PURPOSE Some metastatic colorectal cancer (mCRC) patients receive conversion surgery (CS), including metastasectomy after palliative chemotherapy. Although targeted agents significantly improved the outcomes, the clinical outcome of CS in the targeted agent era has not yet been thoroughly investigated.

METHODS We analyzed the clinical data of 96 mCRC patients who initially had unresectable liver- and/or lung-limited metastases and underwent first-line cetuximab or bevacizumab plus FOLFIRI between January 2013 and June 2017.

RESULTS Liver-limited metastasis was seen in 44 patients (45.8%), lung-limited metastases in 21 patients (21.9%), and both liver and lung metastases in 31 patients (32.3%). Among them, 37 patients (38.5%) received cetuximab, and 59 patients (61.5%) received bevacizumab plus FOLFIRI. Overall response rate was 63.9% and 40.7%, respectively (p = 0.035). After median 8.7 (range 2.5-27.3) months, CS was performed in 11 patients (29.7%) in cetuximab group and 15 patients (25.4%) in bevacizumab group (p = 0.646). Median overall survival has not been reached in R0-resected patients (n = 23), during the median follow-up period of 22.5 (range 9.8-54.5) months. Median disease-free survival was 7.1 (95% CI 2.5-11.7) months: 11.0 (95% CI 3.1-19.0) months in cetuximab group and 3.2 (95% CI 0.0-7.8) months in bevacizumab group (p = 0.422). There was no progression after 18.5 months and disease-free survival reached a plateau at 19.9%.

CONCLUSIONS A substantial proportion of patients could receive CS after cetuximab or bevacizumab plus FOLFIRI chemotherapy. R0-resected patients had excellent overall survival, although 80.1% of them eventually experienced recurrence. Some patients could achieve durable disease-free state.