Response to Neoadjuvant Chemoradiotherapy in a Patient with Mucinous Adenocarcinoma Arising from a Chronic Anorectal Fistula and Diagnosed by Transrectal Punch Biopsy: A Case Report

Mucinous adenocarcinoma arising from a chronic anorectal fistula is a rare condition. It is often confused with a hemorrhoid or perineal abscess, which consequently delays accurate diagnosis. Here, we report the case of a 58-year-old man with blood-tinged stool who reported a rectal mass, which was diagnosed as mucinous adenocarcinoma arising from an anal fistula. After initial computed tomography-guided needle aspiration biopsy had failed to provide an accurate diagnosis, transrectal punch biopsy was performed to obtained adequate tissue sample for confirmative histological diagnosis. The patient was successfully treated with neoadjuvant concurrent chemoradiotherapy followed by surgical intervention.

Positional Reproducibility and Effects of a Rectal Balloon in Prostate Cancer Radiotherapy

Despite the increasing use of the rectal balloon in prostate cancer radiotherapy, many issues still remain to be verified objectively including its positional reproducibility and relevance to treatment morbidity. We have developed a custom rectal balloon that has a scale indicating the depth of insertion and dilates symmetrically ensuring positional reproducibility. Fifty patients with prostate cancer treated by definitive 3D-conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) with rectal balloon were analyzed. Each of first five patients undergone computed tomography (CT) three times with a rectal balloon. The positional reproducibility was tested by Intraclass Correlation Coefficient (ICC) from the CT-to-CT fusion images. Planning variables and clinical acute toxicities were compared between when or not applying balloon. An ICC of greater than 0.9 in all directions revealed an excellent reproducibility of the balloon. Rectal balloon improved considerably the mean dose and V(45Gy)-V(65Gy) in plan comparison, and especially in 3D-CRT the rectal volume exposed to more than 60 Gy dropped from 41.3% to 19.5%. Clinically, the balloon lowered acute toxicity, which was lowest when both the balloon and IMRT were applied simultaneously. The rectal balloon carries excellent reproducibility and reduces acute toxicity in 3D-CRT and IMRT for prostate cancer.