How often should colorectal cancer patients be checked for recurrence?

This study examined how often surveillance colonoscopies should be performed following curative surgery for colorectal cancer (CRC).

In the years following curative surgery for colorectal cancer (surgery to remove all of the tumor and nearby affected tissues) surveillance tests such as colonoscopies and imaging scans are performed to detect recurrence of the disease. Colonoscopy involves insertion of a long tube with a camera into the colon through the anus. Colonoscopies allow early detection and removal of suspicious lesions, which can develop into a recurring cancer. In the United States, it is recommended that these surveillance colonoscopies be performed at 1, 4, and 9 years after surgery. The current study wished to determine whether frequent surveillance colonoscopies are truly necessary, and when is the best time for these to be preformed. 

This study examined the records of 671 patients who underwent curative surgery for CRC, and reviewed the timing and results of surveillance colonoscopies. Records were followed for five years following surgery.

Of the patients examined, 73% had their first surveillance colonoscopy 6-18 months after surgery. Local recurrence (a return of the original cancer in the same area) was detected in three patients (0.7%), all at the first surveillance colonoscopy performed after surgery. New cancers (not originating from the original cancer) were detected in 8% of the patients. These were detected in both the first, and the second (preformed 3-5 years after surgery), surveillance colonoscopies.

In summary, since recurrence rate was shown to be low, this study concluded that surveillance colonoscopies should be performed at 1 year after surgery, and again 3 to 4 years after surgery. Surveillance colonoscopies should aim at detecting new cancerous growths as well as recurrence of the original cancer.

This study was performed at a single medical center. Since colonoscopies are technical procedures, the quality of the exam depends on the doctor performing the procedure. Hence, performing the same trail at a different center with different staff is likely to produce different results. A multicenter trial would have provided more reliable results.

Consult with your physician regarding the optimal timing of colonoscopies to detect cancer recurrence after surgery.