Surveillance after curative treatment for colorectal cancer.

Treatments for colorectal cancer (CRC) of all stages have evolved considerably over the past two decades, resulting in improved long-term outcomes. After curative treatment, however, 30% of patients with stage I-III and up to 65% of patients with stage IV CRC develop recurrent disease. Thus, patients are routinely offered surveillance in order to detect disease recurrence at an early, asymptomatic stage, with the intention of improving survival. Nevertheless, controversy continues to surround the optimal surveillance protocols. For patients with stage I-III CRC, more-intensive surveillance improves overall survival compared with less-intensive or no surveillance, probably owing to improved outcomes after cancer recurrence, as well as proactive treatment of other conditions detected opportunistically. The benefit of surveillance after curative treatment of stage IV CRC is more controversial, but might be justified because repeat resection can improve overall survival and 20% of these patients are eligible for such treatment with curative intent. No trials have assessed the optimal follow-up approach after curative resection of metastatic CRC, and similarly to surveillance of patients with stage I-III disease, most programmes are more intensive during the first 3 years than at later time points. Herein, we provide a comprehensive overview of surveillance strategies for patients with CRC, and discuss the future development of patient-centred programmes.