biostudies-literatureAllen ICancer Research UKNational Institute for Health Research (NIHR)Wellcome Trust651-661https://www.ebi.ac.uk/biostudies/studies/S-EPMC7616773biostudies-literatureUnknown43(6)<h4>Purpose</h4>Second primary cancer (SPC) risks after breast cancer (BC) in <i>BRCA1/BRCA2</i> pathogenic variant (PV) carriers are uncertain. We estimated relative and absolute risks using a novel linkage of genetic testing data to population-scale National Disease Registration Service and Hospital Episode Statistics electronic health records.<h4>Methods</h4>We followed 25,811 females and 480 males diagnosed with BC and tested for germline <i>BRCA1/BRCA2</i> PVs in NHS Clinical Genetics centers in England between 1995 and 2019 until SPC diagnosis, death, migration, contralateral breast/ovarian surgery plus 1 year, or the 31st of December 2020. We estimated standardized incidence ratios (SIRs) using English population incidences, hazard ratios (HRs) comparing carriers to noncarriers using Cox regression, and Kaplan-Meier 10-year cumulative risks.<h4>Results</h4>There were 1,840 <i>BRCA1</i> and 1,750 <i>BRCA2</i> female PV carriers. Compared with population incidences, <i>BRCA1</i> carriers had elevated contralateral BC (CBC; SIR, 15.6 [95% CI, 11.8 to 20.2]), ovarian (SIR, 44.0 [95% CI, 31.4 to 59.9]), combined nonbreast/ovarian (SIR, 2.18 [95% CI, 1.59 to 2.92]), colorectal (SIR, 4.80 [95% CI, 2.62 to 8.05]), and endometrial (SIR, 2.92 [95% CI, 1.07 to 6.35]) SPC risks. <i>BRCA2</i> carriers had elevated CBC (SIR, 7.70 [95% CI, 5.45 to 10.6]), ovarian (SIR, 16.8 [95% CI, 10.3 to 26.0]), pancreatic (SIR, 5.42 [95% CI, 2.09 to 12.5]), and combined nonbreast/ovarian (SIR, 1.68 [95% CI, 1.24 to 2.23]) SPC risks. Compared with females without <i>BRCA1/BRCA2</i> PVs on testing, <i>BRCA1</i> carriers had elevated CBC (HR, 3.60 [95% CI, 2.65 to 4.90]), ovarian (HR, 33.0 [95% CI, 19.1 to 57.1]), combined nonbreast/ovarian (HR, 1.45 [95% CI, 1.05 to 2.01]), and colorectal (HR, 2.93 [95% CI, 1.53 to 5.62]) SPC risks. <i>BRCA2</i> carriers had elevated CBC (HR, 2.40 [95% CI, 1.70 to 3.40]), ovarian (HR, 12.0 [95% CI, 6.70 to 21.5]), and pancreatic (HR, 3.56 [95% CI, 1.34 to 9.48]) SPC risks. Ten-year cumulative CBC, ovarian, and combined nonbreast/ovarian cancer risks were 16%/6.3%/7.8% (<i>BRCA1</i> carriers), 12%/3.0%/6.2% (<i>BRCA2</i> carriers), and 3.6%/0.4%/4.9% (noncarriers). Male <i>BRCA2</i> carriers had higher CBC (HR, 13.1 [95% CI, 1.19 to 146]) and prostate (HR, 5.61 [95% CI, 1.96 to 16.0]) SPC risks than noncarriers.<h4>Conclusion</h4>Survivors of BC carrying <i>BRCA1</i> and <i>BRCA2</i> PVs are at high SPC risk. They may benefit from enhanced surveillance and risk-reduction measures.Journal of clinical oncology : official journal of the American Society of Clinical OncologySecond Primary Cancer Risks After Breast Cancer in <i>BRCA1</i> and <i>BRCA2</i> Pathogenic Variant Carriers.PMC7616773NIHR203312PPRPGM-Nov20\100002203924/Z/16/ZLoong LTischkowitz MAntoniou ACSantaniello FLavelle KLuchtenborg MGoel SKnott CTorr BVernon SHuntley CHassan HMorris ETurnbull CMcRonald FPethick JBacon AGarrett AAllen IWalburga YJose SEccles DPharoah PRahman TWang YWAllen SHardy SfalseSecond Primary Cancer Risks After Breast Cancer in <i>BRCA1</i> and <i>BRCA2</i> Pathogenic Variant Carriers.