Marginal statistical evidence of efficacy of adjuvant and/or perioperative chemotherapy after resection of colorectal metastases exists, but formal recommendations are still lacking. The present study evaluated the adjuvant systemic chemotherapy after the first resection of liver and lung colorectal cancer metastases.

We retrospectively reviewed data of 181 consecutive unselected patients with R0 resection of colorectal metastases treated simultaneously at 2 institutions from 1997 to 2004. Patients > 75 years old, with an Eastern Cooperative Oncology Group Performance Status Score ≥ 2 or unfit for adjuvant chemotherapy were excluded from the analysis. The decision on chemotherapy after surgery was left to the patient in the absence of conclusive data on the efficacy of adjuvant chemotherapy in this setting. A total of 151 patients (131 with liver metastases, 20 with lung metastases), 78 of whom underwent adjuvant chemotherapy, were evaluable for disease-free survival (DFS) and overall survival. The main prognostic factors for DFS after resection of colorectal cancer metastases were investigated in univariate and multivariate analyses.

At the univariate analysis, the number of resected lesions, lesion volume, disease-free interval and adjuvant systemic chemotherapy were the only significant prognostic factors. At multivariate analysis, only adjuvant chemotherapy and disease-free interval were independent prognostic factors (hazard ratios 1.66 and 1.62, respectively). The median DFS of patients who underwent systemic adjuvant chemotherapy was 16 months compared with 9.7 months for patients with observation alone (hazard ratio 1.56). Estimated 5-year DFS was 17.4% and 10.5% for treated and untreated patients, respectively.

Adjuvant chemotherapy after metastasectomy in patients with colorectal cancer showed a significant benefit for DFS.