Analysis of tumor morphology in metastatic colorectal cancer: does this classification have any clinical significance?

Macroscopic classification of metastatic liver tumors has been recommended to predict patient prognosis. Methods: We examined the morphological analysis of metastatic colorectal cancer in 64 patients who underwent hepatic resection and the relationship with clinicopathologic factors. To identify the irregularity of the tumor, we calculated three formulas: (1) actual area of representative cut surface of tumor/circular length of tumor margin, (2) actual area of representative cut surface of tumor/elliptic area, defined by the major and minor axes, and (3) deviation of radius of marginal curvature. Results: Following Yasui's macroscopic classification, the values of formulas (1) and (2) in confluent nodules were significantly lower than those in simple nodules (P < 0.05), while the value of formula (3) in confluent nodules was significantly greater than that in simple nodules (P < 0.05). Only a lower value of formula (1) (less than 0.19) was significantly associated with postoperative recurrence (P < 0.05) and a lower value tended to be associated with a shorter disease-free survival after hepatectomy, but not significantly (P = 0.09). However, most values were not associated with any clinicopathologic factors or postoperative survival. Conclusions: We conclude that differences in the morphological irregularity of liver tumors in metastatic colorectal cancer do not have clinical significance.