Impact of Delayed Neoadjuvant Systemic Chemotherapy on Overall Survival Among Patients with Breast Cancer

Abstract

Background: Delays in the initiation of therapy among patients with early stage breast cancer (BC) can negatively affect outcomes. Patients treated with neoadjuvant systemic chemotherapy (NSC) usually display tumors with high-risk features. Considering these high-risk characteristics and the evidence supporting adverse outcomes associated with delays in adjuvant chemotherapy initiation, we sought to determine whether a delay in NSC initiation is associated with overall survival (OS).

Methods: We identified patients diagnosed between January 1995 and December 2015 with invasive primary BC (stage I-III) who received NSC at MD Anderson Cancer Center. Patients were categorized according to their time from BC diagnosis to NSC (in days) into three subgroups: 0-30, 31-60, and ≥61 days. Primary endpoint was OS. Descriptive statistics and Cox's proportional hazard models were used.

Results: A total of 5,137 patients were included. Median follow-up was 6.5 years. The 5-year OS estimates according to time to NSC were 87%, 85%, and 83% in patients who received NSC within 0-30, 31-60, and ≥61 days after diagnosis, respectively (p = .006). In multivariable analysis, compared with time to NSC of 0-30 days, delayed NSC ≥61 days was associated with an increased risk of death (31-60 days: hazard ratio [HR] = 1.05 [95% confidence interval (CI) 0.92-1.19]; ≥61 days, HR = 1.28 [95% CI 1.06-1.54]). In stratified analyses, the association between delay in NSC initiation and increased risk of death was statistically significant for patients with stage I and II BC (31-60 days: HR = 1.22 [95% CI 1.02-1.47]; ≥61 days, HR = 1.41 [95% CI 1.07-1.86]) and among patients with HER2-positive tumors ( ≥61 days, HR = 1.86 [95% CI 1.21-2.86]).

Conclusion: A delay in NSC initiation of more than 61 days after BC diagnosis was associated with an increased risk of death. Early initiation of NSC should be a priority; multidisciplinary teams must focus on coordination of care and patient-centered, timely treatment planning and delivery.

Implications for practice: The results of this study showed that a delay in neoadjuvant systemic chemotherapy initiation of more than 61 days after breast cancer diagnosis is associated with an increased risk of death; therefore, efforts must focus on early initiation of therapy, which should be a priority. Multidisciplinary teams must enhance coordination of care and patient-centered, timely treatment planning and delivery.

Keywords: Locoregional breast cancer; Neoadjuvant chemotherapy; Time to systemic therapy.

Figure 1

Time to neoadjuvant systemic chemotherapy according to year of diagnosis.

Figure 2

Kaplan‐Meier estimates of overall survival according to time to neoadjuvant systemic chemotherapy. Abbreviation: NST, neoadjuvant systemic therapy.