Ex vivo specimen MRI and pathology confirm a rectosigmoid mesenteric waist at the junction of the mesorectum and mesocolon.

AIM: Continuity of the mesentery has recently been established and may provide an anatomical basis for optimal colorectal resectional surgery. Preliminary data from operative specimen measurements suggest there is a tapering in the mesentery of the distal sigmoid. A mesenteric waist in this area may be a risk factor for local recurrence of colorectal cancer. This study aimed to investigate the anatomical characteristics of the mesentery at the colorectal junction. METHOD: In this cross-sectional study, 20 patients were recruited. After planned colorectal resection, the surgical specimens were scanned in a MRI system and subsequently dissected and photographed as per national pathology guidelines. Mesenteric surface area and linear measurements were compared between MRI and pathology to establish the presence and location of a mesenteric waist. RESULTS: Specimen analysis confirmed that a narrowing in the mesenteric surface area was consistently apparent at the rectosigmoid junction. Above the anterior peritoneal reflection, the surface area and posterior distance of the mesentery of the upper rectum initially decreased before increasing as the mesentery of the sigmoid colon. These anatomical properties created the appearance of a mesenteric 'waist' at the rectosigmoid junction. Using the anterior reflection as a reference landmark, the rectosigmoid waist occurred at a mean height of 23.6 and 21.7 mm on MRI and pathology, respectively. CONCLUSION: A rectosigmoid waist occurs at the junction of the mesorectum and mesocolon, and is a mesenteric landmark for the rectum that is present on both radiology and pathology.

The MRI assessment of SPECC (significant polyps and early colorectal cancer) lesions.

The development of high-resolution magnetic resonance imaging (MRI) has resulted in the ability to clearly depict the finer details of rectal wall anatomy. Careful specialist assessment of images obtained in patients with significant polyps and early rectal cancer lesions enables the identification of lesions that are confined to the bowel wall and amenable to organ preserving local excision. Currently, one-third of screen detected rectal cancers are limited to the bowel wall without nodal spread yet more than 90% undergo major excision surgery resulting in significant loss of bowel function, quality of life and at high economic cost. The SPECC initiative has highlighted the need for specialist training and accreditation of radiology specialists in precision assessment of significant polyps and early rectal cancer. The detailed assessment will enable provision of detailed roadmaps for surgeons and gastroenterologists to facilitate definitive excision of more lesions using minimally invasive endoscopic technique. Finally, the use of high resolution MRI in surveillance will enable the close monitoring of such patients where the preservation of the rectum has been achieved.

Variation in landmarks for the rectum: an MRI study.

AIM: This study aimed to assess the reliability of measurements and bony landmarks for the rectosigmoid junction on MRI. METHOD: The staging MRI scans for 100 patients were reviewed. The junction of the mesorectum and mesocolon was used to identify the rectum and sigmoid. The performance of current metric measurements or bony landmarks was then compared against the actual anatomical bowel segment. RESULTS: The mean distance of the sigmoid take-off from the anal verge was 12.6 cm (SD 1.8 cm, range 9.4-19.0 cm). At a cutoff of 12 cm, the anatomical bowel segment was found to be sigmoid colon rather than rectum in 35% of patients. At 15 and 16 cm the bowel segment was sigmoid in 84% and 96% of patients, respectively. At the sacral promontory and the third sacral segment, the bowel segment was sigmoid in 28% and 100% of patients, respectively. CONCLUSION: Current definitions of the rectum that rely on arbitrary measurements or bony landmarks will not locate the correct point of transition between the rectum and sigmoid in the majority of patients. The sigmoid take-off offers an alternative, anatomically bespoke, landmark.

Session 3: Boosting primary and recurrent rectal cancer: how far can we push the radiotherapy envelope?

Neoadjuvant pelvic radiotherapy is widely used for patients with advanced rectal cancer. The trade-off between dose and response is well-established, yet little consensus remains on the precise methods of delivery and doses given in different scenarios. Professor Vuong reviews the evidence base and trial evidence on the escalation of radiotherapy dose and the methods of achieving this.

Session 2: Extramural vascular invasion and extranodal deposits: should they be treated the same?

Professor Nagtegaal has already highlighted that lymph nodes are probably not responsible for the development of liver metastases. If they are not, then is there another mechanism? Professor Haboubi addresses the question of extranodal deposits - their frequency and their importance in the development of metastatic disease. The experts review the evidence and discuss whether this information will alter treatment decisions and staging systems in the future.

[The possibilities of treatment of recurrent colorectal cancer with sacral invasion]. / Vozmozhnosti lecheniya retsidiva raka pryamoi kishki s invaziei v krestets (s kommentariem).

