by D.Gareth Evans, Ashu Gandhi, Julie Wisely, Tara Clancy,
Emma R. Woodward, James Harvey, Lyndsey Highton, John Murphy, Lester Barr,
Sacha J. Howell, Fiona Lalloo, Elaine F. Harkness, Anthony Howell
The Breast: August 26, 2021
Highlights
•BRRM continues even 20 years post original breast cancer
risk assessment.
•Potential triggers include death of mother/sister, children
and a breast biopsy.
•Uptake is clearly informed by lifetime risk of BC and
higher in younger the women.
Background
Bilateral-Risk-Reducing-Mastectomy-(BRRM) is well described
in BRCA1/2 pathogenic variant carriers. However, little is known
about the relative uptake, time trends or factors influencing uptake in those
at increased breast cancer risk not known to be carriers. The aim of this study
is to assess these factors in both groups.
Methods
BRRM uptake was assessed from entry to the Manchester Family
History Clinic or from date of personal BRCA1/2 test. Follow up was
censored at BRRM, breast cancer diagnosis, death or January 01, 2020.
Cumulative incidence and cause specific and competing risk regression analyses
were used to assess the significance of factors associated with BRRM.
Results
Of 7195 women at ≥25% lifetime breast cancer risk followed
for up to 32 years, 451 (6.2%) underwent pre-symptomatic BRRM. Of those
eligible in different risk groups the 20-year uptake of BRRM was
47.7%-(95%CI = 42.4–53.2%) in 479 BRCA1/2 carriers; 9.0%
(95%CI = 7.26–11.24%) in 1261 women at ≥40% lifetime risk (non-BRCA),
4.8%-(95%CI = 3.98–5.73%) in 3561 women at 30–39% risk and
2.9%-(95%CI = 2.09–4.09%) in 1783 women at 25–29% lifetime risk. In
cause-specific Cox regression analysis death of a sister with breast
cancer<50 (OR = 2.4; 95%CI = 1.7–3.4), mother<60
(OR = 1.9; 95%CI = 1.5–2.3), having children
(OR = 1.4; 95%CI = 1.1–1.8), breast biopsy (OR = 1.4;
95%CI = 1.0–1.8) were all independently associated with BRRM uptake,
while being older at assessment was less likely to be associated with BRRM
(>50; OR = 0.26,95%CI = 0.17–0.41). Uptake continued to
rise to 20 years from initial risk assessment.
Conclusion
We have identified several additional factors that correlate
with BRRM uptake and demonstrate continued increases over time. These factors
will help to tailor counselling and support for women.
