Long-Term Outcomes of Patients Undergoing Conversion Surgery After Induction Chemotherapy: Turkish Oncology Group Study

<i>Background and Objectives</i>: Conversion surgery for liver metastatic colorectal cancer (mCRC) has been associated with prolonged survival. This study aimed to evaluate the efficacy and safety of integrating biological therapies with fluorouracil-based induction chemotherapy in patients with isolated liver mCRC who subsequently underwent curative resection of both the primary tumor and liver metastases. <i>Materials and Methods:</i> This multicenter, retrospective study, conducted by the Turkish Oncology Group (TOG), included 116 patients from 11 tertiary centers who underwent conversion surgery following induction chemotherapy between 2009 and 2024. <i>Results:</i> The median age was 57 years, with 62% male patients. The median follow-up period was 55.3 months. The median progression-free survival (PFS) and overall survival (OS) were 21.1 and 53.7 months, respectively. No significant differences in PFS or OS were observed based on biological therapy use or tumor localization. Among patients with RAS/RAF wild-type tumors, PFS and OS were comparable between those receiving Anti-EGFR and Anti-VEGF therapy. In RAS/RAF mutant tumors, the addition of Anti-VEGF therapy did not confer a survival benefit. Factors associated with shorter PFS included advanced tumor stage (ypT3-T4), lymph node metastasis, and multiple metastases, while shorter OS was linked to advanced tumor stage and lack of objective response. <i>Conclusions:</i> Surgical resection plays a pivotal role in improving survival outcomes in patients with potentially resectable liver mCRC. Optimizing induction chemotherapy regimens may enhance conversion rates and prolong long-term survival. Further studies are needed to refine treatment selection based on tumor localization, mutation status, and molecular biomarkers.