Radiotherapy is recommended for hormone receptor-negative older breast cancer patients after breast conserving surgery

Abstract

In this study, the necessity of radiotherapy (RT) for hormone receptor-negative older breast cancer patients after breast-conserving surgery (BCS) was investigated. The data of hormone receptor-negative invasive breast cancer patients who underwent BCS were extracted from the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2015. All patients were separated into two groups, namely, the RT group and the no radiotherapy (No RT) group. The 3- and 5-year overall survival (OS) and cancer-specific survival (CSS) rates were compared between the No RT and RT groups after propensity score matching (PSM). The nomograms for predicting the survival of patients were constructed from variables identified by univariate or multivariate Cox regression analysis. A total of 2504 patients were enrolled in the training cohort, and 630 patients were included in the validation cohort. After PSM, 738 patients were enrolled in the No RT group and RT group. We noted that RT can improve survival in hormone receptor-negative older breast cancer patients who undergo BCS. Based on the results of multivariate Cox analysis, age, race, tumour grade, receipt of RT and chemotherapy, pathological T stage, N status, M status and HER2 status were linked to OS and CSS for these patients, and nomograms for predicting OS and CSS were constructed and validated. Moreover, RT improved OS and CSS in hormone receptor-negative older breast cancer patients who underwent BCS. In addition, the proposed nomograms more accurately predicted OS and CSS for hormone receptor-negative older breast cancer patients after BCS.

Keywords: Breast conserving surgery; Hormone receptor-negative older breast cancer patients; Nomograms; Prognosis; Radiotherapy.

Figure 1

Overall survival analysis of patients in the RT group and non-RT group according to stratified analysis. (A) Age between 70 and 80 years; (B) age more than 80 years; (C) Grade I–II; (D) Grade III–IV; (E) HER2-negative; (F) HER2-positive; (G) T1; (H) T2; (I) T3-4; (J) negative lymph node; (K) positive lymph node; (L) M0; (M) M1; (N) without CT; (O) with CT. RT, radiotherapy; CT, chemotherapy

Figure 2

Cancer specific survival analysis of patients in the RT group and non-RT group according to stratified analysis. (A) Age between 70 and 80 years; (B) age more than 80 years; (C) Grade I–II; (D) Grade III–IV; (E) HER2-negative; (F) HER2-positive; (G) T1; (H) T2; (I) T3-4; (J) negative lymph node; (K) positive lymph node; (L) M0; (M) M1; (N) without CT; (O) with CT.

Figure 3

Risk factors related to overall survival identified by (A) univariate and (B) multivariate Cox regression analysis in the training cohort.

Figure 4

Risk factors related to cancer specific survival identified by (A) univariate and (B) multivariate Cox regression analysis in the training cohort.

Figure 5

Nomograms for predicting 3- and 5- year (A) overall survival and (B) cancer specific survival of hormone receptor-negative older breast cancer patients after breast conserving surgery.

Figure 6

The time-dependent receiver operating characteristic curves of the nomogram predicting (A) 3- and 5-year overall survival in the training cohort; (B) 3- and 5-year cancer specific survival in the training cohort; (C) 3- and 5-year overall survival in the validating cohort; (D) 3- and 5-year cancer specific survival in the validating cohort.

Figure 7

The calibration curves of the nomogram for predicting (A) 3- and 5-year overall survival in the training cohort; (B) 3- and 5-year cancer specific survival in the training cohort; (C) 3- and 5-year overall survival in the validating cohort; (D) 3- and 5-year cancer specific survival in the validating cohort.

Figure 8

The decision curve analysis of the nomograms and AJCC 7th stage model for predicting (A) 3-year OS; (B) 5-year OS; (C) 3-year CSS and (B) 5-year CSS of the training and validating cohort.