Delayed Adjuvant Chemotherapy Significantly Affects Breast Cancer Recovery

In an observational, population-based, investigational study published in JAMA online, researchers from University of Texas MD Anderson Cancer Center in Houston and the Cancer Prevention Institute of California in Fremont hypothesized that prolonged time to chemotherapy (TTC) would be associated with adverse outcomes. Data from the California Cancer Registry were used to study 24,843 patients with stage I to stage III invasive breast cancer who were diagnosed between January 1, 2005, and December 31, 2010.

The use of adjuvant chemotherapy has had a significant effect in decreasing the risk of reoccurrence and in improving survival rates among patients with early-stage breast cancer, said the researchers. Delaying adjuvant chemotherapy beyond the typical start of 30 to 40 days of surgery could decrease the benefits provided by cytotoxic systemic therapies.

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Researchers gathered patient information, including demographic characteristics (age, race, marital status, insurance type), other variables related to the cancer diagnosis and treatment, and data on patient’s tumor estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (ERBB2) status. The participants were categorized into subgroups according to breast cancer subtype and TTC categories of ≤ 30 days, 31 to 60 days, 61 to 90 days, or ≥ 90 days. Ninety-one or more days from surgery to the first diagnosis of adjuvant chemotherapy was considered a delay.

After evaluating all the factors associated with a delay in adjuvant chemotherapy administration, the researchers observed that compared with stage I patients those with stage II and stage III were less likely to have delays in chemotherapy administration. It was also found that patients with triple-negative breast cancer (TNBC) were less likely to have delays compared with patients with hormone-receptor positive tumors. Other factors associated with delays in TTC included low socioeconomic status (SES), breast reconstruction, nonprivate insurance, and ethnicity.

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Data from the analysis also showed that patients who received chemotherapy ≥ 91 days after surgery had worse overall survival (OS) along with patients with hormone-receptor positive and TNBC who were treated within the same time frame. Older age, advanced-stage breast cancer, ethnicity, lower SES, and type of insurance coverage also contributed to worse OS.

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As a result of the analysis, the researchers suggest all breast cancer patients who are candidates for adjuvant chemotherapy should receive treatment within 9 days of surgery or 120 days from diagnosis. Better understanding and removing socioeconomic barriers to access of care should also be a priority for health care providers.

Source: Chavez-MacGregor M, Clarke CA, Lichtensztajin DY, et al. Delayed initiation of adjuvant chemotherapy among patients with breast cancer. JAMA Oncol. 2015; doi: 10.10 01/jamaoncol. 2015.3856 [Published online December 10, 2015].