Nationwide population-based study of the impact of immediate breast reconstruction after mastectomy on the timing of adjuvant chemotherapy

Abstract

Background Initiation of adjuvant chemotherapy within 6-12 weeks after mastectomy is recommended by guidelines. The aim of this population-based study was to investigate whether immediate breast reconstruction (IBR) after mastectomy reduces the likelihood of timely initiation of adjuvant chemotherapy. Methods All patients with breast cancer who had undergone mastectomy and adjuvant chemotherapy between 2012 and 2016 in the Netherlands were identified. Time from surgery to adjuvant chemotherapy was categorized as within 6 weeks or after more than 6 weeks, within 9 weeks or after more than 9 weeks, and within 12 weeks or after more than 12 weeks. The impact of IBR on the initiation of adjuvant chemotherapy for these three scenarios was estimated using propensity score matching to adjust for treatment by indication bias. Results A total of 6300 patients had undergone primary mastectomy and adjuvant chemotherapy, of whom 1700 (27 center dot 0 per cent) had received IBR. Multivariable analysis revealed that IBR reduced the likelihood of receiving adjuvant chemotherapy within 6 weeks (odds ratio (OR) 0 center dot 76, 95 per cent c.i. 0 center dot 66 to 0 center dot 87) and 9 weeks (0 center dot 69, 0 center dot 54 to 0 center dot 87), but not within 12 weeks (OR 0 center dot 75, 0 center dot 48 to 1 center dot 17). Following propensity score matching, IBR only reduced the likelihood of receiving adjuvant chemotherapy within 6 weeks (OR 0 center dot 95, 0 center dot 90 to 0 center dot 99), but not within 9 weeks (OR 0 center dot 97, 0 center dot 95 to 1 center dot 00) or 12 weeks (OR 1 center dot 00, 0 center dot 99 to 1 center dot 01). Conclusion Postmastectomy IBR marginally reduced the likelihood of receiving adjuvant chemotherapy within 6 weeks, but not within 9 or 12 weeks. Thus, IBR is not contraindicated in patients who need adjuvant chemotherapy after mastectomy.