A national retrospective study led by researchers at The University of Texas MD Anderson Cancer Center found no association between intensity of post-treatment surveillance and detection of recurrence or overall survival (OS) in patients with stage I, II or III colorectal cancer (CRC). Published in the Journal of the American Medical Association, the study is the largest of surveillance intensity in CRC ever conducted.

“These findings differ from historical data and argue to reconsider current guideline recommendations, in the U.S.” said George J. Chang, M.D., professor of Surgical Oncology and of Health Services Research.

According to the American Cancer Society, CRC is the second leading cause of cancer death in the U.S. and is expected to affect approximately 140,000 people in 2018. National and international consensus guidelines for post-treatment surveillance for recurrence vary considerably in frequency and reliance on groups of tests. Although many still recommend frequent testing, adherence to these guidelines is inconsistent, resulting in both over- and under-testing in clinical practice, explained Chang.
“There is limited evidence to inform the current guidelines for follow-up testing after curative treatment of colon and rectal cancer and this has resulted in large variations in surveillance guidelines,” said Chang, the study’s corresponding author. “We sought to improve our understanding of the optimal approach to follow-up testing including how often that testing should be done.”

For the retrospective cohort study, Chang and colleagues analyzed data from 8,529 randomly selected adult patients. Data from the National Cancer Database linked with medical record data from a Commission on Cancer Special Study were evaluated to determine if there was an association between surveillance intensity and the detection of recurrence or OS within a large U.S. population outside a clinical trial. Patients were diagnosed with stage I (25.0 percent), stage II (35.2 percent) and stage III (39.8 percent) CRC and treated with surgery in 2006 or 2007, with follow-up through 2014.

Surveillance intensity was defined by the frequency of imaging scans (PET, CT, MRI) and blood tests for the carcinoembryonic antigen (CEA) biomarker during the first three years of surveillance. Patients treated at high-intensity facilities experienced an average of 2.9 imaging scans and 4.3 CEA tests, while patients at low-intensity facilities underwent an average of 1.6 imaging scans and 1.6 CEA tests. The frequency of testing also varied by stage of disease.

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