Metachronous metastases from colorectal cancer: a population-based study in North-East Netherlands

The main cause of death of colorectal cancer patients is metastatic disease. Approximately 20-25% of the patients present with metastases at time of diagnosis. The clinical course of patients who develop metachronous metastases, however, is less clear. The aims of this study were to describe the incidence, treatment and survival of patients with metachronous metastases from colorectal cancer and to determine risk factors for developing metachronous metastases.

From the Netherlands Cancer Registry, patients diagnosed with colorectal carcinoma in the period 2002-2003 in North-East Netherlands were selected. Patients were followed for 5 years after diagnosis of the primary tumour. Kaplan-Meier method and Cox regression analyses were used to determine predictors for developing metastases and to analyse overall survival.

In total, 333 of 1743 (19%) patients developed metachronous metastases. The majority (83%) of these metastases were diagnosed within 3 years, and the most frequent site was the liver. Patients with advanced stage and patients with tumours in the descending colon or in the rectum were more likely to develop metastases. Approximately 10% of all patients underwent intentionally curative treatment for their metastases, with a 5-year survival rate of 60%. Treatment of metastases and pathologic N (pN) status were independent prognostic factors for overall survival.

Site and stage of the primary tumour were predictors for developing metachronous metastases. A limited number of patients with metastatic disease were treated with a curative intent. These patients had a good prognosis. Therefore, focus should be on identifying more patients who could benefit from curative treatment.