Survival after standard or oncoplastic breast-conserving surgery versus mastectomy for breast cancer

Abstract

Background: Recent evidence suggests a survival advantage after breast-conserving surgery compared with mastectomy. Previous studies have compared survival outcomes after standard breast-conserving surgery, but no studies have compared survival outcomes after oncoplastic breast-conserving surgery. The aim of this study was to compare survival outcomes after breast-conserving surgery + radiotherapy (and an oncoplastic breast-conserving surgery + radiotherapy subgroup) with those after mastectomy ± radiotherapy.

Methods: Patients diagnosed with primary invasive breast cancer between 1 January 2010 and 31 December 2019 were identified from a prospectively maintained National Cancer Registry. Overall survival and breast cancer-specific survival outcomes were analysed using Kaplan-Meier analysis and Cox regression analysis adjusting for patient demographics, tumour characteristics, and treatment adjuncts.

Results: A total of 14 182 patients were eligible (8537 patients underwent standard breast-conserving surgery + radiotherapy, 360 patients underwent oncoplastic breast-conserving surgery + radiotherapy, 2953 patients underwent mastectomy + radiotherapy, and 2332 patients underwent mastectomy - radiotherapy). The median follow-up was 7.27 (range 0.2-13.6) years. Superior 10-year survival was observed after breast-conserving surgery + radiotherapy (overall survival: 81.2%; breast cancer-specific survival: 93.3%) compared with mastectomy + radiotherapy (overall survival: 63.4%; breast cancer-specific survival: 75.9%) and mastectomy - radiotherapy (overall survival: 63.1%; breast cancer-specific survival: 87.5%). Ten-year overall survival and breast cancer-specific survival after oncoplastic breast-conserving surgery + radiotherapy were 86.1% and 90.2% respectively. After adjusted analysis, breast-conserving surgery + radiotherapy was associated with superior survival outcomes compared with mastectomy + radiotherapy (overall survival: HR 1.34 (95% c.i. 1.20 to 1.51); breast cancer-specific survival: HR 1.62 (95% c.i. 1.38 to 1.90)) and mastectomy - radiotherapy (overall survival: HR 1.57 (95% c.i. 1.41 to 1.75); breast cancer-specific survival: HR 1.70 (95% c.i. 1.41 to 2.05)). Similar survival outcomes were observed amongst patients treated with oncoplastic breast-conserving surgery + radiotherapy compared with mastectomy + radiotherapy (overall survival: HR 1.72 (95% c.i. 1.62 to 2.55); breast cancer-specific survival: HR 1.74 (95% c.i. 1.06 to 2.86)) and mastectomy - radiotherapy (overall survival: HR 2.21 (95% c.i. 1.49 to 3.27); breast cancer-specific survival: HR 1.89 (95% c.i. 1.13 to 3.14)).

Conclusion: Breast-conserving surgery + radiotherapy and oncoplastic breast-conserving surgery + radiotherapy are associated with superior overall survival and breast cancer-specific survival compared with mastectomy ± radiotherapy. The findings should inform discussion of surgical treatment options for patients with breast cancer.

Fig. 1.

CONSORT diagram for all breast cancer diagnoses in the West of Scotland between 2010 and 2019 WoSCAN, West of Scotland Cancer Network.

Fig. 2.

Kaplan–Meier survival curves comparing breast-conserving surgery + radiotherapy and mastectomy ± radiotherapy a Overall survival. b Breast cancer-specific survival. BCS, breast-conserving surgery; RTx, radiotherapy; MTx, mastectomy.

Fig. 3

Kaplan–Meier survival curves comparing oncoplastic breast-conserving surgery + radiotherapy and mastectomy ± radiotherapy a Overall survival. b Breast cancer-specific survival. OBCS, oncoplastic breast-conserving surgery; RTx, radiotherapy; MTx, mastectomy.

Fig. 4

Kaplan–Meier survival curves comparing standard breast-conserving therapy + radiotherapy and oncoplastic breast-conserving surgery + radiotherapy a Overall survival. b Breast cancer-specific survival. sBCS, standard breast-conserving surgery; RTx, radiotherapy; OBCS, oncoplastic breast-conserving surgery.