CLOCC Study Final Results: Does Local Treatment Increase Survival Time?

Patients with unresectable colorectal liver metastases survive longer if they are treated with a combination of systemic treatment and local treatment with radiofrequency ablation and with or without resection, according to the final results of the CLOCC study.

The phase II, randomized trial compared combination treatment with systemic treatment alone in 119 patients with nonresectable colorectal liver metastases without extrahepatic disease. In 2012, a primary analysis with a median of 4.4 years of follow-up was published, which showed that patients had a 30-month overall survival rate of 38%.

The new analysis covered a median of 9.7 years of follow up and showed that a higher percentage of deaths occurred in the systemic treatment alone arm, in which 53 of 59 patients (89.9%) died. In the combined modality arm, 65% (39 of 60) of patients died in the 9.7-year period. Overall, 77.3% of patients included in the study (92 of 119) died during the 9.7-year follow-up period. The vast majority of the deaths were due to progressive disease, the researchers noted.

In the combined modality group, overall survival after 3 years was 56.9% (95% CI = 43.3% to 68.5%), after 5 years was 43.1% (95% CI = 30.3% to 55.3%) and after 8 years was 35.9% (95% CI = 23.8% to 48.2%).

In contrast, the systemic treatment group had an overall survival rate of 55.2% (95% CI = 41.6% to 66.9%) after 3 years, 30.3% (95% CI = 19% to 42.4%) after 5 years, and 8.9% (95% CI = 3.3% to 18.1%) after 8 years.

The median overall survival rate was also higher in the combined treatment group (45.6 months) compared with the systemic treatment group (40.5 months).

According to the study’s authors, “these data strongly suggest that the combined modality of aggressive local tumor treatment in combination with systemic treatment can change the outcome of these patients considerably with a clear benefit on overall survival.”

They added, “This encourages the early integration of local ablative techniques alone or in combination with surgical resection in patients with unresectable colorectal liver metastases, as should be discussed in a multidisciplinary team setting.”


Ruers T, Van Coevorden F, Punt CJA, et al. Local treatment of unresectable colorectal liver metastases: results of a randomized phase II trial. JNCI J Natl Cancer Inst. 2017;109(9):djx015.