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

Abstract

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 (tumourenodeemetastasis), 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.

Construction and validation of a prognostic nomogram for anal squamous cell carcinoma

“…Diao et al 50 enrolled 806 RSCC patients and constructed a nomogram to predict 3‐ and 5‐years OS. However, compared with our study, different prognostic factors in demographic characteristics, AJCC stage and treatment options, were identified, which may be caused by the differences in pathogenesis, 51 staging, 52 , 53 and treatment options 49 , 54 between ASCC and RSCC. Due to the rarity of RSCC, much is unknown about this cancer, such as the role of HPV and HIV in RSCC, 55 , 56 the molecular profile or the most effective treatments.…”

“…Nowadays, the trend is to treat rectal squamous cell carcinoma (RSCC) by analogy to ASCC. 49 Because of the same histotype and close localization, we wonder if there are differences in prognostic factors between ASCC and RSCC. Diao et al 50 enrolled 806 RSCC patients and constructed a nomogram to predict 3‐ and 5‐years OS.…”

Synchronous squamous cell carcinoma of rectum and anal canal- a rare entity

“…Squamous cell carcinoma is usually seen in areas with native squamous epithelium like esophagus or anal canal and is uncommon in other parts of gastrointestinal tract. Primary rectal SCC was rst reported by Raiford in 1933 and accounts for only 0.3 % of all rectal malignancies [3]. It is a rare disease with an incidence of 1.9-3.5 cases/million population [4].…”

“…On colonoscopy, both rectal and anal SCC present as a polyp, ulcerative lesion or a nodular stricture with thickening. Diagnosis is usually by histopathological examination of colonoscopic/proctoscopic biopsy [3]. In order to diagnose primary rectal SCC Williams et al [10] proposed ful llment of three criteria which are:…”

“…Local failures in de nitive CRT are treated by salvage surgery. Hence presently most authors recommend a de nitive CRT as treatment of choice for non-metastatic rectal SCC, with surgery reserved for emergencies like obstruction, perforation, bleeding and for treatment failures [1,3,12,13]. Our patient's diagnosis of SCC was established during intra-operative frozen biopsy and post-operative de nitive histopathology; he was also having impending colonic obstruction -so we managed him with abdomino-perineal resection.…”