Introduction In the Netherlands, breast cancer patients are treated according to national guidelines. Despite comprising a large proportion, elderly breast cancer patients are underrepresented in clinical trials. Therefore it is questionable whether guideline recommendations can be extrapolated from a young to a heterogeneous elderly population. Aim of this study was to assess age specific guideline adherence.

Methods Data were extracted from the Dutch Cancer Registration. Overall, 83 982 patients without distant metastases, diagnosed between 2002 and 2008 were included. Adherence was assessed for breast surgery (BS), type of surgery (TS), axillary surgery (AS) and radiotherapy (RT). Analyses were stratified by age (<65, 65–74 and ≥75 years).

Results Adherence decreased with increasing age (BS <65, 99%; 65–74, 98%; ≥75, 75%; p<0.001. TS 69%; 66%; 42% respectively, p<0.001. AS 96%; 94%; 68% respectively, p<0.001. RT 91%; 93%; 83% respectively, p<0.001). BS and AS non adherence were explained by under treatment. For TS and RT, young patients were non adherent because of over- and under treatment. In the elderly, under treatment was the main reason for non adherence (under treatment TS 84%; 91%; 97% respectively, p<0.001. RT 34%; 50%; 80% respectively, p<0.001). Over time adherence to breast surgery declined for elderly patients (p<0.001). For other local therapies, the gap between young and elderly patients remained similar.

Conclusion These results emphasise the different approach and treatment of elderly breast cancer patients. Further age specific studies in breast cancer patients are necessary to investigate whether adherence to current guidelines results in optimal outcomes for elderly patients.