Prognostic value of breast cancer subtypes on breast cancer specific survival, distant metastases and local relapse rates in conservatively managed early stage breast cancer: a retrospective clinical study

Aim: To ascertain if breast cancer subtypes had prognostic effect on breast cancer specific survival, distant metastases and local relapse rates in women affected by early stage breast cancer. Patients and methods: Data of 774 patients affected by early stage breast cancer and treated with breast-conserving therapy were reviewed. Patients were grouped, based on steroid receptor status and HER2 status as: Luminal A (ER+/PR+/HER2-), Luminal B (ER+/PR+/HER2+), Basal-like (ER-/PR-/HER2-) and HER2 (ER-/PR-/HER2+). Distribution of variables among subtypes was evaluated with Pearson's test. Survival rates were calculated with life tables; Cox regression stepwise method was used to identify predictive variables of survival. Results: Median age was 55.0 years old (range 27-80) and median follow up time of 59.0 months (range 13.6-109.7). Breast cancer specific survival and distant metastases rates were different among breast cancer subtypes (both outcomes P = 0.00001) but there was no difference regarding local relapse rates (P = 0.07). Axillary nodes status (P = 0.00001), adjuvant therapy (P = 0.03) and breast cancer subtypes (P = 0.03) resulted prognostic factors of breast cancer specific survival; axillary node status (P = 0.00001) and breast cancer subtypes (P = 0.00001) had an impact on distant metastases. Age (P = 0.003), tumor size (P = 0.0001), positive or close surgical margin (P = 0.00001) and tumor grade 3 (P = 0.049) resulted prognostic factors of local relapse. Conclusions: In our study, breast cancer subtype seems a prognostic factor of breast cancer specific survival and distant metastases rates, but not of local relapse rate. Patients could be submitted to conservative surgery, if feasible, but considering the differences in survivals, patients with worse prognosis should receive more aggressive adjuvant treatments.