(ChemotherapyAdvisor) – A CT morphologic response to preoperative chemotherapy is a dominant predictor of both overall survival (OS) and disease-free survival in patients who undergo hepatic resection for colorectal liver metastases, a study in the Journal of Clinical Oncology reported.

These results show that CT morphologic response to preoperative chemotherapy “may serve as an alternate outcome end point before hepatic resection,” noted Jean-Nicolas Vauthey, MD, of The University of Texas MD Anderson Cancer Center, Houston, TX, and colleagues.

The investigators analyzed preoperative prognostic factors in 209 patients who underwent hepatic resection of colorectal metastases after preoperative chemotherapy with oxaliplatin- or irinotecan-based regimens with or without bevacizumab. Radiologic responses were classified as optimal or suboptimal according to morphologic response criteria.

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“An optimal morphologic response was observed in 47% of patients treated with bevacizumab and 12% of patients treated without bevacizumab (P<0.001),” Dr. Vauthey noted. In the optimal response group, OS was 82% at 3 years and 75% at 5 years vs 60% and 45%, respectively, in the suboptimal response group (P<0.001).

Multivariate analysis found suboptimal morphologic response to be an independent predictor of worse OS (HR 2.09; P=0.007), whereas optimal morphologic response was significantly associated with receipt of bevacizumab (OR 6.71; P<0.001) and largest metastasis ≤3 cm prior to chemotherapy (OR 2.12; P=0.025).

The study also demonstrated that suboptimal morphologic response, node-positive primary tumor, and positive surgical margins were most strongly associated with poor prognosis after resection of colorectal liver metastases.

“The morphologic response showed no specific correlation with conventional size-based RECIST criteria, and it was superior to RECIST in predicting major pathologic response,” they concluded.