Results Summary

What was the research about?

Regular follow-up tests can help patients who have had surgery for colorectal cancer find out if the cancer has come back. These tests may include CT scans or other imaging scans and blood tests. But researchers don’t know if having more tests works better for patients than having fewer tests.

In this study, the research team compared health data for patients who received care at two types of clinics:

  • Clinics that gave patients more tests. At these clinics, patients received an average of 2.9 imaging scans and 4.3 blood tests over three years.
  • Clinics that gave patients fewer tests. At these clinics, patients received an average of 1.6 imaging scans and 1.6 blood tests over three years.

What were the results?

Being in a clinic that gave more or fewer tests made no difference in

  • How often tests found that patients’ cancer came back
  • How often patients had a second surgery to treat colorectal cancer
  • How likely patients were to live five years after their first surgery

Overall, after five years, 19 percent of patients had colorectal cancer that came back. Patients who had more advanced cancer were more likely to have cancer that came back.

Who was in the study?

The research team looked at data from a national cancer registry and health records for patients who had had surgery for stage I–III colorectal cancer between 2006 and 2007. Of these, 4,341 patients went to clinics that gave more tests, and 4,188 went to clinics that gave fewer tests. Among patients, 86 percent were white, 10 percent were African American, and 4 percent were of another race. The average patient age was 68, and 52 percent were women.

What did the research team do?

The research team looked at patient records to see how often patients got follow-up tests at 1,175 clinics. Then the team compared patients who had follow-up tests at clinics that gave more tests and clinics that gave fewer tests. The team looked at patients’ health for up to five years after their original surgery.

A group of patients, doctors, and health professionals helped design the study and analyze the data.

What were the limits of the study?

Results may have been different if researchers had used other ways to categorize clinics into groups that give more versus fewer tests. The team compared patients based on the type of clinic they went to for follow-up tests. But some patients at the clinics that gave more tests might have had fewer tests.

Future research could use a different study design to compare follow-up methods, such as following patients who have more versus fewer tests going forward.

How can people use the results?

Patients who have had colorectal cancer and their doctors can use the results to discuss how often to have follow-up tests.

Final Research Report

View this project's final research report.

Journal Citations

Article Highlight: For patients who have surgery to remove colorectal tumors, reoccurrence of tumors is a major concern. Researchers in this study reported in JAMA that healthcare facilities that do more-frequent surveillance failed to detect recurring cancers any sooner than facilities that do less-frequent surveillance. The study, which analyzed data from more than 8,000 patients, also found no link between the intensity of surveillance and overall survival, suggesting more-frequent surveillance provided no health benefit.

Peer-Review Summary

Peer review of PCORI-funded research helps make sure the report presents complete, balanced, and useful information about the research. It also assesses how the project addressed PCORI’s Methodology Standards. During peer review, experts read a draft report of the research and provide comments about the report. These experts may include a scientist focused on the research topic, a specialist in research methods, a patient or caregiver, and a healthcare professional. These reviewers cannot have conflicts of interest with the study.

The peer reviewers point out where the draft report may need revision. For example, they may suggest ways to improve descriptions of the conduct of the study or to clarify the connection between results and conclusions. Sometimes, awardees revise their draft reports twice or more to address all of the reviewers’ comments. 

Peer reviewers commented, and the researchers made changes or provided responses. The comments and responses included the following:

  • The reviewers asked why the analyses did not connect the intensity of cancer surveillance at the individual patient level directly, rather than at the facility level. The researchers indicated that individual patients’ surveillance intensity typically was related to their risk of recurrence, thus leading to potential bias at the individual patient level.
  • Since the study observed no difference in survival based on surveillance intensity, the reviewers said it would have been interesting to include patients who did not have any surveillance. The researchers said their study excluded patients who received no surveillance because that is not in line with recommended practice and is often associated with patient factors that could bias findings.
  • The reviewers said it would be helpful to see an economic analysis of the difference between high-intensity and low-intensity surveillance facilities since the study implies that the low-intensity facilities provided similar quality of care more efficiently. The researchers said an economic analysis was beyond the scope of this study and would have been difficult to conduct given the lack of identifying information collected about patients. An analysis of costs to operate high- versus low-intensity surveillance facilities would also fall outside of PCORI’s restrictions on funding cost effectiveness research.
  • The reviewers asked the researchers to justify combining colon and rectal cancer outcomes, since these are distinct diseases with different treatments and prognoses. The researchers said that despite the differences between them, the follow-up strategies for the two diseases are the same, and the two surveillance intensity groups had a balanced number of colon and rectal cancer patients.

Conflict of Interest Disclosures

Project Information

George J. Chang, MD, MS
Alliance for Clinical Trials in Oncology Foundation
Patient-Centered, Risk-Stratified Surveillance After Curative Resection of Colorectal Cancer

Key Dates

September 2013
June 2019

Study Registration Information


Has Results
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Health Conditions Health Conditions These are the broad terms we use to categorize our funded research studies; specific diseases or conditions are included within the appropriate larger category. Note: not all of our funded projects focus on a single disease or condition; some touch on multiple diseases or conditions, research methods, or broader health system interventions. Such projects won’t be listed by a primary disease/condition and so won’t appear if you use this filter tool to find them. View Glossary
Populations Populations PCORI is interested in research that seeks to better understand how different clinical and health system options work for different people. These populations are frequently studied in our portfolio or identified as being of interest by our stakeholders. View Glossary
Intervention Strategy Intervention Strategies PCORI funds comparative clinical effectiveness research (CER) studies that compare two or more options or approaches to health care, or that compare different ways of delivering or receiving care. View Glossary
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Last updated: April 12, 2024