Delaying chemotherapy after surgery in patients with breast cancer reduces survival.

Abstract

Delaying chemotherapy more than 90 days after surgery for breast cancer may significantly increase the risk of death, particularly among patients with triple-negative breast cancer (TNBC), according to a new study from The University of Texas MD Anderson Cancer Center in Houston.1 Currently, there are no guidelines recommending the optimal time to the initiation of adjuvant chemotherapy. For certain patients, the Centers for Medicare and Medicaid Services uses the administration of adjuvant chemotherapy within 120 days of diagnosis as a quality metric. The University of Texas MD Anderson Cancer Center and 10 other cancer hospitals are now reporting on this metric. The authors of the current study found that the factors contributing to delayed treatment were socioeconomic status, insurance coverage, and ethnicity. They found that patients who initiate chemotherapy more than 90 days after surgery are 34% more likely to die within 5 years, and patients with TNBC who delay treatment have a 53% increased risk of death. Lead author Mariana Chavez MacGregor, MD, assistant professor of health services research and breast medical oncology, notes that although adjuvant chemotherapy given after primary surgery has been shown to decrease the risk of recurrence and death, delaying the start of it may allow small remnants of the tumor to grow or become drug-resistant. The population-based study assessed data from 24,823 patients with stage I to III invasive breast cancer diagnosed between January 1, 2005, and December 31, 2010, who were treated with adjuvant chemotherapy. The study is the largest investigating delayed chemotherapy initiation with contemporary treatment regimens. Investigators found that compared with patients starting chemotherapy in the first month after surgery, those who initiated the treatment between 30 and 90 days after surgery did not have adverse outcomes. However, those patients who started chemotherapy 90 days after surgery had a statistically significant increase in the risk of death and breast cancer-specific death. The latter patients (9.8% of all participants) were 34% more likely to die within 5 years and 27% more likely to die from breast cancer in that time frame in comparison with patients who received chemotherapy within 30 days of surgery. Researchers also analyzed the data by breast cancer subtype. For patients with TNBC, a delay of more than 90 days was associated with a 53% increase in the risk of death. There was no significant effect from delay for those with hormone receptor–positive or human epidermal growth factor receptor 2–positive breast cancers. As a result of the findings, study senior author Sharon Giordano, MD, MPH, professor and chair of health services research, concludes that timely initiation of chemotherapy is particularly important for patients with TNBC. Among the factors contributing to the delayed administration of chemotherapy were increased age, reconstructive surgery, and low sociodemographic status. Patients without private insurance and those of Hispanic or African American descent were more likely to experience treatment delays. Patients receiving care at NCI-designated cancer centers had a 34% lower risk of death in comparison with those treated elsewhere. The authors note that in most clinical situations, starting chemotherapy within 3 months is more than feasible. All patients with breast cancer who receive adjuvant chemotherapy should do so within 90 days of surgery or 120 days of diagnosis, say the authors.