Delaying chemo for breast cancer reduces overall survival

Breast cancer patients who delay chemotherapy more than 90 days after surgery are one-third more likely to die within five years, compared to those who start chemo sooner. Triple-negative breast cancer patients who delay treatment have a more than 50 percent increased risk of death, according to a new MD Anderson study.

"Compared to patients who start chemotherapy during the first month after surgery, those who began chemo 30 to 90 days after surgery did not have adverse outcomes," said Mariana Chavez Mac Gregor, M.D., assistant professor of Health Services Research and Breast Medical Oncology at MD Anderson, and lead author of the study. "However, starting chemotherapy more than 90 days after surgery was associated with a statistically significant increase in the risk of death and breast cancer-specific death."

Chemotherapy is used after surgery to prevent remnants of tumors from growing or becoming drug-resistant. Although most patients start chemo 30 to 40 days after surgery, and the Centers for Medicare and Medicaid services considers starting within 120 days to be a "quality metric," Chavez Mac Gregor said there currently are no official guidelines recommending the optimal time to start chemo after surgery.

The study aims to change that, and suggests that all breast cancer patients receiving chemotherapy after surgery should do so within 90 days of surgery or 120 days of diagnosis, though optimally chemo treatment should not be delayed at all after surgery.

The authors also sought to determine factors such as socio-economic status and insurance coverage that can delay treatment. Worse overall survival was seen among black patients, those with a lower socio-economic status, and people using Medicare and Medicaid. Patients with later-stage and more serious types of cancer, however, had fewer delays.

"We need to identify the determinants of delays in treatment so we can act on them and potentially improve the delivery of care in vulnerable populations," Chavez Mac Gregor said. "In most clinical scenarios, administering chemotherapy within three months is more than feasible."

Learn more about the importance of timely chemotherapy on MD Anderson’s website.