Scripties UMCG - Rijksuniversiteit Groningen
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The effect of risk-reducing salpingo-oophorectomy on the breast cancer risk in BRCA1 and BRCA2 mutation carriers : Risks to develop breast cancer and ovarian cancer by age 70 and 5-years cumulative risk to develop contralateral breastcancer for the genera

(2017) Stuursma, A. (Anniek)

Background: Women with a BRCA1/2 mutation have an increased risk to develop breast and ovarian
cancer, and also to develop contralateral breast cancer. To reduce the risk of ovarian cancer, women
are advised to undergo risk-reducing salpingo-oophorectomy (RRSO) at premenopausal age (before
the incidence strongly rises), which is currently the only effective option. According to some studies,
RRSO at premenopausal age may also reduce the breast cancer risk. However, other studies could not
reproduce these results and this is now a subject of discussion. This is clinically relevant, because
prevention advices for breast cancer are based on factual cancer risks. The aim of this study was to
investigate the primary and contralateral breast cancer risk after RRSO in BRCA1/2 mutation carriers
who were counselled or treated in the UMCG, in order to improve pre-surgery counselling.
Methods: In this prospective cohort study, we followed 1142 proven BRCA1/2 mutation
carriers. To investigate the risk of primary and contralateral breast cancer after RRSO, we performed
Cox-regression analyses with RRSO as a time-dependent variable.
Results: During 4085 person-years of follow-up, 121 primary breast cancers developed, of
which 21 developed after RRSO and 2 developed in the latency period of 6 months after RRSO.
During 1951 person-years of follow-up 22 breast cancers developed, of which 5 developed after
RRSO and 7 developed in the latency period. The Cox-regression analyses did not gain any
statistically significant increased or decreased hazard ratios for the primary and contralateral breast
cancer risk after RRSO (HRBC =1.46, 95%CI =0.84-2.55, HRCBC =1.025, 95%CI = 0.99-1.06).
Interpretation: This study shows that RRSO at premenopausal age may not have an effect on
incidence of breast cancer or contralateral breast cancer. More follow-up years and larger numbers of
carriers are necessary to draw valid conclusions. The most important goal of RRSO remains to
decrease ovarian cancer risk.

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