Survival outcomes of patients with lobular carcinoma in situ who underwent bilateral mastectomy or partial mastectomy.

AIM: To compare the survival outcomes between patients treated with bilateral mastectomy and partial mastectomy alone as the initial surgical management for primary lobular carcinoma in situ (LCIS).

PATIENTS AND

METHODS

Patients with histologically confirmed LCIS underwent partial mastectomy alone or bilateral mastectomy were identified by the SEER*Stat database (version 8.3.2) released in 2016. The primary outcome measure was all-cause mortality and the secondary outcome measure was breast cancer-specific mortality.

RESULTS

Of the 5964 cases included in the analysis, 208 cases underwent bilateral mastectomy and 5756 cases underwent partial mastectomy alone. The 1-, 5- and 10-year estimated overall survival rates were 99.7%, 96.7% and 91.7%, respectively. Univariate and multivariate proportional hazards regression (Cox) analyses showed no significant difference between the risk of all-cause mortality in the bilateral mastectomy group compared with the partial mastectomy group (HR = 1.106, 95% confidence interval [CI] 0.350-3.500, P = 0.86). In propensity score-matched model, bilateral mastectomy still did not show benefit to overall mortality (HR = 2.248, 95% CI 0.451-11.200). Patients older than 60 years of age showed a higher risk of all-cause mortality (HR = 7.593, 95% CI 5.357-10.764, P < 0.0001). No risk factors, including surgery type, were identified for breast cancer-specific survival.

CONCLUSIONS

Survival outcomes of patients with LCIS who underwent partial mastectomy without radiotherapy were not inferior to patients who underwent bilateral prophylactic mastectomy. Breast cancer-specific mortality in patients with LCIS was extremely low; aggressive prophylactic surgery like bilateral prophylactic mastectomy should not be advocated for most patients with LCIS.