Conversion to Resection in Patients Receiving Systemic Chemotherapy for Unresectable and/or Metastatic Colorectal Cancer-Predictive Factors and Prognosis

Abstract

Background: Systemic chemotherapy increases the possibility of resection in patients with initially unresectable colorectal cancer (CRC), especially patients with hepatic metastasis. However, the predictive factors and prognosis of conversion to resection after chemotherapy in patients with various organ metastases remain largely unknown.

Patients and methods: We reviewed the data from metastatic CRC (mCRC) patients who had received oxaliplatin- or irinotecan-based systemic chemotherapy from 2005 to 2016. The predictors for conversion to surgery were assessed by multivariate analyses. Cancer-free survival and overall survival after the initiation of treatment were compared between patients who had undergone successful conversion therapy and those who had undergone surgery first for resectable stage IV CRC.

Results: Of 99 mCRC patients receiving first-line chemotherapy, 23 underwent secondary surgical resection. Single organ metastasis, the presence of liver metastases, and the use of biologic agents were independent predictors of successful conversion therapy. The long-term survival of patients who underwent successful secondary surgery did not differ significantly from that of the 112 patients with resectable stage IV CRC who had undergone surgery first.

Conclusion: Liver metastases and single organ metastasis were more likely to be resected after chemotherapy than were other metastatic lesions in mCRC. The use of biologic agents contributed to the increased conversion rate. Successful conversion resulted in outcomes similar to those of resectable stage IV CRC.

Keywords: Chemotherapy; Colorectal cancer; Conversion therapy; Predictive factors; Prognosis.