INTRODUCTION

Colorectal cancer (CRC) is a common malignancy. Despite receiving potentially curative primary therapy, more than 40 percent of patients who present with stage II or III disease (table 1) will experience disease recurrence. (See "Adjuvant therapy for resected stage III colon cancer" and "Adjuvant therapy for resected rectal adenocarcinoma not treated with neoadjuvant therapy" and "Neoadjuvant therapy for rectal adenocarcinoma".)

There is variability among physicians in the use of follow-up studies after potentially curative resection of CRC, as well as in the guidelines from major societies and expert groups. Multiple surveillance strategies have been published at costs ranging from a few hundred to several thousand dollars per patient.

Intensive postoperative surveillance programs have been justified in the hope that early detection of asymptomatic recurrences will increase the proportion of patients who are potentially eligible for curative therapy. A survival benefit from such an approach has, in fact, been shown in several meta-analyses. Furthermore, periodic imaging can detect early, potentially resectable recurrences.

This topic review will cover the rationale for intensive post-treatment surveillance in the first five years after treatment, data on the effectiveness of various surveillance strategies, and recommendations for post-treatment surveillance in patients with resected CRC, including recommendations from expert groups. Recommendations for secondary prevention (dietary modification, exercise, and use of aspirin and other nonsteroidal anti-inflammatory drugs) and for the management of long-term CRC survivors are discussed separately. (See "The roles of diet, physical activity, and body weight in cancer survivors" and "Adjunctive therapy for non-metastatic treated colorectal cancer: Aspirin, NSAIDs, and vitamin D", section on 'Aspirin and other NSAIDs' and "Approach to the care of colorectal cancer survivors" and "Adjuvant therapy for resected stage III colon cancer", section on 'Adjunctive therapy' and "Adjunctive therapy for non-metastatic treated colorectal cancer: Aspirin, NSAIDs, and vitamin D".)

STAGE I DISEASE

There are no data available to guide post-treatment surveillance in patients with resected stage I colon or rectal cancer (table 1), and the recommendations of expert groups are variable. Consistent with updated American Society of Clinical Oncology (ASCO) guidelines [1], we do not pursue post-treatment surveillance for most asymptomatic patients with resected stage I CRC, except for interval colonoscopy. However, some of these patients have higher-risk disease (eg, rectal cancer treated with endoscopic or transanal excision, colon cancers treated with endoscopic resection alone, and patients who did not undergo guideline-based treatment) for whom surveillance-based detection, as is used for higher-stage disease, might reveal a potentially salvageable recurrence.