Purpose: Black women with breast cancer are known to have poorer survival than white women. Suboptimal treatment may compromise the survival benefits of adjuvant chemotherapy. We analyzed the association of race and survival with duration of treatment and number of treatment cycles among women receiving chemotherapy for early-stage breast cancer.
Patients and methods: Patients were women in the Henry Ford Health System tumor registry who were diagnosed with stage I/II breast cancer between January 1, 1996, and December 31, 2001, who received adjuvant chemotherapy. We calculated an observed/expected ratio of treatment duration and of completed chemotherapy cycles for each patient. Using Cox proportional hazards models, we analyzed the association of early treatment termination and treatment duration with all-cause mortality, controlling for age, race, stage, hormone receptor status, grade, comorbidity score, and doxorubicin use.
Results: Of 472 eligible patients, 28% (31% black, 23% white; P = .03) received fewer cycles of treatment than expected. Black race, receipt of < or = 75% of the expected number of cycles, increasing age, hormone receptor negativity, and a comorbidity score of more than 1 were associated with poorer survival. Among the 344 patients receiving the expected number of cycles, 60% experienced delays. These delays did not reduce survival.
Conclusion: This study is the first to find that a substantial fraction of women with early-stage breast cancer terminated their chemotherapy prematurely and that early termination was associated with both black race and poorer survival. A better understanding of the determinants of suboptimal treatment may lead to interventions that can reduce racial disparities and improve breast cancer outcomes for all women.