Synchronous Breast and Colorectal Malignant Tumors-A Systematic Review

The incidence of breast and colorectal cancers is well established in studies, but the synchronous occurrence of the two types of tumors is a rarity. In general, they are discovered during screening investigations following the diagnosis of an initial tumor.

Our aim is to describe the main diagnostic and therapeutic challenges for synchronous breast and colorectal tumors.

We performed a systematic review of the literature for cases or case series, using established keywords (synchronous breast and colon tumor and synonyms) for the period of 1970-2023. Five reviewers independently screened the literature, extracted data, and assessed the quality of the included studies. The results were processed according to the PRISMA 2020 guidelines.

A total of 15 cases were included in the study, including 2 males (age 50 and 57) and 13 females (median age 60, with range from 40 to 79). In a vast majority of the cases, the diagnosis of synchronous tumor was prompted by the first tumor's workup. The first diagnosed tumor was colorectal in nine cases and a breast tumor in six cases. The most common histopathological type of breast tumor was invasive ductal carcinoma, and the colon tumors were exclusively adenocarcinomas. All cases had a surgical indication for both breast and colorectal tumor, except one case, in which the breast tumor had multiple metastasis. In four cases, the surgery was performed concomitantly (colectomy and mastectomy). In three cases, surgery was initially carried out for the breast tumor, followed by colon surgery. Oncological treatment was indicated depending on the tumor stage.

For the treatment of synchronous tumors, the Tumor Board (T.B) decision is mandatory and must be personalized for each patient. Developing new methods of treatment and investigation may play an important role in the future for understanding synchronous tumor development, incidence, and outcome.