BRCA associated breast cancer treatment strategies and outcomes of a Brazilian cancer center

Keywords

BRCA1 - BRCA 2 - breast cancer - hereditary breast and ovarian cancer syn - hereditary cancer syndrome

Introduction: Approximately 10% of breast cancers have a hereditary component, mostly associated with pathogenic variants (PVs) in the BRCA1/2 genes. They typically exhibit genomic instability, but aside from the prioritization of PARP inhibitors and platinum-based therapies, they are treated based on studies of sporadic tumors. Our objective is to describe the tumor characteristics, treatment patterns, and response in patients with BRCA1/2 PVs.

Methods: A retrospective observational study was conducted, including patients with breast cancer who carried BRCA1/2 PVs, treated between January 2004 and August 2024 at A.C. Camargo Cancer Center (Brazil).

Results: All patients (n = 145) were female, with 88 having BRCA1 mutations, 55 having BRCA2 mutations, and 2 patients with mutations in both genes. Mean age: 42 years (±8.67). Ethnicity: White (79%), Brown (11%), Asian (4%), Black (3%), and 3% not reported (NR). Family history of cancer: 54%. 14 patients had synchronous tumors: ovaries n = 11; pancreas n = 1; stomach n = 1. Regarding breast cancer, the predominant histological subtype was NST 88%; CLI 4%; Metaplastic 2%; others: 6%. The majority were high grade (GIII 62%, GII 33%, GI 3%, 2% NR), of the triple-negative subtype 51%; Luminal B: 27%; Luminal B HER-2 low: 8%; Luminal A: 7%; Luminal B HER-2+ 4%; HER-2+: 2%; Basal-like 1%; with up to 20% lymphocytic infiltrate in the tumor (TIL up to 20% n = 77; 21-40% n = 42; >40% n = 9) and diagnosed at early stages EC: (I) n = 75; (II) n = 41; (III) n = 25; (IV) n = 4. 82 patients underwent neoadjuvant chemo with ± immunotherapy ± anti-HER2 therapy. Complete response: 34.6%. Adjuvant RT: 86.9%. 82 patients (55%) received adjuvant systemic therapy – AC-T (28%); iPARP (13%); TC (8%); Capecitabine (7%); others: 44%. Adjuvant HT: 6 years (±2.66). Median follow-up of 60 months: 7.8% local recurrence and 20% distant recurrence. Metastasis sites: lung (32%); bone (20%); liver (16%); lymph node (16%); others (16%). 1st line: exclusive chemo (23%); chemo ± targeted therapy or immunotherapy (43%); iPARP (16%). Time to disease progression: 61 months (±39.5). Five-year median survival: 93.1%. Initial surgery: 20% bilateral mastectomy, 50% unilateral, and 30% segmental resection. 129 (89%) patients had prophylactic BSO.

Conclusion: We observed a predominance of women in their fourth decade of life, white, with early-stage triple-negative NST, most of whom underwent risk-reducing surgery. 93.1% of patients were alive after 5 years of follow-up.

Corresponding author: Andre Luiz Cicilini (e-mail: [e-mail]).

 

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No conflict of interest has been declared by the author(s).

Publication History

Article published online:
06 May 2025