by M.G. Davey, C.M. Davey, É.J. Ryan, A.J. Lowery, M.J.
Kerin
The Breast: February 04,
2021
Background
The non-inferiority of combined breast conservation surgery
(BCS) and radiotherapy (breast conservation therapy or BCT) compared to
mastectomy in sporadic breast cancer cases is well recognised. Uncertainty
remains regarding optimal surgical practice in BRCA mutation carriers.
Aims
To evaluate the oncological safety of combined BCT versus
mastectomy in BRCA mutation carriers following breast cancer diagnosis.
Methods
A systematic review was performed as per PRISMA and MOOSE guidelines.
Observational studies comparing BCS and mastectomy in BRCA carriers were
identified. Dichotomous variables were pooled as odds ratios (OR) using the
Mantel–Haenszel method. Log hazard ratios (lnHR) for locoregional recurrence
(LRR), contralateral breast cancer, disease-free and overall survival and their
standard errors were calculated from Kaplan-Meier or cox-regression analyses
and pooled using the inverse variance method.
Results
Twenty three studies of 3,807 patients met inclusion
criteria; 2,200 (57.7%) were BRCA1 and 1212 (31.8%) were BRCA2 carriers. Median
age at diagnosis was 41 years with 96 months follow up. BCS was performed on
2157 (56.7%) while 1408 (41.5%) underwent mastectomy. An increased risk of LRR
was observed in patients treated with BCS (HR:4.54, 95% Confidence Interval:
2.77-7.42, P<0.001, heterogeneity (I2)=0%). However, the risks of
contralateral breast cancer (HR:1.51, 95%CI: 0.44-5.11, P=0.510, I2=80%),
disease recurrence (HR:1.16, 95%CI: 0.78-1.72, P=0.470, I2=44%), disease-specific
recurrence (HR:1.58, 95%CI: 0.79-3.15, P=0.200, I2=38%) and death
(HR:1.10, 95%CI: 0.72-1.69, P=0.660, I2=38%) were equivalent for
combined BCT and mastectomy.
Conclusions
Survival outcomes following combined BCT is comparable to
mastectomy in BRCA carriers. However, the risk of LRR is increased. Patient
counselling should be tailored to incorporate these findings.
