Breast Cancer: Increased Risk after BRCA-positive Ovarian Cancer?

About 1 in 300 to 1 in 800 people in the general population carries a BRCA1 or BRCA2 mutation. This increases the risk of breast cancer in affected women by 45-85 percent by the age of 75. But what is the risk of breast cancer after BRCA-positive ovarian cancer?

Does BRCA-positive ovarian cancer justify breast cancer screenings?

Breast cancer rate comparable to the general population

A total of 284 women with BRCA-associated EOC were included in the study. Fifty-two of these women opted for a risk-reducing mastectomy due to their BRCA status and were therefore excluded from further evaluation.

The remaining 232 women were followed up for a mean period of 5.6 years after treatment for their ovarian carcinoma. After the EOC, 33 (14%) women were diagnosed with breast cancer in this period: These included 27 (11%) new cases and 6 (3%) tumour recurrences. 

How was this breast cancer diagnosed?

Twelve (36%) women received their diagnosis after mammography screening, 4 (12%) after MRI screening and 9 (27%) during an examination after palpable lump findings. In 29 of the 33 breast cancer diagnoses (87%), the breast cancer was in an early stage (0-II) of the disease.

The median duration between BRCA-associated ovarian cancer and subsequent breast cancer was 80 months for new diagnoses and 63 months for recurrent breast cancer. One woman died of breast cancer and 12 women died of ovarian cancer.

Increased breast cancer screenings necessary for BRCA-positive status? 

Most breast carcinomas following BRCA-associated EOC were at an early stage and did not entail increased mortality. Furthermore, the observed breast cancer rate did not differ from that of the general population. 

The median time to diagnosis of breast cancer after surviving EOC was also 6.6 years. In conclusion, the researchers do not deduce any justification for increased breast cancer screenings in the first years after EOC diagnosis.

Source:
Nanez A et al., Breast cancer risk in BRCA mutation carriers after diagnosis of epithelial ovarian cancer is lower than in carriers without ovarian cancer. Gynecologic Oncology Reports 2022; 39: 100899