{
  "abstract": "Importance: Young BRCA carriers may undergo breast-conserving surgery (BCS) or mastectomy with or without contralateral risk-reducing mastectomy at the time of an index breast cancer diagnosis. A variety of factors may influence surgical decision-making. Objective: To explore surgical patterns of care and factors associated with uptake of bilateral mastectomy among affected BRCA1 or BRCA2 (BRCA1/2) carriers diagnosed with early-onset breast cancer. Design, Setting, and Participants: The BRCA BCY Collaboration is an international, hospital-based retrospective cohort study conducted at 109 centers across 5 continents. Women aged 40 years or younger with germline pathogenic or likely pathogenic variants in BRCA1/2 who were diagnosed between January 1, 2000, and December 31, 2020, with invasive stage I to III breast cancer were included. Data were collected between January 2022 and June 2024, and analyses were performed between May 21 and 28, 2025. Main Outcome and Measures: The main outcome was the evaluation of surgical management as primary treatment for a first diagnosis of invasive breast cancer, defined as BCS, unilateral mastectomy, or bilateral mastectomy. Results: Of 5660 eligible BRCA1/2 carriers, 4715 women (median [IQR] age, 35 [31-38] years) had unilateral stage I to III breast cancer with surgical treatment details available. In the cohort, 1805 patients (38.3%) underwent BCS, 1752 (37.2%) underwent unilateral mastectomy, and 1158 (24.6%) underwent bilateral mastectomy. The proportion of BRCA1/2 carriers undergoing BCS decreased over the study period (55.7% [49 of 88] in 2000 vs 27.0% [82 of 304] in 2020), whereas the use of bilateral mastectomy significantly increased (8.0% [7 of 88] in 2000 vs 44.4% [135 of 304] in 2020). Bilateral mastectomy was more common in women who had genetic testing performed before (248 of 435 [57.0%]) or within 6 months (729 of 1892 [38.5%]) of a breast cancer diagnosis compared with those tested after diagnosis (111 of 2167 [5.1%]). On multivariable analysis, compared with those tested after diagnosis, earlier genetic testing was the factor most strongly associated with bilateral mastectomy receipt (testing prior to diagnosis: adjusted odds ratio, 20.72 [95% CI, 15.27-28.13]; testing at diagnosis: adjusted odds ratio, 6.83 [95% CI, 5.39-8.66]). In subgroup analyses, including 2327 patients who had genetic testing performed before or within 6 months of diagnosis, 977 (42.0%) underwent bilateral mastectomy, with the lowest rates reported in Asia and Africa (130 of 499 [26.1%]) and the highest rates reported in North America (233 of 351 [66.4%]). Conclusions and Relevance: The findings of this cohort study of young BRCA1/2 carriers suggest that geographic region and timing of genetic testing were the factors most strongly associated with surgical management.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 40,
  "authors": [
    {
      "name": "Stephanie Wong"
    },
    {
      "name": "Eva Blondeaux"
    },
    {
      "name": "Virginia Delucchi"
    },
    {
      "name": "Florence Coussy"
    },
    {
      "name": "Rinat Bernstein Molho"
    },
    {
      "name": "Sabine Linn"
    },
    {
      "name": "Antonio Di Meglio"
    },
    {
      "name": "Ava Kwong"
    },
    {
      "name": "Katarzyna Pogoda"
    },
    {
      "name": "Elisa Agostinetto"
    },
    {
      "name": "Ines Nevelsteen"
    },
    {
      "name": "Judith Balmaña"
    },
    {
      "name": "Halle Moore"
    },
    {
      "name": "Angela Toss"
    },
    {
      "name": "Alberta Ferrari"
    },
    {
      "name": "Christine Rousset-Jablonski"
    },
    {
      "name": "Tiphaine Renaud"
    },
    {
      "name": "Kelly-Anne Phillips"
    },
    {
      "name": "Fedro Peccatori"
    },
    {
      "name": "Maria Agustina Ipina"
    },
    {
      "name": "Shani Paluch-Shimon"
    },
    {
      "name": "Jai Min Ryu"
    },
    {
      "name": "Wanda Cui"
    },
    {
      "name": "Minna Lee"
    },
    {
      "name": "Robert Fruscio"
    },
    {
      "name": "Mariya Rozenblit"
    },
    {
      "name": "Claudio Vernieri"
    },
    {
      "name": "Alexios Matikas"
    },
    {
      "name": "Maria Vittoria Dieci"
    },
    {
      "name": "Fergus Couch"
    },
    {
      "name": "Laura de Marchis"
    },
    {
      "name": "Shelley Hwang"
    },
    {
      "name": "Dione Aguilar y Mendez"
    },
    {
      "name": "Deniz Can Guven"
    },
    {
      "name": "Monique Swain"
    },
    {
      "name": "Caterina Gianni"
    },
    {
      "name": "Stefano Spinaci"
    },
    {
      "name": "Giacomo Montagna"
    },
    {
      "name": "Matteo Lambertini"
    },
    {
      "name": "Hee Jeong Kim"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9g7w9418073tv.bib",
  "cited_by": 0,
  "doi": "10.1001/jamanetworkopen.2026.30856",
  "fulltext_url": null,
  "id": "9g7w9418073tv",
  "issns": [
    "2574-3805"
  ],
  "landing_url": "https://hal.science/hal-05749317v1",
  "language": "en",
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.sdv"
    ],
    [
      "hal",
      "1.sdv.spee"
    ],
    [
      "openalex",
      "1311|BRCA gene mutations in cancer"
    ]
  ],
  "openalex": "W7204228586",
  "pdf_url": null,
  "pmcid": null,
  "pmid": "42646839",
  "published": "2026-08-26",
  "publisher": "American Medical Association",
  "ris": "https://research.draconitic.com/paper/9g7w9418073tv.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:34Z",
      "native_id": "hal-05749317",
      "source": "hal",
      "url": "https://hal.science/hal-05749317v1"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "hal:0.sdv",
      "subfield": "general"
    },
    {
      "field": "medicine",
      "origin": "hal:1.sdv.spee",
      "subfield": "epidemiology-public-health"
    }
  ],
  "title": "Surgical Management of Early-Onset Breast Cancer Among Young BRCA1 and BRCA2 Carriers",
  "title_text": "Surgical Management of Early-Onset Breast Cancer Among Young BRCA1 and BRCA2 Carriers",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:17:34Z",
  "url": "https://research.draconitic.com/paper/9g7w9418073tv",
  "venue": "JAMA Network Open",
  "versions": []
}