 10%. Inclusion of additional cancer related diagnoses and procedures improved the ability to distinguish true cases from false positives, although the number of false positive cases remained high. CONCLUSIONS: The Medicare data overall offer limited potential to assess breast cancer incidence, largely because of low sensitivity and poor PPV. The Medicare data may have utility to identify women undergoing selected breast cancer treatments. In addition, the data may be used to help registries focus case-finding efforts, particularly for persons undergoing cancer related treatments.