In this year’s NCCN Asia Colorectal Cancer Conference, Prof. Vennook from the University of California, San Francisco and Prof. Engstrom from FoxChase Cancer Center, Philadelphia, USA, presented on the updates to the 2011 edition of the NCCN clinical practice guidelines for colon and rectal cancer, respectively. Colon cancer guideline updates Professor Vennook noted that although the new colon cancer guidelines have been updated three times this year, there are no prominent treatment regimen recommendations and only refinements in pathology and molecular markers. The new guidelines remove the phrase “calcium levulinate (LV) is not approved for colon cancer treatment in the United States” and suggest that 400 mg/m2 of LV is equivalent to 200 mg/m2 of levulinate LV. weakening. The 18qLOH PETACC3 study analyzed chromosome 18 heterozygous deletion (18qLOH) in patients with stage II colon cancer and showed that 18qLOH was absent in patients with microsatellite stability (MSS) and present in 18% of patients with high microsatellite instability (MSI-H). Following last year’s recommendation that mismatch repair should be performed when considering FU-based chemotherapy in patients with stage II colon cancer Following last year’s recommendation to test for mismatch repair when considering FU-based chemotherapy for patients with stage II colon cancer, the 2011 edition of the guidelines recommends that MSI testing should be performed along with 18qLOH testing for further evaluation of patient prognosis. The ongoing E5202 study, which stratifies patients according to 18qLOH and microsatellite stability, is expected to reveal the role that 18qLOH and MSI play in the chemotherapy of stage II colon cancer. Chemotherapy regimens The FOLFOX regimen is recommended as the treatment of choice for patients with T1-3N1-2M0 or T4N1-2M0. The OXL+FU+folinic acid (FLOX) regimen is also recommended as Class I evidence and OXL combined with capecitabine as Class II evidence. For patients with advanced or metastatic colon cancer suitable for high-intensity therapy, capecitabine in combination with bevacizumab is recommended, as is irinotecan in combination with the OXL regimen. Pathological assessment Mutations in codons 12 and 13 of the KRAS gene are currently thought to be predictive of tumor failure to EGFR-targeted therapy. However, the results of a 2010 study suggest that patients with codon 13 mutations in the KRAS gene can still benefit from cetuximab therapy, which may be a part of future guideline updates. The recommendation for the BRAF gene is an important update. those with BRAF mutations have a poor prognosis, and retrospective analyses have shown that patients may benefit from first-line application of anti-EGFR-targeted therapy in combination with chemotherapy, regardless of the presence of a BRAF mutation. A limited number of studies have shown that EGFR monotherapy is less effective in patients with BRAF mutations who have progressed after first-line treatment. Rectal cancer guideline update Professor Engstrom noted that prominent treatment issues in rectal cancer include increased local recurrence, the value of neoadjuvant and adjuvant therapy, preservation of the sphincter and issues of urinary and sexual dysfunction. TNM staging The new guidelines refine the TNM staging of rectal cancer. t4 is divided into T4a (lesions penetrating the dirty peritoneum) and T4b (lesions invading adjacent organs or tissues), with the addition of N1c (lesions located in the subplasma layer, mesentery or peri-rectal tissues not covered by peritoneum, without local lymph node metastasis), and N2 is divided into N2a (local metastasis of 4-6 lymph nodes) and N2b ( ≥7 lymph node metastases), and M1 was divided into M1a and M1b according to the cumulative number of organs. Surgical procedure Although several studies have confirmed the value of laparoscopic surgery in the treatment of rectal cancer, laparoscopic radical surgery is still not recommended in the new edition of the guidelines. For lesions clearly confined to the rectum (especially proximal), a new recommendation for minimally invasive transanal endoscopic surgery (TEM) has been added. Postoperative treatment The new version of the guidelines adds a variety of treatment options for postoperative adjuvant therapy in patients with pT3N0M0 or pT1-3N1-2, including radiotherapy with continuous FU titration or FU+LV regimen, capecitabine ± OXL and FOLFOX regimen, and capecitabine in combination with OXL has also become a new option for postoperative adjuvant therapy. For patients with resectable stage M1 metastases of any T and N, the capecitabine combined with OXL regimen was added. Pathology reports The guidelines emphasize that the pathology report of rectal cancer should include a description of the status of the peri-annular resection margin. Studies have shown that total rectal mesenteric resection has a significantly lower rate of local recurrence compared to conventional surgery. Therefore, the guidelines require not only a determination of postoperative mesenteric integrity, but also information on the patient’s response to neoadjuvant chemotherapy.