Nomogram including chemotherapy response for prediction of intrahepatic progression-free survival in patients with colorectal liver metastasis through chemotherapy followed by radiofrequency ablation

Abstract

Background: Radiofrequency ablation (RFA) is being considered as the favorable treatment option for unresectable colorectal cancer liver metastases (CRLM) receiving chemotherapy, yet there still exist challenges for recurrence after RFA. The present study aims to establish an effective nomogram to predict intrahepatic progression-free survival (PFS) and select RFA candidates. Methods: Patients with unresectable CRLM treated with chemotherapy followed by RFA between 2010 and 2016 were enrolled in this study. The nomogram to predict intrahepatic PFS was established based on multivariable Cox regression analysis. The predictive performance of the nomogram was assessed according to the C-index, calibration plots and Kaplan–Meier curve. Results: Of a total of 158 patients, the earlier new intrahepatic metastases over local tumor progression were observed in 157 patients during the follow-up, and the mean intrahepatic PFS was 16.9 ± 1.4 months in the present cohort. The optimal cutoff value of tumor size after chemotherapy was identified as 16 mm by X-tile analysis. Based on multivariate analysis, independent prognostic factors for intrahepatic PFS included primary positive lymph nodes, multiple metastases, tumor size >16 mm, no primary lesion resection, mutant KRAS and PD response after chemotherapy. The nomogram was established to predict intrahepatic PFS based on all independent factors, which achieved favorable discrimination and calibration. Conclusion: This study firstly established the nomogram to predict intrahepatic PFS for unresectable CRLM patients receiving chemotherapy followed by RFA. It can facilitate the selection of RFA candidates, and help both surgeons and patients choose individualized regimens in the treatment decision.