BRCA2 patients develop breast cancer at the same stage as BRCA1 however develop ovarian cancer at a later stage


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Gareth Irwin1,Gwyneth Hinds1,Lesley McFaul1,Patrick Morrison1,Ian Harley1,Stuart McIntosh2
1Belfast City Hospital,2Belfast City Hospital/Queen's University Belfast

Abstract

Background

BRCA testing was introduced in Northern Ireland in 1996 and since then people have had diagnostic and predictive testing. Patients identified with a BRCA mutation are offered risk-reducing surgery to the breast and ovaries. Information on all patients identified with a BRCA mutation was collected to identify rates of cancer.

Method

Patients were identified on the Northern Ireland BRCA database. Treatment regimes, surgical outcomes and tumour biology were obtained from COIS, Pathology database and the patients’ notes.

Results

From 822 patients, 328(41%), with full follow-up, were found to have a BRCA1 mutation with 476 having a BRCA2 mutation. 42% of the BRCA1 patients had a breast cancer diagnosis compared to 35% of the BRCA2 patients. Ovarian cancer was diagnosed in 15% of BRCA1s compared to 9% of BRCA2s. There were no diagnoses of breast cancer in patients aged less than 25, however there were 11 cases of breast cancer diagnosed before the age of 30, the onset of breast screening. There were no BRCA1 diagnoses of ovarian cancer in the under 35s, or in the under 40s with BRCA2, with only 1 case under 45.

Conclusion

BRCA1 and 2 breast cancer occurs with a similar age distribution with a significant number outwith current breast cancer screening age groups. Ovarian cancer occurs later in BRCA2, suggesting risk-reducing surgery could be offered later in this age group compared to BRCA1 patients.