P0198 - A Rare Case of Rectal Squamous Cell Carcinoma Treated With Nigro Protocol

Hunza Chaudhry, MD¹, Sunny Sandhu, MD², Sharon Zhang, MD, PhD³, Devang N. Prajapati, MD, FRCPC^4
1University of California San Francisco Fresno, Fresno, CA; ²University of California San Francisco Fresno, Clovis, CA; ³Community Medical Centers, Fresno, CA; ⁴VA Central California Health Care System; University of California, San Francisco - Fresno, Fresno, CA

Introduction: Squamous cell carcinoma (SCC) of the rectum is an extremely rare malignancy, and the optimal treatment strategy remains unknown. Cases are limited in the literature, and although historically treated with surgical resection, more recent cases have suggested success with chemotherapy. Although Nigro protocol was intially developed for anal SCC, we present a case of rectal SCC successfully treated with the Nigro protocol. Our case supports the use of chemoradiotherapy as initial treatment for rectal SCC over surgery.

Case Description/Methods: A 74-year-old man presented with new-onset microscopic hematuria. As part of workup, he underwent a CT abdomen/pelvis which showed an incidental finding of a 4.8 cm mass arising from the right mid-rectal wall (Figure 1a). He was asymptomatic, and colonoscopy 2 years prior was unremarkable. To evaluate, a colonoscopy was performed which revealed erythematous nodular friable mucosa located in the proximal rectum, 13 cm from the anal verge, with normal intervening mucosa between the anal canal and the lesion (Figure 1c). Biopsies revealed SCC (Figure 1d). PET CT was consistent with primary rectal malignancy with no distant metastases, T3N2aMO Stage IIIb. After multidisciplinary discussion, the patient was treated with Nigro protocol chemoradiotherapy given the relatively distal location of the mass rather than primary surgical resection. Follow-up imaging 3 months later showed a marked decrease in tumor size to a residual soft tissue prominence (Figure 1b).

Discussion: Rectal SCC is rare, with an incidence of 0.1/1000 cases of colorectal cancer. Initially reported in 1933, it has mostly been described in case reports. In contrast to anal cancer, human pallilomavirus (HPV) has no association with rectal SCC. Most cases of rectal SCC are localized and early-stage at diagnosis. Symptoms can include rectal bleeding or altered bowel habits, although our patient was unusually asymptomatic. Diagnosis is made with endoscopic biopsy. PET scan can be helpful in ruling out an external primary SCC. Given the paucity of cases, the optimal treatment strategy is currently unknown. Although historically treated with surgical resection, chemoradiation with the Nigro protocol, a standard treatment for anal SCC, has recently shown success in rectal SCC due to overall survival as well as sphincter preservation. Further research into the optimal treatment of this rare malignancy is needed and we encourage reporting of future cases of rectal SCC.


Figure: Figure 1: A. CT imaging demonstrating right rectal wall mass measuring 4.8 cm AP x 4.1 cm transverse. B. CT imaging 3 months later demonstrating marked decrease in tumor size to a soft tissue rectal wall prominence. C. Endoscopy image demonstrating erythematous nodular friable mass in the rectum. D. H&E stain (10x) showing SCC on the surface and columnar colorectal mucosa (crypts) in the lamina propria.


Disclosures:
Hunza Chaudhry indicated no relevant financial relationships.
Sunny Sandhu indicated no relevant financial relationships.
Sharon Zhang indicated no relevant financial relationships.
Devang Prajapati indicated no relevant financial relationships.


Hunza Chaudhry, MD¹, Sunny Sandhu, MD², Sharon Zhang, MD, PhD³, Devang N. Prajapati, MD, FRCPC⁴. P0198 - A Rare Case of Rectal Squamous Cell Carcinoma Treated With Nigro Protocol, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.