A New Surveillance Algorithm After Resection of Colorectal Liver Metastases Based on Changes in Recurrence Risk and...

The optimal surveillance strategy after resection of colorectal liver metastases (CLM) is unknown. We evaluated changes in recurrence risk after CLM resection and developed a surveillance algorithm.

Patients undergoing CLM resection during 1998 to 2015 were identified from a prospectively compiled database and analyzed if they had the potential for follow-up longer than the longest observed time to recurrence in this cohort. Changes in recurrence risk and risk factors for recurrence were evaluated. All statistical tests were 2-sided.

Among 2,105 patients who were initially identified and underwent CLM resection, the latest recurrence was observed at 87 months; 1,221 consecutive patients from 1998 through 2011 with the potential for at least 87 months of follow-up were included. The risk of recurrence was highest at 0 to 2 years after CLM resection, lower at 2 to 4 years after CLM resection, and steadily lower after 4 years after CLM resection. Factors associated with increased recurrence risk at the time of surgery were primary lymph node metastasis (hazard ratio [HR], 1.54; 95% CI, 1.21-1.97; P<.001), multiple CLM (HR, 1.31; 95% CI, 1.06-1.63; P=.015), largest liver metastasis diameter >5 cm (HR, 1.64; 95% CI, 1.23-2.19; P<.001), and RAS mutation (HR, 1.29; 95% CI, 1.04-1.59; P=.020). In patients without recurrence at 2 years, the only factor still associated with increased recurrence risk was RAS mutation. In those patients, the recurrence rate at 4 years was 59.3% in patients with RAS mutation versus 27.8% in patients with RAS wild-type (P=.019).

For patients who have undergone CLM resection, we propose surveillance every 3 to 4 months during years 0 to 2, every 3 to 4 months (if mutant RAS) versus every 4 to 6 months (if RAS wild-type) during years 2 to 4, and every 6 to 12 months if recurrence-free at 4 years.