Association between initiation of adjuvant chemotherapy beyond 30 days after surgery and overall survival among patients with triple‐negative breast cancer

• Published in: International journal of cancer Vol. 147; no. 1; pp. 152 - 159
• Main Authors: Heeg, Erik, Marang‐van de Mheen, Perla J., Van Maaren, Marissa C., Schreuder, Kay, Tollenaar, Rob A.E.M., Siesling, Sabine, Bos, Monique E.M.M., Vrancken Peeters, Marie‐Jeanne T.F.D.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01-07-2020
• Subjects: Adult; Aged; breast cancer; Cancer Therapy and Prevention; Chemotherapy, Adjuvant - statistics & numerical data; Cohort Studies; delayed chemotherapy; Humans; Mastectomy - methods; Mastectomy - statistics & numerical data; Mastectomy, Segmental - methods; Mastectomy, Segmental - statistics & numerical data; Middle Aged; Netherlands - epidemiology; overall survival; Propensity Score; Registries; Time-to-Treatment - statistics & numerical data; Triple Negative Breast Neoplasms - drug therapy; Triple Negative Breast Neoplasms - mortality; Triple Negative Breast Neoplasms - surgery; Triple Negative Breast Neoplasms - therapy; triple‐negative; Netherlands; overall survival; breast cancer; delayed chemotherapy; triple-negative
• ISSN: 0020-7136; 1097-0215
• DOI: 10.1002/ijc.32788

Delayed time to chemotherapy (TTC) is associated with decreased outcomes of breast cancer patients. Recently, studies suggested that the association might be subtype‐dependent and that TTC within 30 days should be warranted in patients with triple‐negative breast cancer (TNBC). The aim of the current study is to determine if TTC beyond 30 days is associated with reduced 10‐year overall survival in TNBC patients. We identified all TNBC patients diagnosed between 2006 and 2014 who received adjuvant chemotherapy in the Netherlands. We distinguished between breast‐conserving surgery (BCS) vs. mastectomy given the difference in preoperative characteristics and outcomes. The association was estimated with hazard ratios (HRs) using propensity‐score matched Cox proportional hazard analyses. In total, 3,016 patients were included. In matched patients who underwent BCS (n = 904), 10‐year overall survival was favorable for patients with TTC within 30 days (84.4% vs. 76.9%, p = 0.001). Patients with TTC beyond 30 days were more likely than those with TTC within 30 days to die within 10 years after surgery (HR 1.69 (95% CI 1.22–2.34), p = 0.002). In matched patients who underwent mastectomy (n = 1,568), there was no difference in 10 years overall survival between those with TTC within or beyond 30 days (74.5% vs. 74.7%, p = 0.716), nor an increased risk of death for those with TTC beyond 30 days (HR 1.04 (95% CI 0.84–1.28), p = 0.716). Initiation of adjuvant chemotherapy beyond 30 days is associated with decreased 10 years overall survival in TNBC patients who underwent BCS. Therefore, timelier initiation of chemotherapy in TNBC patients undergoing BCS seems warranted.
What's new?
Current breast cancer treatment guidelines recommend that chemotherapy is initiated between 6‐12 weeks after surgery. Delayed treatment can lead to poorer outcome, but there's no precise definition of the optimal window. Recent work suggests that for patients with triple negative breast cancer (TNBC), it's best to initiate chemotherapy within 30 days. Here, the authors evaluated outcomes for TNBC patients correlated with time to chemotherapy. They found that in patients undergoing breast‐conserving surgery, an interval of more than 30 days before chemotherapy was associated with decreased survival. If the patient had undergone a mastectomy, a longer delay before chemotherapy did not impact survival.