Table 3.

Sensitivity analysis on gains in life expectancy for BRCA1 and BRCA2 mutation carriers when varying assumption related to breast cancer incidence after the age of 69

Life expectancy ya
BRCA1 mutation carrierAge at carrier status determination and incidence scenarioBRCA2 mutation carrierAge at carrier status determination and incidence scenario
Strategy30 base caseb30 scenario A,c30 scenario B,d30 base caseb30 scenario A,c30 scenario B,d
No S and no PM and no PO41.541.741.448.648.848.5
Gain in life expectancy, y
 Sa2.62.62.61.61.61.6
 PM5.25.15.33.13.03.3
 PO7.47.47.43.03.03.1
 PM and PO10.310.210.44.44.24.5
 S and PO8.88.88.83.73.63.8
Gain in life expectancy when prophylactic surgery is delayed by 5 y
 Delayed PM4.64.54.72.92.73.0
 Delayed PO7.07.07.02.92.83.0
 Delayed PM and PO9.69.49.74.13.94.3
 S and delayed PM4.94.75.03.02.83.1
 S and delayed PO8.68.58.63.63.53.7
 S and delayed PM and PO9.99.710.04.24.14.4
Gain in life expectancy when prophylactic surgery is delayed by 10 y
 Delayed PM3.73.63.82.52.32.7
 Delayed PO5.55.65.52.32.22.3
 Delayed PM and PO8.28.18.33.73.53.8
 S and delayed PM4.44.34.52.82.62.9
 S and delayed PO7.67.67.63.33.23.3
 S and delayed PM and PO9.08.99.14.03.84.3

NOTE: All gains are reported in addition to the base life expectancy (first row of table), in which no intervention is conducted. Assumptions underlying results are: age at genetic testing for BRCA1/2 mutations is at age 30. and the cancer incidence rates beyond age 69 years are: base case, scenario A, and scenario B.

Abbreviations: PM, prophylactic mastectomy; PO, prophylactic oophorectomy; S, screening.

aAll results are for a 1980 birth cohort. b: Base case: cancer risk beyond the age of 69 is interpolated between ages 69 and 85 to match the general population risk at age 85, and kept constant after age 85 (See Supplementary Appendix SI).

cScenario A: cancer risk beyond the age of 69 is similar to that of the general population, based on the SEER registry.

dScenario B: cancer risk beyond the age of 69 is assumed constant for the last year in which BRCA1/2 mutation–associated incidence is estimated.