<h4>Purpose</h4>Second primary cancer (SPC) risks after breast cancer (BC) in <i>BRCA1/BRCA2</i> pathogenic variant (PV) carriers are uncertain. We estimated relative and absolute risks using a novel linkage of genetic testing data to population-scale National Disease Registration Service and Hospital Episode Statistics electronic health records.<h4>Methods</h4>We followed 25,811 females and 480 males diagnosed with BC and tested for germline <i>BRCA1/BRCA2</i> PVs in NHS Clinical Genetics centers in England between 1995 and 2019 until SPC diagnosis, death, migration, contralateral breast/ovarian surgery plus 1 year, or the 31st of December 2020. We estimated standardized incidence ratios (SIRs) using English population incidences, hazard ratios (HRs) comparing carriers to noncarriers using Cox regression, and Kaplan-Meier 10-year cumulative risks.<h4>Results</h4>There were 1,840 <i>BRCA1</i> and 1,750 <i>BRCA2</i> female PV carriers. Compared with population incidences, <i>BRCA1</i> carriers had elevated contralateral BC (CBC; SIR, 15.6 [95% CI, 11.8 to 20.2]), ovarian (SIR, 44.0 [95% CI, 31.4 to 59.9]), combined nonbreast/ovarian (SIR, 2.18 [95% CI, 1.59 to 2.92]), colorectal (SIR, 4.80 [95% CI, 2.62 to 8.05]), and endometrial (SIR, 2.92 [95% CI, 1.07 to 6.35]) SPC risks. <i>BRCA2</i> carriers had elevated CBC (SIR, 7.70 [95% CI, 5.45 to 10.6]), ovarian (SIR, 16.8 [95% CI, 10.3 to 26.0]), pancreatic (SIR, 5.42 [95% CI, 2.09 to 12.5]), and combined nonbreast/ovarian (SIR, 1.68 [95% CI, 1.24 to 2.23]) SPC risks. Compared with females without <i>BRCA1/BRCA2</i> PVs on testing, <i>BRCA1</i> carriers had elevated CBC (HR, 3.60 [95% CI, 2.65 to 4.90]), ovarian (HR, 33.0 [95% CI, 19.1 to 57.1]), combined nonbreast/ovarian (HR, 1.45 [95% CI, 1.05 to 2.01]), and colorectal (HR, 2.93 [95% CI, 1.53 to 5.62]) SPC risks. <i>BRCA2</i> carriers had elevated CBC (HR, 2.40 [95% CI, 1.70 to 3.40]), ovarian (HR, 12.0 [95% CI, 6.70 to 21.5]), and pancreatic (HR, 3.56 [95% CI, 1.34 to 9.48]) SPC risks. Ten-year cumulative CBC, ovarian, and combined nonbreast/ovarian cancer risks were 16%/6.3%/7.8% (<i>BRCA1</i> carriers), 12%/3.0%/6.2% (<i>BRCA2</i> carriers), and 3.6%/0.4%/4.9% (noncarriers). Male <i>BRCA2</i> carriers had higher CBC (HR, 13.1 [95% CI, 1.19 to 146]) and prostate (HR, 5.61 [95% CI, 1.96 to 16.0]) SPC risks than noncarriers.<h4>Conclusion</h4>Survivors of BC carrying <i>BRCA1</i> and <i>BRCA2</i> PVs are at high SPC risk. They may benefit from enhanced surveillance and risk-reduction measures.2025-01-01T00:00:00Z2025 Feb2025-04-22T16:55:52.422Z2025-04-06T01:58:40.504ZS-EPMC76167733947529510.1200/JCO.24.01146