Table 3

Derivation of age formula for breast cancer moderate risk criteria (>20%) using Claus tables

The sum of the ages in each of the highlighted boxes ranges from 100 to 118 years, thus setting the criterion that increased surveillance is required for individuals with an FDR and SDR whose ages at diagnosis added together are ⩽118 years.
FDR, first degree relative; SDR, second degree relative.
Age of onset of mother (FDR): 20–29 years
Age of onset of maternal aunt (SDR)	20–29	30–39	40–49	50–59	60–69	70–79
Risk by age 79	0.450	0.437	0.417	0.388	0.349	0.305
Age of onset of mother (FDR): 30–39 years
Age of onset of maternal aunt (SDR)	20–29	30–39	40–49	50–59	60–69	70–79
Risk by age 79	0.433	0.414	0.383	0.343	0.296	0.248
Age of onset of mother (FDR): 40–49 years
Age of onset of maternal aunt (SDR)	20–29	30–39	40–49	50–59	60–69	70–79
Risk by age 79	0.407	0.377	0.338	0.289	0.239	0.196
Age of onset of mother (FDR): 50–59 years
Age of onset of maternal aunt (SDR)	20–29	30–39	40–49	50–59	60–69	70–79
Risk by age 79	0.369	0.329	0.281	0.233	0.188	0.154
Age of onset of mother (FDR): 60–69 years
Age of onset of maternal aunt (SDR)	20–29	30–39	40–49	50–59	60–69	70–79
Risk by age 79	0.320	0.274	0.225	0.182	0.148	0.124
Age of onset of mother (FDR): 70–79 years
Age of onset of maternal aunt (SDR)	20–29	30–39	40–49	50–59	60–69	70–79
Risk by age 79	0.264	0.219	0.177	0.143	0.120	0.105