The diagnosis of breast cancer in a 31-year-old woman was delayed, apparently because she did not comply with advice to come for a follow-up appointment after an initial diagnosis of adenofibroma. For this she held her general practitioner (GP) responsible. In the ensuing legal battle the court expert testified that the GP had complied with the appropriate practice guideline. Of particular importance was the fact that breast cancer at her age is very rare. In my view, however, it was erroneous to estimate the probability of cancer based solely on her age, since the a priori probability of cancer in women with a solid breast mass visiting their GP is approximately 10%. Exclusion of malignancy requires the most sensitive diagnostic strategy, unfortunately not applied in this case. The Dutch College of General Practitioners’ practice guidelines on diagnostic strategies in breast cancer should be based on a more accurate estimate of breast cancer probability in specified groups and the requirement that the test strategy sufficiently rules out cancer.
Conflict of interest: none declared. Financial support: none declared.