Tumor histopathology predicts outcomes after resection of colorectal cancer liver metastases treated with and without pre-operative chemotherapy.

ABSTRACT

BACKGROUND AND OBJECTIVES: Study objectives, included determination of (i) associations between radiologic and pathologic responses of colorectal cancer liver metastases (CRCLM) to chemotherapy; and (ii) whether CRCLM histopathology is associated with recurrence free survival (RFS) after resection among patients not treated with pre-operative chemotherapy (untreated). METHODS: Demographics, clinicopathologic characteristics, and outcomes among patients who underwent CRCLM resection from 2007 to 2014 were reviewed. Tumor regression grade (TRG) of 1-2 and 4-5 depict low and high proportions of viable tumor relative to fibrosis, respectively. RESULTS: Of 138 patients, 84 (60.9%) were treated with pre-operative chemotherapy. In these patients, there was no difference in proportions with TRG 1-2 among those with verses without radiologic response (26.9% vs. 18.8%, P = 0.393). TRG 1-2 was associated with superior RFS on univariable (median 15 vs. 6 months, P < 0.001) and multivariable (P = 0.005) analyses. Radiologic response was not associated with RFS. Among untreated patients (n = 54), TRG 4-5 was associated with poor RFS on univariable (median 44 vs. 15 months, P = 0.011) and multivariable (P = 0.012) analyses. CONCLUSIONS: High proportions of CRCLM fibrosis occur in 20% of patients without radiologic response to chemotherapy. Among untreated patients, high proportion of viable tumor relative to fibrosis is associated with poor RFS after resection. J. Surg. Oncol. 2016;113456-462. © 2016 Wiley Periodicals, Inc.