Prevalence, risk factors, and prognosis of peritoneal metastasis from breast cancer.

Peritoneal metastasis from breast cancer is a serious and deadly condition only limited considered in the literature. Our aim was to study prevalence, risk factors, and prognosis of breast cancer peritoneal metastasis. We retrospectively analyzed 3096 women with a diagnosis of invasive breast cancer. We took into consideration presence and localization of breast cancer distant metastasis as well as the possible risk factors and survival from the diagnosis of the breast cancer metastasis. The prevalence of breast cancer peritoneal metastases was 0.7 % (22/3096), representing the 7.6 % (22/289) of women affected by distant metastases. Moreover, independent risk factors for breast cancer peritoneal metastases resulted high grading, lobular invasive histology, and advanced T and N stage at diagnosis. Overall survival after metastasis diagnosis was shorter in women affected by peritoneal metastases or brain metastases in comparison to other metastatic women. Breast cancer peritoneal metastases were uncommon but not rare events with a poor prognosis after standard treatments.