BACKGROUND:Advances in the management of rectal cancer have resulted in an increased application of multimodal therapy with the aim of tailoring therapy to individual patients. Complete pathological response (pCR) is associated with improved survival and may be potentially managed without radical surgical resection. Over the last decade, there has been increasing interest in the ability of functional imaging to predict complete response to treatment. The aim of this review was to assess the role of (18)F-flurordeoxyglucose positron emission tomography (FDG-PET) in prediction of pCR and prognosis in resectable locally advanced rectal cancer. METHODS:A search of the MEDLINE and Embase databases was conducted, and a systematic review of the literature investigating positron emission tomography (PET) in the prediction of pCR and survival in rectal cancer was performed. RESULTS:Seventeen series assessing PET prediction of pCR were included in the review. Seven series assessed postchemoradiation SUVmax, which was significantly different between response groups in all six studies that assessed this. Nine series assessed the response index (RI) for SUVmax, which was significantly different between response groups in seven series. Thirteen studies investigated PET response for prediction of survival. Metabolic complete response assessed by SUV2max or visual response and RISUVmax showed strong associations with disease-free survival (DFS) and overall survival (OS). CONCLUSION:SUV2max and RISUVmax appear to be useful FDG-PET markers for prediction of pCR and these parameters also show strong associations with DFS and OS. FDG-PET may have a role in outcome prediction in patients with advanced rectal cancer.

Implantation metastasis of colorectal cancer in an anal fistula is very rare. We report a case of a 61 years old male who underwent fistulectomy for an anal fistula. Histopathology unexpectedly revealed adenocarcinoma in the fistula track, however the patient refused further treatment. Sixteen months later he presented with an obstructing locally advanced rectosigmoid cancer found to be fixed into the pelvic wall. An ileosigmoid bypass was fashioned and he was treated with neoadjuvant chemoradiotherapy followed by high anterior resection. Histopathology confirmed a colorectal adenocarcinoma, Immunohistochemistry of the tumors from both sites was CK7-/CK20+. The patient died 34 months later with liver and lung metastasis however no perianal recurrence occurred. Local resection with or without radiotherapy, instead of abdominoperineal resection, was feasible for control of perianal metastatic lesion implanted from colorectal cancer if local extended resection was possible.

Background Robot-assisted laparoscopic surgery is being performed more frequently for the minimally invasive management of rectal cancer. The objective of this meta-analysis was to compare the clinical and oncologic safety and efficacy of robot-assisted versus conventional laparoscopic surgery. Methods A search of the Medline and Embase databases was performed for studies that compared clinical or oncologic outcomes of conventional laparoscopic proctectomy with robot-assisted laparoscopic proctectomy for rectal cancer. The methodological quality of the selected studies was critically assessed to identify studies suitable for inclusion. Meta-analysis was performed by a random effects model and analyzed by Review Manager. Clinical outcomes evaluated were conversion rates, operation times, length of hospital stay, and complications. Oncologic outcomes evaluated were circumferential margin status, number of lymph nodes collected, and distal resection margin lengths. Results Eight comparative studies were assessed for quality, and seven studies were included in the meta-analysis. Two studies were matched case-control studies, and five were unmatched. A total of 353 robot-assisted laparoscopic surgery proctectomy cases and 401 conventional laparoscopic surgery proctectomy cases were analyzed. Robotic surgery was associated with a significantly lower conversion rate ( P = 0.03; 95% confidence interval 1–12). There was no difference in complications, circumferential margin involvement, distal resection margin, lymph node yield, or hospital stay ( P = NS). Conclusions Robot-assisted surgery decreased the conversion rate compared to conventional laparoscopic surgery. Other clinical outcomes and oncologic outcomes were equivalent. The benefits of robotic rectal cancer surgery may differ between population groups.

PURPOSE: This study was designed to determine the distance from the anal verge to the anterior peritoneal reflection in vivo, thereby improving the selection of patients for preoperative radiotherapy.METHODS: Measurement of the distance from the anal verge to the anterior peritoneal reflection, confluence of the taenia, and the origin of the sigmoid mesentery in 50 patients in the lithotomy position.RESULTS: The mean distance from the anal verge to the anterior peritoneal reflection was 11.9 cm (men) and 10 cm (women). To the origin of the sigmoid mesentery, the measurements were 18.8 cm (men) and 19.1 cm (women) and to the confluence of the taenia coli, 20.3 cm (men) and 18.8 cm (women).CONCLUSIONS: The distance from the anal verge to the origin of the sigmoid mesentery was approximately 19 cm in both men and women. Below this level tumors have limited mobility and should be amenable to radiotherapy.

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