A new strategy with a grading system for liver metastases from colorectal cancer

The optimal indications, including timing, for resection of liver metastases from colorectal cancer (CRCLM) remain controversial. The Japanese Society of Cancer of the Colon and Rectum has proposed "H-classification" based on the maximum size and number of CRCLM, and has advocated the "CRCLM-grade system", which involves adding the presence of primary lymph node metastasis status to H-classification. We evaluated clinicopathological factors in order to elucidate the optimal indications for and timing of hepatectomy.

Ninety-six patients who underwent initial hepatectomy for CRCLM between August 1995 and May 2009 were retrospectively analyzed with respect to characteristics of primary colorectal metastatic hepatic tumors, operation details and prognosis.

Multivariate analysis identified depth of invasion in primary colorectal cancer (within sub-serosal (non-se) vs. beyond serosal (se)) and CRCLM-grade as independent risk factors. We then performed analyses using the combination of non-se/se and CRCLM-grade. Kaplan-Meier analysis identified significant differences between non-se+gradeA and se+gradeA, between non-se+gradeB and se+gradeB, and between non-se+gradeC and se+gradeC groups.

We could retrospectively predict survival in CRCLM patients by adopting this new simple classification. This method may allow more precise assessment of operative indications and timing for both operations and perioperative adjuvant treatment.