Preoperative bevacizumab and volumetric recovery after resection of colorectal liver metastases

Background and Objectives: While preoperative treatment is frequently administered to CRLM patients, the impact of chemotherapy, with or without bevacizumab, on liver regeneration remains controversial. Methods: The early and late regeneration indexes were defined as the relative increase in liver volume (RLV) within 2 and 9 months from surgery. Regeneration rates of the preoperative treatment groups were compared. Results: Preoperative chemotherapy details and volumetric data were available for 185 patients; 78 (42.2%) received preoperative chemotherapy with bevacizumab (Bev+), 46 (24.8%) received chemotherapy only (Bev-), and 61 (33%) received no chemotherapy. Patients in the Bev+ and Bev- groups received similar chemotherapy cycles (4 [3-6] vs 4 [4-6]; P=0.499). Despite the comparable clinicopathological characteristics and Resected Volume/Total Liver Volume (TLV) at surgery (P=0.944) of both groups, Bev+ group had higher early and late regeneration (17.2% vs 4.3%; P=0.035 and 14.0% vs 9.4%; P=0.091, respectively). Of note, early and late regeneration rates (3.7% and 10.9% vs 6.6% and 5.5%, respectively) were comparable between the no chemotherapy and Bev- groups (all P>0.05). In multivariable analysis -adjusted for gender, age, portal vein embolization, preoperative chemotherapy, resected liver volume, tumor number, postoperative chemotherapy, fibrosis, steatosis- bevacizumab independently predicted early liver regeneration (P=0.019). Conclusion: Our findings suggest that preoperative bevacizumab administered along with chemotherapy was associated with enhanced volumetric restoration. Interestingly, this effect was more pronounced among patients who received oxaliplatin-based regimens and bevacizumab compared to those treated with irinotecan-based regimens and bevacizumab.