Background: Delay in the diagnosis of breast cancer is associated with worse stage distribution at diagnosis and decreased survival. However, the occurrence of delay in the delivery of adjuvant therapy and its impact on prognosis is not well understood.
Methods: To investigate the timeliness of initiation of adjuvant chemotherapy following surgery for breast cancer, we used data from the Surveillance, Epidemiology, and End-Results (SEER)-Medicare database. Among women > or = 65 years diagnosed between 1992 and 1999 with stages I-II breast cancer, we used linear regression and Cox proportional hazards models to investigate the time intervals between surgery and initiation of adjuvant chemotherapy, factors associated with delay, and the effect of delay on survival.
Results: Our sample consisted of 5003 women who received adjuvant chemotherapy. Of these, 47% initiated chemotherapy within 1 month, 37% between 1 and 2 months, 6% between 2 and 3 months and 10% >3 months (delay) following surgery. Delay was associated with increasing age, residing in a rural location, being unmarried, earlier tumor stage, hormone receptor positivity, mastectomy, and non-receipt of radiation therapy. Survival did not differ among patients who initiated chemotherapy within 1, 2, or 3 months after surgery. Delay beyond 3 months was, however, associated with increased disease-specific mortality (HR 1.69; 95% CI 1.31-2.19) and overall mortality (HR 1.46; 95% CI 1.21-1.75).
Conclusions: Among older patients, moderate delays in the receipt of adjuvant chemotherapy occur frequently, but long delays (>3 months) are uncommon. While early initiation of therapy is no benefit, significant delays are associated with increased mortality. Whether this reflects the medical impact of the delay of chemotherapy or factors associated with delay is unclear, but until this is clarified, patients should be encouraged to initiate treatment without significant delay.