Breast cancer risk based on adapted IBIS prediction model in Slovenian women aged 40-49 years – could it be better?

Abstract

Objective: To assess the proportion of women that would be classified as at above-average risk of breast cancer (BC) based on the 10 year-risk prediction of the S-IBIS program in two presumably above-average BC risk populations in age group 40-49 years: (i) women referred for any reason to diagnostic breast centres and (ii) women who were diagnosed with BC aged 40-49y.

Background: BC is the commonest female cancer in Slovenia, with an incidence rate below European average. The Tyrer-Cuzick BC risk assessment algorithm was recently adapted to Slovenian BC incidence rate (S-IBIS). In Slovenia a tailored mammographic screening for women at above average risk in age group 40-49y is considered in the future. S-IBIS is a possible tool to select population at above-average risk of BC for tailored screening.

Methods:  In 357 healthy women aged 40-49y referred for any reason to diagnostic breast centres and in 367 female BC patients aged 40-49y at time of diagnosis 10-years BC risk was calculated using the S-IBIS software. The proportion of women classified as above-average risk of BC was calculated for each subgroup of the study population.

Results: 48,7% of women in the Breast centre group and 39,2% of patients in the BC group had above-average 10-year BC risk. Positive family history of BC was more prevalent in the Breast centre group (p<0,05).

Conclusion: Inclusion of additional risk factors into the S-IBIS is warranted in the populations with BC incidence below European average to reliably stratify women into BC risk groups.