Neoadjuvant chemotherapy and short-term morbidity in patients undergoing mastectomy with and without breast reconstruction.

IMPORTANCE Neoadjuvant chemotherapy (NC) is increasingly being used in patients with breast cancer, and evidence-based reports related to its independent effects on morbidity after mastectomy with immediate breast reconstruction are limited. OBJECTIVE To determine the effect of NC on 30-day postoperative morbidity in women undergoing mastectomy with or without immediate breast reconstruction. DESIGN, SETTING, AND PARTICIPANTS All women undergoing mastectomy with or without immediate breast reconstruction from January 1, 2005, through December 31, 2011, at university and private hospitals internationally were analyzed using the American College of Surgeons National Surgical Quality Improvement Program 2005-2011 databases. Patients who received NC were compared with those without a history of NC to estimate the relative odds of 30-day postoperative overall, systemic, and surgical site morbidity using model-wise multivariable logistic regression. EXPOSURE Neoadjuvant chemotherapy. MAIN OUTCOMES AND MEASURES Thirty-day postoperative morbidity (overall, systemic, and surgical site). RESULTS Of 85,851 women, 66,593 (77.6%) underwent mastectomy without breast reconstruction, with 2876 (4.3%) receiving NC; 7893 patients were excluded because of missing exposure data. The immediate breast reconstruction population included 19,258 patients (22.4%), with 820 (4.3%) receiving NC. After univariable analysis, NC was associated with a 20% lower odds of overall morbidity in the group undergoing mastectomy without breast reconstruction (odds ratio [OR], 0.80; 95% CI, 0.71-0.91) but had no significant effect in the immediate breast reconstruction group (OR, 0.98; 95% CI, 0.79-1.23). After adjustment for confounding, NC was independently associated with lower overall morbidity in the group undergoing mastectomy without breast reconstruction (OR, 0.61; 95% CI, 0.51-0.73) and the immediate tissue expander reconstruction subgroup (OR, 0.49; 95% CI, 0.30-0.84). Neoadjuvant chemotherapy was associated with decreased odds of systemic morbidity in 4 different populations: complete sample (OR, 0.59; 95% CI, 0.49-0.71), mastectomy without breast reconstruction (OR, 0.59; 95% CI, 0.48-0.72), any immediate breast reconstruction (OR, 0.57; 95% CI, 0.37-0.88), and the tissue expander subgroup (OR, 0.41; 95% CI, 0.23-0.72). CONCLUSIONS AND RELEVANCE Our study supports the safety of NC in women undergoing mastectomy with or without immediate breast reconstruction. Neoadjuvant chemotherapy is associated with lower overall morbidity in the patients undergoing mastectomy without breast reconstruction and in those undergoing tissue expander breast reconstruction. In addition, the odds of systemic morbidity were decreased in patients undergoing mastectomy with and without immediate breast reconstruction. The mechanisms behind the protective association of NC remain unknown and warrant further investigation.