[Colorectal cancer]

Recent advances in chemotherapy and chemoradiation therapy for colorectal cancer have made neoadjuvant treatment an eligible therapeutic option for selected cases of marginally resectable colorectal cancer. However, marginally resectable colorectal cancer is not well defined. The authors suggest that a primary lesion is marginally resectable if extended resection such as pelvic exenteration and pancreaticoduedenectomy are not completely curative. Even if the lesion itself is resectable, it is marginally resectable if it has unfavorable prognostic factors such as numerous metastases to the regional lymph nodes. Rectal cancer invading beyond mesorectal fascia, or having bilateral or multiple lateral lymph node metastasis, may also be marginally resectable. All locally recurrent lesions may be marginally resectable because the prognosis after surgical resection is poor. Multiple liver metastases, liver metastasis for which resection requires vascular reconstruction, and technically resectable liver metastasis with unfavorable prognostic factors, are also thought to be marginally resectable. Neoadjuvant chemotherapy regimens including oxaliplatin and irinotecan combined with bevacizumab, cetuximab and panitumumab may be effective for hastening the curability of such marginally resectable tumors. For primary advanced rectal cancer and locally recurrent rectal cancer, neoadjuvant radiation combined with chemotherapy using oxaliplatin and irinotecan are being explored. A number of clinical trials are currently ongoing, and are expected to clarify the effectiveness of neoajuvant treatment for marginally resectable colorectal cancer.