Approxemately one half of patients 65 years of age and older with stage I to III breast cancer do not receive trastuzumab-based therapy, which includes many with locally advanced disease. Significant racial disparities exist in the receipt of this highly effective therapy. Further research that identifies barriers to use and increases uptake of trastuzumab could potentially improve recurrence and survival outcomes in this population, particularly among minority women.
Purpose The combination of chemotherapy and trastuzumab is the standard of care for adjuvant treatment of human epidermal growth factor receptor 2-positive breast cancer. Two regimens have been widely adopted in the United States: doxorubicin, cyclophosphamide, paclitaxel, and trastuzumab (ACTH) and docetaxel, carboplatin, and trastuzumab (TCH). No head-to-head comparison of these regimens has been conducted in a clinical trial, and existing trial data have limited generalizability to older patients. Methods We used SEER-Medicare data from 2005 to 2013 to compare outcomes of ACTH versus TCH among patients age older than 65 years. Propensity score matching was used to balance cohort characteristics between treatment arms. Outcomes included toxicity-related hospitalization, survival, and trastuzumab completion. Data from 1,077 patients receiving ACTH or TCH were analyzed, and the propensity-matched subsample included 416 women. Results There was a significant shift toward TCH over time, with 88% of patients receiving ACTH in 2005 compared with 15% by 2011. Among propensity score-matched patients, we found no difference between regimens in health care use overall or for chemotherapy-related adverse events (ACTH, 34% v TCH, 36.5%; P = .46). Patients receiving TCH were significantly more likely to complete trastuzumab (89% v 77%; P = .001). There was no difference in 5-year breast cancer-specific survival (ACTH, 92% v TCH, 96%; hazard ratio, 2.08; 95% CI, 0.90 to 4.82) or overall survival. Conclusion Among a matched sample of older patients, ACTH compared with TCH was not associated with a higher rate of serious adverse events or hospitalizations, but it was associated with less completion of adjuvant trastuzumab. We did not detect a difference in 5-year survival outcomes for ACTH compared with TCH. In the context of limited evidence in older patients, selection between these two regimens on the basis of concerns about differential toxicity or efficacy may not be appropriate.
Background
Adults ≥ 65 years dually enrolled in Medicare and Medicaid (Duals) are an at-risk group in healthcare, however outcomes of women with gynecologic cancers in this population are unknown.
Methods
This is a population-based cohort study of North Carolina state cancer registry cases of uterine, ovarian, cervical, and vulvar/vaginal cancers (2003-09), with linked enrollment in Medicare and state Medicaid. Outcomes of all-cause mortality and stage of diagnosis were analyzed as a function of enrollment status using multivariate analysis and survival curves.
Results
Of 4,522 women ≥ 65, (3,702 (82%) Medicare and 820 (18%) were Dually enrolled), there were 2286 (51%) uterine, 1587 (35%) ovarian, 302 (7%) cervix, and 347 (8%) vulvar/vaginal cancers. Dual enrollees had increased all-cause mortality overall (aHR 1.34, 95%CI 1.19–1.49), and within each cancer site: uterine aHR 1.22 (95%CI 1.02-1.47); ovarian aHR 1.25 (95%CI 1.05-1.49); cervical aHR 1.34 (95%CI 0.96–1.87); and vulvar/vaginal aHR 1.93 (95%CI 1.36–2.72). Increased odds of advanced stage disease at diagnosis among Dual enrollees was only present in uterine cancer (aOR 1.38, 95%CI 1.06–1.79). Stratified survival curves demonstrate the strongest disparities amongst women with early stage uterine and early stage vulvar/vaginal cancers.
Conclusions
Women ≥ 65 dually enrolled in Medicare and Medicaid have an overall 34% increase in all-cause mortality after diagnosis with a gynecologic cancer compared to the non-dual Medicare population. Women with early stage uterine and vulvar/vaginal cancers have the most disparate outcomes. As these malignancies are generally curable they have the most potential for benefit from targeted interventions.
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