Positive or close margins: reoperation rate and second conservative resection or total mastectomy?

Reoperation after breast-conserving surgery (BCS) could be proposed for positive or close margins. Reoperation type, re-excision or mastectomy, depends on several factors in relation to patient's and tumor's characteristics. We have analyzed our breast cancer (BC) database in order to determine second and third attempts for BCS and mastectomy rates, as well as associated factors for type of surgery.

All patients with BCS between 1995 and 2017 were included. Patient's characteristics, pathologic results, and treatments were analyzed. Reoperation rate, type of reoperation, second reoperation, and associated factors of reoperation, mastectomy, and third intervention were determined. Three periods were determined: P1-P3.

We analyzed 10,761 patients: 1,161 with ductal carcinoma in situ (DCIS) and 9,600 with invasive BC. The reoperation rate was 41.4% for DCIS and 28.0% for invasive BC. Using multivariate analysis, we identified tumor size >20 mm as being a risk factor for reoperation, whereas age >50 years, P2-3, and some localization decreased reoperation rates. For invasive BC, age >40 years, triple-negative tumors, neoadjuvant chemotherapy, and noncentral tumors decreased reoperation rates and lobular tumor, multifocal tumors, lymphovascular invasion, DCIS component, and Her2-positive tumors increased reoperation rates. For patients requiring reoperation, re-excision was performed in 48.1% (1,523/3,168) and mastectomy was required after first re-excision in 13.46% (205/1,523). For DCIS, mastectomy rates were higher for grade 2 and tumor ≥20 mm. For invasive BC, mastectomy rates were higher for lobular, multifocal, ≥20 mm, Her2-positive tumors and diffuse positive margins and lower for age >50 years and during the last period. Even if interval time between surgery and adjuvant treatments was higher for patients with reoperation, survival rates were not different between patients with and without reoperation.

A decrease in reoperation and mastectomy rates had been reported with several associated factors. A third intervention with mastectomy was required in 13.5% of patients. This information should be done in case of reoperation.