The role of tumor phenotype in the surgical treatment of early-stage breast cancer

Background: We investigated whether tumor phenotype influences surgical decision-making, and how that may impact overall survival (OS) for early-stage breast cancer. Methods: Women aged 18-69 with cT0-2/cN0/cM0 breast cancer in the National Cancer Database (2010-2017) were included. A generalized logistic model was used to identify factors associated with surgery type. A Kaplan-Meier curve was used to visualize unadjusted OS, and the log-rank test was used to test for differences in OS between surgery types. Results: Of 597,149 patients, 58% underwent lumpectomy with radiation (BCT), 25% unilateral mastectomy (UM), and 17% bilateral mastectomy (BM). After adjustment, HER2+ and triple-negative (TN) tumors were less likely to undergo UM than BCT, versus hormone receptor-positive tumors (OR = 0.881, 95% CI = 0.860-0.903; OR = 0.485, 95% CI = 0.470-0.501). UM and BM had worse 5-year OS versus BCT (UM: 0.926, vs BM: 0.952, vs BCT: 0.960). Conclusions: BCT is increasingly used to treat HER2+ and TN tumors. More extensive surgery is not associated with better survival outcomes, regardless of tumor phenotype.

Automated summary

This study investigated the impact of tumor phenotype on surgical decision-making and overall survival in early-stage breast cancer. The study found that HER2+ and triple-negative tumors were less likely to undergo unilateral mastectomy compared to hormone receptor-positive tumors. Unilateral and bilateral mastectomy had worse 5-year overall survival compared to breast-conserving surgery. In conclusion, more extensive surgery did not result in better survival outcomes regardless of tumor phenotype.