Metastasectomy in patients with non-resectable metastatic colorectal cancer receiving chemotherapy and anti-EGFR antibodies: a prospective, non-randomized, multicenter, phase II study

Objective: to analyze the frequency of metastasectomy in general population of patients with RAS wild-type metastatic colorectal cancer who received chemotherapy and anti-EGFR monoclonal antibodies

Materials and methods. This prospective, non-randomized, multicenter study was designed to evaluate the frequency of resections of organs affected by metastasis. Our statistical hypothesis was that the addition of anti-EGFR antibodies should increase the frequency of metastasectomy from 5% to 15 %. Sample size calculations showed that to obtain a power of 80 % and an alpha level of 0.05 to detect the difference, we would need to recruit 50 patients. The primary endpoint was the frequency of resections of organs affected by metastasis, whereas the secondary endpoints included objective response rate, progression-free survival, and length of live. Tolerability of the therapy was analyzed separately.

Results. Eighteen out of50 (36 %) patients achieved objective response; 32 (64 %) patents achieved stable disease and 18 (36 %) patients had disease progression. Radical resection of organs affected by metastasis was performed in 8 out of 50 patients (16 %): 1 individual had lung resection and 7 individuals had liver resection. Among participants with isolated liver lesions, the frequency of metastasectomy was 24 % (6 out of 25 patients). At a median follow-up of 14 months (between 1 and 34 months), median progression-free survival was 8 months (95 % confidence interval 6.2—9.8) and median length of life was 26 months (95 % confidence interval 19.7—32.2). The estimated 2-year overall survival was 83 % in patients who underwent metastasectomy vs. 51 % in those who had no metastasectomy.

Conclusions. The addition of anti-EGFR monoclonal antibodies to standard combination chemotherapy (FOLFOX/FOLFIRI) increases the frequency of metastasectomy in patients with non-resectable metastatic colorectal cancer, which results in an increased length of life.

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