Breast cancer screening in patients with cancers other than breast.

Background: Screening mammography can detect early breast cancers and reduce subsequent cancer mortality. However, there is a lack of consensus as to when to discontinue screening. The absence of clear-cut guidelines on when not to screen means that many patients with advanced malignancies continue screening despite unclear benefit.

Methods: We performed a retrospective cohort study of female patients diagnosed with a non-breast malignancy to explore the incidence and effects of screening mammography. Female patients diagnosed with a non-breast malignancy stage II or higher between 2007 and 2012 were identified through the Vermont Cancer Registry and cross-referenced with mammography screening logs from January 1, 2007 to September 30, 2014. Additional data were collected through chart review, in May 2016.

Results: Twenty-six percent of women (398/1501) with a stage II or greater cancer (other than breast) diagnosed between 2007 and 2012 had a screening mammogram within the first 5 years of their diagnosis. Of these 398 women, 193 (48.5%) were alive without cancer, 132 (33.2%) had died, and 73 (18.3%) were alive with cancer at the time of chart review. Of those who died, 84 (63.6%) had a stage III or IV cancer. Eighteen (4.5%) had a breast biopsy following a screening mammogram suspicious for cancer, resulting in 13 (3.3%) benign diagnoses and 5 (1.3%) breast cancer diagnoses. No patient died of breast cancer.

Conclusions: Except for highly curable cancers, female patients diagnosed with an advanced non-breast malignancy experienced mortality that outweighs a breast cancer mortality benefit from screening mammography as estimated from prior studies.