Patients with breast cancer detected between two routine screening exams (interval cancer) have an increased risk of developing other cancers according to a paper published online in Nature Communications this week. They are also more likely to report a family history of multiple cancers. These findings may provide new guidelines for implementing cancer prevention programs.
Interval breast cancers are characterized by larger tumour size and increased metastasis. They are more aggressive and have a worse prognosis than those found during screenings.
Felix Grassmann and colleagues analysed the data collected from two studies in Sweden and one from the US, which included a total of 14,846 patients with breast cancer. Of these 1,772 were interval breast cancer cases. They found that patients with interval breast cancer had an increased likelihood of being previously or later diagnosed with another type of tumour such as lung, colon and skin carcinoma. Patients with interval breast cancer who were also diagnosed with another type of cancer, were three times more likely to report a family history with multiple cancers than non-interval patients, which suggests heritable rare mutations may have a role in these outcomes.
Taking these results into consideration might help to update current cancer prevention programs, for example including additional screenings in specific populations, and increase awareness among interval breast cancer survivors and their relatives the authors suggest future investigations will be necessary to elucidate which specific rare mutations are associated with interval breast cancer and multiple tumours.