Surgical aspects of conversion therapy for initially unresectatble colorectal liver metastases

Background: Although recent advances in surgery and chemotherapy have increasingly enabled hepatectomy in patients with initially unresectable colorectal liver metastases (CRLM), the treatment strategy has yet to be decided. Methods: Among 269 patients who underwent initial hepatectomy for CRLM, 42 patients with initially unresectable CRLM who received conversion chemotherapy followed by hepatectomy were identified. Treatment strategy: 1) Basically, parenchyma-sparing hepatectomy is recommended. 2) RFA is performed for deeply located small-sized tumors from the viewpoint of parenchyma-sparing strategy. 3) If the removal of all tumors could not be achieved by a single hepatectomy, specific techniques such portal vein embolization (PVE) or two-stage hepatectomy (TSH) were utilized. Results: The mean tumor number and size changed from 9.4 to 7.4 and 6.6 to 4.9 cm, and median CEA from 103.4 to 7.6 before and after chemotherapy. RFA was used in combination with hepatectomy in 10 patients. PVE and TSH were performed in 8 and 13 patients, respectively. Local recurrence after RFA was not observed. 5-year overall and disease-free survival were 34.2% and 12.9%, respectively. Among 32 patients who developed recurrence, repeat surgery was performed in 13 patients (41%), and their survival was significantly better than those who could not (p=0.0046). Conclusions: Conversion chemotherapy, hepatectomy with specific techniques including RFA, PVE and TSH, and repeat surgery for recurrence could contribute to increase resectability and prolonged survival for initially unresectable CRLM.