Comparison of Survival After Breast-Conserving Therapy vs Mastectomy Among Patients With or Without the <i>BRCA1/2</i> Variant in a Large Series of Unselected Chinese Patients With Breast Cancer
Authors: Qiting Wan, Liming Su, Tao Ouyang, Jinfeng Li, Tianfeng Wang, Zhaoqing Fan, Tie Fan, Benyao Lin, Yuntao Xie
Journal: JAMA Network Open (2021)

<h3>Importance</h3> Whether patients with breast cancer who carry a<i>BRCA1/2</i>variant can safely undergo breast-conserving therapy (BCT) remains controversial. <h3>Objective</h3> To compare survival rates after BCT vs mastectomy in<i>BRCA1/2</i>variant carriers and noncarriers in a large series of unselected patients with breast cancer. <h3>Design, Setting, and Participants</h3> In this cohort study, a large consecutive series of 8396 unselected patients with primary breast cancer underwent either BCT, mastectomy with radiotherapy, or mastectomy alone from October 1, 2003, to May 31, 2015, at the Breast Center of Peking University Cancer Hospital in China. All patients were assessed for<i>BRCA1/2</i>germline variant status. Statistical analysis was performed from May 1 to September 30, 2020. <h3>Main Outcomes and Measures</h3> The primary outcomes were breast cancer–specific survival (BCSS) and overall survival (OS); secondary outcomes included recurrence-free survival, distant recurrence–free survival, and ipsilateral breast tumor recurrence. <h3>Results</h3> Of these 8396 Chinese patients (8378 women [99.8% women]; mean [SD] age, 50.8 [11.4] years; 187<i>BRCA1</i>carriers, 304<i>BRCA2</i>carriers, and 7905 noncarriers), 3135 (37.3%) received BCT, 1511 (18.0%) received mastectomy with radiotherapy, and 3750 (44.7%) received mastectomy alone. After a median follow-up of 7.5 years (range, 0.3-16.6 years), both<i>BRCA1</i>and<i>BRCA2</i>variant carriers treated with BCT had similar rates of survival compared with those treated with mastectomy with radiotherapy (BCSS: hazard ratio [HR] for<i>BRCA1</i>, 0.58 [95% CI, 0.16-2.10];<i>P</i> = .41; HR for<i>BRCA2</i>, 0.46 [95% CI, 0.15-1.41];<i>P</i> = .17; OS: HR for<i>BRCA1</i>, 0.61 [95% CI, 0.18-2.12];<i>P</i> = .44; HR for<i>BRCA2</i>, 0.72 [95% CI, 0.26-1.96];<i>P</i> = .52) or mastectomy alone (BCSS: HR for<i>BRCA1</i>, 0.70 [95% CI, 0.22-2.20];<i>P</i> = .54; HR for<i>BRCA2</i>, 0.59 [95% CI, 0.18-1.93];<i>P</i> = .39; OS: HR for<i>BRCA1</i>, 0.77 [95% CI, 0.27-2.21];<i>P</i> = .63; HR for<i>BRCA2</i>, 0.62 [95% CI, 0.22-1.73];<i>P</i> = .37) after adjusting for clinicopathologic factors and adjuvant therapy. For noncarriers, patients receiving BCT had significantly better survival than those receiving mastectomy with radiotherapy (BCSS: HR, 0.45 [95% CI, 0.36-0.57];<i>P</i> &lt; .001; OS: HR, 0.46 [95% CI, 0.37-0.58];<i>P</i> &lt; .001) or mastectomy alone (BCSS: HR, 0.71 [95% CI, 0.57-0.89];<i>P</i> = .003; OS: HR, 0.71 [95% CI, 0.58-0.87];<i>P</i> &lt; .001) in multivariable analyses. <h3>Conclusions and Relevance</h3> This study suggests that<i>BRCA1/2</i>variant carriers treated with BCT have survival rates at least comparable to those treated with mastectomy with radiotherapy or mastectomy alone and that BCT could be an option for<i>BRCA1/2</i>variant carriers when the tumor is clinically appropriate for BCT.