Reporting colorectal cancer.

The management of colorectal cancer is a team process. High-quality reporting of colorectal cancer is very important as the whole team relies upon the skill of the pathologist. Failure to report key features can lead to undertreatment of this disease. The use of a proforma has been demonstrated to be beneficial and we recommend staying with TNM5 due to scientific and reproducibility issues with TNM6. Important features in stage II/Dukes' B cases are extramural vascular invasion, peritoneal involvement, extent of extramural spread, incomplete resection and perforation. All of these may lead to adjuvant therapy being administered. The surgically created circumferential resection margin (CRM) and the mode of its creation are important features and the CRM retains its value after preoperative therapy. Regression grading should be applied only to fully resected tumours and the dissection and sampling must be standardized to allow comparison of results between trials and centres. When reporting local resections of early-stage cancers we need to look for features that predict spread to local lymph nodes to allow a full resection to be considered.