The median age of the 24,843 patients at diagnosis was 53 and the median time to chemotherapy was 46 days. In the study, 21 percent of patients started chemotherapy within fewer than 31 days; 50 percent between 31 and 60 days after surgery; 19.2 percent between 61 and 90 days; 9.8 percent in 91 or more days after surgery.
The factors associated with delays in time to chemotherapy included low socioeconomic status, breast reconstruction, nonprivate insurance, and being Hispanic or black, according to the study.
Compared with patients who received chemotherapy within 31 days of surgery, the study reports no adverse outcomes were associated with time to chemotherapy of 31 to 90 days of surgery.
However, there was increased risk of worse overall survival and worse breast cancer-specific survival among patients treated with chemotherapy 91 or more days after surgery, the results indicate. The study suggests patients with a time to chemotherapy of 91 or more days, had a 34 percent increased risk of overall death and a 27 percent increased risk of death from breast cancer.
The authors note their study is limited by its retrospective nature, which uses historical data.
"Given the results of our analysis, we would suggest that all breast cancer patients that are candidates for adjuvant chemotherapy should receive this treatment within 91 days of surgery or 120 days from diagnosis. Administration of chemotherapy within this frame is feasible in clinical practice under most clinical scenarios, and as medical oncologists, we should make every effort not to delay the initiation of adjuvant chemotherapy. Furthermore, determinants of delay in TTC [time to chemotherapy] were sociodemographic in nature; better understanding and removing barriers to access of care in vulnerable populations should be a priority," the study concludes.