Aims: This study seeks to assess the impact of breast cancer on survivors' annual income at 1 to 13 years of follow-up.
Methods: A Norwegian registry-based dataset with a 13-year follow-up period was used. The dataset contained case-control pairs, where each pair consisted of one breast cancer case and a cancer-free control, matched for age, marital status, and municipality of residence. A mixed linear model was used to analyse the average income development for cases and controls adjusting for available demographic variables not used in the matching procedure, such as education level, immigration history, and number of children. Individual income was only considered relevant for cancer survivors, thus case-control pairs were censored upon death. Income development by stage of tumour at time of diagnosis was also assessed.
Results: The income of breast cancer survivors had reduced immediately following diagnosis. At 1 year after diagnosis, income development between cases and controls became significantly different (p = 0.006). Differences increased slightly but remained significant throughout the follow-up period. At 13 years after diagnosis, the estimated cumulative income loss for survivors was 39.403 € (p < 0.001). The income development of stage I breast cancer patients was similar to their controls. For higher stage breast cancer patients, the income differences were more pronounced but not always statistically significant.
Conclusions: Breast cancer has a significant negative effect on the individual incomes of survivors, even at 13 years after diagnosis. Effects increased for individuals with more advanced cancer stages.
Implications for cancer survivors: In Norway, breast cancer survivors experience lower income than their cancer-free controls. This may indicate a need for financial compensations in order to maintain the standard of living for this group of patients.