Clinical Features of Breast Cancer in Young BRCA Carriers: Important Differences

The genetic basis of breast cancer has long been studied. Its clinical course is particularly important in young women carrying BRCA1 and BRCA2 variants that are inherited and pathogenic (harmful mutations) . In a new study published on 24 February 2025 in Journal of Clinical Oncology, Dr. Matteo Lambertini and colleagues compared clinical features in young women with BRCA1 and BRCA2 mutations and investigated the effect of knowing BRCA status before diagnosis on outcomes .

Study Details

The research was conducted at 78 centers worldwide and included data from women diagnosed with stage I-III breast cancer at age 40 or younger between 2000 and 2020 , totaling 4752 patients . Participants carried BRCA1 mutations (3069 people) or BRCA2 mutations (1683 people) .

Main Findings

• Hormone receptor-negative disease and tumor grade: Compared with BRCA2 carriers, BRCA1 carriers more often had hormone receptor-negative tumors (74.4% vs 15.5%) and higher-grade tumors (77.5% vs 49.1%).

• Second primary breast cancer and other primary cancers: During a median follow-up of 7.8 years, BRCA1 carriers had more second primary breast cancers (2.12 vs 1.42 events/100 person-years) and other primary cancers (0.70 vs 0.45 events/100 person-years). Distant metastases, however, were more common among BRCA2 carriers (1.51 vs 2.06 events/100 person-years).

• Disease-free survival: Eight-year disease-free survival was 63,8% in BRCA1 carriers and 66.2% in BRCA2 carriers.

• Prediagnostic BRCA Testing and Clinical Outcomes: Patients tested before breast cancer diagnosis (at least 2 months beforehand, 411 people), compared with those tested around diagnosis (from 2 months before through 6 months after diagnosis, 1671 people), had smaller tumors (T1 tumors: 61.3% vs 32.4%), less lymph node involvement (N0: 65.9% vs 50.8%), less chemotherapy (84.4% vs 92.9%), and lower rates of axillary dissection (37.5% vs 47.4%).

The image above compares survival rates in patients tested for inherited BRCA mutations before or around diagnosis . It includes three graphs:

1. Graph A (Disease-Free Survival):

   • Patients tested before diagnosis (green line) had longer disease-free survival than those tested around diagnosis (orange line).
   • In patients tested around diagnosis, recurrence risk was higher.

2. Graph B (Breast Cancer-Specific Survival):

   • Breast cancer mortality rates were compared.
   • Prediagnostic testing showed a survival advantage, although the difference was not very pronounced.

3. Graph C (Overall Survival):

   • Overall survival rates were examined.
   • Patients tested before diagnosis had a modest long-term survival advantage .

These findings suggest that early genetic testing allows cancer to be diagnosed at an earlier stage and may be associated with better long-term outcomes .

• Effect of Genetic Testing on Survival: Patients tested for BRCA before diagnosis had better overall survival than those tested around diagnosis (HR = 0.61; 95% CI = 0.40–0.92). After adjustment for factors such as tumor stage, however, the difference was no longer statistically significant (HR = 0.74; 95% CI = 0.47–1.15).

Conclusion and Commentary

This global study shows different clinical behavior in young BRCA1 and BRCA2 carriers. Identifying a BRCA mutation before illness was associated with earlier-stage diagnosis, lower treatment burden, and better overall survival in unadjusted analyses.

These findings highlight the importance of early genetic testing for early cancer detection and may contribute to individualized screening strategies .