AIM: To describe current methods of surgical treatment of rare form of recurrent rectal cancer with sacral invasion. MATERIAL AND METHODS: The article presents the methodology for the treatment of patients with recurrent colorectal cancer and sacral invasion using preoperative chemoradiotherapy followed by high-tech surgery of recurrent tumor removal with sacral resection at various levels (including high intersection at S1 level). CONCLUSION: It was concluded that chemoradiotherapy is indicated in patients with recurrent colorectal cancer if it was not made at the first stage of treatment. Additional radiotherapy up to optimum overall focal dose prior to surgery is advisable in those patients who previously underwent radiotherapy with partial dose. This type of operations has high risk of complications and requires a personalized approach to the selection of patients. However, R0-resection is associated with favorable long-term prognosis, significantly increased survival and overall quality of life. Combined surgery for recurrent tumors with sacral invasion should be performed by multidisciplinary surgical team in specialized centers using current possibilities of anesthesiology and intensive care.

Short-course preoperative radiotherapy combined with chemotherapy, delayed surgery and local hyperthermia for rectal cancer: a phase II study.

PURPOSE: The aim of this study was to investigate the feasibility of short-course radiotherapy with oral capecitabine, hyperthermia and delayed surgery for neoadjuvant treatment of rectal cancer. METHODS: Patients with clinically staged T2-3N0-2M0 primary rectal cancer were included. All patients received short-course 25 Gy in 5 Gy fractions radiotherapy with capecitabine, local hyperthermia and metronidazole. Capecitabine 1000 mg/m2 twice a day was given on days 1-14. Local hyperthermia, 41-45 °C for 60 min, was performed on days 3-5. Metronidazole 10 g/m2 was administered per rectum on days 3 and 5. The time interval to surgery was not less than four weeks after neoadjuvant treatment. The primary end-point was pathological complete response (pCR). Secondary end-points included neoadjuvant treatment toxicity, tumour regression, surgical and oncological outcomes. RESULTS: A total of 81 patients were included in the analysis. Ten (12.3%) patients had grade 3 toxicity and one (1.2%) patient had grade 4 toxicity. Sphincter-sparing surgery was performed for 78 (96.3%) patients. There was no postoperative mortality. Postoperative complications occurred in 11 (13.8%) patients. Sixteen (20%) patients had a pCR. The median follow-up was 40.9 months. There were no local recurrences. Nine (11.1%) patients developed distant metastases. Three-year overall survival was 97% and the three-year disease-free survival was 85%. CONCLUSIONS: Short-course radiotherapy with chemotherapy, radiosensitizers and delayed surgery is a feasible treatment for rectal cancer and may lead to tumour regression rate comparable with long-course chemoradiation.

The results of local excision with or without postoperative adjuvant chemoradiotherapy for early rectal cancer among patients choosing to avoid radical surgery.

AIM: The study aimed to establish the oncological outcome of patients who opted for close surveillance with or without adjuvant chemoradiotherapy rather than radical surgery after local excision (LE) of early rectal cancer. METHOD: The Royal Marsden Hospital Rectal Cancer database was used to identify rectal cancer patients treated by primary LE from 2006 to 2015. All patients were entered in an intensive surveillance programme. RESULTS: Twenty-eight of 34 analysed patients had a high or very high risk of residual disease predicted by adverse histopathological features for which the recommendation had been radical surgery. Eighteen (52%) of the 34 had received radiotherapy following LE. Three-year disease-free survival for the 34 patients was 85% (95% CI 78.8%-91.2%) and overall survival was 100%. Twenty-two of 24 patients with a low tumour which would have required total rectal excision have so far avoided radical surgery and remain disease free at a median follow-up of 3.2 years. CONCLUSION: The findings suggest that with modern MRI and clinical surveillance radical surgery can be avoided in patients following initial LE of a histopathologically defined high risk early rectal cancer. These findings are comparable with those obtained after major radical resection and warrant further prospective investigation as a treatment arm in larger prospective trials.

Histopathological and radiological reporting in rectal cancer: concepts and controversies, facts and fantasies.

In rectal cancer patients, the stage of the disease, local spread and distant metastases status drive the treatment decisions to be made. Histopathology remains the gold standard, but preoperative staging, particularly magnetic resonance imaging (MRI), is pivotal for defining surgical planes and finding patients who could potentially benefit from preoperative regimes. Unfortunately, due to a lack of awareness, expertise and practise the quality of rectal cancer MRI and histopathology reporting varies among centres. This paper highlights the most important and frequently occurring radiological and histopathological discrepancies/mistakes to be aware of.