Background
There is uncertainty about the benefits of using genome-wide
sequencing to implement personalized preventive strategies at the population
level, with some projections suggesting little benefit. We used data for all
currently known breast cancer susceptibility variants to assess the benefits
and harms of targeting preventive efforts to a population subgroup at
highest genomic risk of breast cancer.
Methods
We used the allele frequencies and effect sizes of 86 known breast
cancer variants to estimate the population distribution of breast cancer
risks and evaluate the strategy of targeting preventive efforts to those at
highest risk. We compared the efficacy of this strategy to that of a
“best-case” strategy based on a risk distribution estimated
from breast cancer concordance in monozygous twins, and to strategies based
on previously estimated risk distributions.
Results
Targeting those in the top 25% of the risk distribution would
include approximately half of all future breast cancer cases, compared to
70% captured by the best-case strategy and 35% based on
previously known variants. In addition, current evidence suggests that
reducing exposure to modifiable nongenetic risk factors will have greatest
benefit for those at highest genetic risk.
Conclusions
These estimates suggest that personalized breast cancer preventive
strategies based on genome sequencing will bring greater gains in disease
prevention than previously projected. Moreover these gains will increase
with increased understanding of the genetic etiology of breast cancer.
Impact
These results support the feasibility of using genome-wide sequencing
to target the women who would benefit from mammography screening.