November 5, 2020, 12:11 pm Michael Devitt -- On Oct. 27, the U.S. Preventive Services Task Force posted a draft recommendation statement, draft evidence review and draft modeling report on screening for colorectal cancer in adults.
Based on its review of the available evidence, the task force recommended
The draft recommendations apply to adults who do not have symptoms or a personal history of colorectal polyps, or a personal or family history of genetic disorders that increase CRC risk.
“Unfortunately, not enough people in the United States receive this effective preventive service that has been proven to save lives,” Alex Krist, M.D., M.P.H., a professor in the Department of Family Medicine and Population Health at Virginia Commonwealth University School of Medicine in Richmond and the task force’s chair, said in a press release. “We hope that this recommendation to screen people ages 45 to 75 for colorectal cancer will encourage more screening and reduce people’s risk of dying from this disease.”
Excluding some types of skin cancer, CRC is the third-most common cancer and the third leading cause of cancer-related deaths in the United States. While the overall rate of people being diagnosed with colon or rectal cancer has decreased since the mid-1980s, the American Cancer Society estimates that more than 147,000 new cases of colon or rectal cancer will be diagnosed in the United States this year.
When final, the recommendation will replace the task force’s 2016 recommendation statement on the topic.
The 2016 recommendation statement gave an “A” recommendation designation to screening for CRC for adults 50 to 75. The 2016 recommendation statement also said that for adults 76 to 85, the decision to screen should be an individual one that takes the patient’s overall health and prior screening history into account – a “C” recommendation designation.
The AAFP issued a different recommendation in 2016, giving a “B” recommendation designation for CRC screening in adults 50 to 75 and acknowledging the variation of risks and benefits among screening modalities. In addition, the AAFP recommended individualized shared decision-making for adults 76 to 85, a “C” recommendation aligning with that of the USPSTF. The AAFP also recommended against screening in adults older than 85. In its clinical considerations, the AAFP also highlighted key differences in screening modalities and called out areas of insufficient data on harms for some of the newer tests.
To update the 2016 recommendation, the USPSTF commissioned a systematic evidence review to evaluate the benefits and harms of screening for CRC in adults 40 and older, with a focus on the effectiveness and comparative effectiveness of screening strategies, and the accuracy of and serious harms associated with different screening tests. The review included more than 200 studies, 70 of which were new since the prior evidence review.
In addition, the task force commissioned a comparative modeling report from the Cancer Intervention and Surveillance Modeling Network’s Colorectal Cancer Working Group to provide information on how estimated life-years gained, cases averted and deaths from CRC averted vary based on different starting and stopping ages for various screening strategies.
Based on the evidence review, the task force recommended two types of tests to screen for CRC:
The task force noted that these tests have different evidence levels to support their use, and different performance levels in cancer detection and different risks of harms and said that comparative studies cannot answer questions on the tests' relative benefits and harms.
“There are many tests available that can effectively screen for colorectal cancer,” explained task force member Martha Kubik, Ph.D., R.N. “We urge primary care clinicians to discuss the pros and cons of the various recommended options with their patients to help decide which test is best for each person.”
The task force added that its recommendation does not include serum tests, urine tests or capsule endoscopy as appropriate modalities for CRC screening because of a lack of available evidence.
Perhaps the most notable change from the 2016 recommendation statement is the decrease in the starting age for CRC screening from 50 to 45 years.
“Although the absolute risk of developing colorectal cancer is much lower in adults younger than age 50 years … age period-cohort analysis indicates a recent trend for increasing colorectal cancer in adults younger than age 50 years,” the task force wrote in the Practice Considerations section of the recommendation summary.
“Additionally, modeling performed by CISNET suggests that starting colorectal cancer screening at age 45 years can moderately increase life-years gained and decrease colorectal cancer cases and deaths compared to beginning screening at age 50 years,” the task force continued.
In its evidence review, the task force also stated that increasing age, male sex and being Black were associated with an increased incidence of CRC, and that overall, Black men and women had the highest incidence of CRC compared with other population subgroups. As such, the USPSTF encouraged clinicians to offer screening to Black patients beginning at age 45.
“New science about colorectal cancer in younger people has enabled us to expand our recommendation to screen all adults starting at age 45, especially Black adults who are more likely to die from this disease,” said task force member Michael Barry, M.D. “Screening earlier will help prevent more people from dying from colorectal cancer.”
Sarah Coles, M.D., of Phoenix, who chairs the Subcommittee on Clinical Recommendations and Policies for the Academy’s Commission on Health of the Public and Science, told AAFP News it’s important to remember that the new recommendation statement is a draft that is still subject to change.
If the recommendation remains in its current state, however, it could have considerable ramifications for FPs and their patients.
“Should the USPSTF finalize this recommendation, family physicians may begin offering colorectal cancer screening to average-risk individuals starting at age 45, and as a ‘B’ grade recommendation for ages 45 to 49, this will be covered by insurance under the (Patient Protection and) Affordable Care Act,” Coles said.
“This has the potential to both increase access to screening and reduce disparities, but there remain potential harms as well,” Coles continued. “The USPSTF used modeling data to estimate the benefit in this younger population. This model assumes that screening will be as effective in younger folks, which is not yet supported by clinical trial data of screening programs. It is also possible the access to colonoscopy, both as the primary screening modality and as the diagnostic test following abnormal stool-based screening, may be overwhelmed depending on community resources. Family physicians should be aware of their community needs and resource allocation.”
Coles said that in her practice, she primarily uses stool-based tests and colonoscopy to screen for CRC. When discussing the benefits and harms of screening with patients, she said the discussions must include potential next steps in case a patient has a positive screening test.
The new recommendation, if finalized in its present state, would give FPs additional factors to consider when discussing CRC screening with some patients.
“For individuals younger than the age of 50, it would be important to discuss potential benefits, risk of harms and what is still unknown,” said Coles. “The USPSTF model suggests that starting at age 45, one to two additional deaths from colorectal cancer for every 1,000 people screened would be avoided, but that many more would require colonoscopy and a minority would have a complication from the colonoscopy. It would also be important to discuss that the benefits and risks are derived from models, and that the true benefits and risks are not yet known in this population.”
Consideration of other factors must also be weighed when discussing screening for CRC in Black patients.
“It is critical to remember that race is a sociopolitical construct and does not reflect shared genetic ancestry,” Cole said. “Disparities exist due to systemic racism and policies that drive inequities in social determinants of health. As family physicians, we should be aware of these disparities and understand that they do not reflect biological differences, but rather are the result of racist systems, and work to address racism and bias in our practices, health care systems and communities. This recommendation is a call to action to address disparities in access to screening and subsequent treatment.”
Finally, Coles emphasized the importance of appropriate follow-up with patients who have abnormal test results.
“Screening for colorectal cancer is an important part of preventive health care,” Coles said. “We know, unfortunately, that many abnormal screening tests do not get the appropriate followup testing. It is important that abnormal screening tests receive followup care in order for the benefits of screening to be seen. A population health approach, with use of registries, can help ensure that eligible populations are offered screening and that abnormal results are followed up.”
The USPSTF is accepting comments on the draft recommendation statement, draft evidence review and draft modeling report on screening for CRC until 11:59 p.m. ET on Nov. 23. All comments received will be considered as the task force prepares its final recommendation.
The AAFP will review the USPSTF’s draft recommendation statement and supporting evidence and will provide comments to the task force. The Academy will release its own recommendations on the topic after the task force finalizes its guidance.