objective of this study was to assess the incidence of primary breast
cancer (PBC) and contralateral breast cancer (CBC) in patients who had BRCA1/BRCA2-associated epithelial ovarian cancer (OC).
From the database of the Rotterdam Family Cancer Clinic, patients who had BRCA-associated
OC without a history of unilateral breast cancer (BC) (at risk of PBC; n
= 79) or with a history of unilateral BC (at risk of CBC; n = 37) were
selected. The control groups consisted of unaffected BRCA
mutation carriers (n = 351) or mutation carriers who had a previous
unilateral BC (n = 294), respectively. The risks of PBC and CBC were
calculated using the Kaplan-Meier survival method with death considered
as a competing risk event.
Women with BRCA-associated
OC had lower 2-year, 5-year, and 10-year risks of PBC (3%, 6%, and 11%,
respectively) compared with unaffected mutation carriers (6%, 16%, and
28%, respectively; P = .03), although they had a considerably
higher mortality rate at similar time points (13%, 33%, and 61%,
respectively, vs 1%, 2%, and 2%, respectively; P < .001). In BRCA
mutation carriers with a previous unilateral BC, the 2-year, 5-year,
and 10-year risks of CBC were nonsignificantly lower in patients with OC
than in those without OC (0%, 7%, and 7%, respectively, vs 6%, 16%, and
34%, respectively; P = .06), whereas the mortality rate was
higher in patients with OC (19%, 34%, and 55%, respectively, vs 4%, 11%,
and 21%, respectively; P < .001).