Avoiding inappropriate surgery for secondary rectal cancer

Secondary rectal carcinoma occurs by invasion of the rectum by local primaries or by metastatic spread from a distant primary. The principle management of primary rectal carcinoma is surgery, but this is not usually the case for secondary carcinoma. This study investigates how these two may be differentiated and inappropriate surgery, in particular inappropriate abdominoperineal excision, can be avoided.

There were six patients with secondary carcinoma of the rectum. The primary tumours were: prostate (three), endometrium (two), breast (one).

All the patients presented with lower gastrointestinal symptoms and four had a palpable mass on rectal examination. The diagnosis was made on histology and immunohistochemistry. Treatment was with endocrine therapy, chemotherapy, radiotherapy, and surgery. Three patients had palliative surgical procedures, and one had a curative anterior resection. The median survival was 7.5 months.

This study has found that the presentation of primary and secondary rectal carcinoma is similar, and the method for distinguishing between the two is histology and immunohistochemistry. Staining for prostate-specific antigen was 100% accurate in the diagnosis of secondary rectal carcinoma arising from a prostate primary. The treatment of secondary rectal carcinoma is with systemic therapy and surgery is usually palliative, and therefore abdominoperineal excision should be avoided.