Squamous rectal carcinoma: a rare malignancy, literature review and management recommendations

Squamous cell carcinoma of the rectum is a rare malignancy (0.3% of all rectal cancers), with no known risk factor. These tumours are assessed as rectal cancer using immunohistochemical and radiological tests, and certain criteria (localisation, relationship with neighbouring structures) have to be fulfilled to make the diagnosis. Some clinicians used to stage them with the anal cancer TNM (tumour-node-metastasis), whereas others used the rectal cancer TNM. When localised, the tendency nowadays is to treat those tumours like squamous anal cancers with definitive chemoradiotherapy (5-fluorouracil and mitomycin) and to skip surgery. For metastatic disease there is no clearly validated regimen and treatment should be based on recommendations of squamous anal cancers because of their common histology. Concerning follow-up after a curative approach, techniques should follow those for anal cancer as well, evaluating a delayed response.