By Will Boggs MD
NEW YORK (Reuters Health) - 5/4/2019
Colorectal cancer (CRC) screening beginning at age 45 years instead of 50 years for average-risk individuals is likely cost-effective, researchers report.
"It is reasonable to begin colorectal cancer screening at age 45 based on both expected clinical benefit and economic cost, but this should be done in parallel with attempting to increase screening participation rates in older persons and fecal immunochemical test (FIT)-positive follow-up rates, because the yield from these is predicted to be much greater," Dr. Uri Ladabaum from Stanford University School of Medicine in California told Reuters Health by email.
In response to the rising incidence of CRC in younger people, the American Cancer Society recommends initiating average-risk CRC screening at age 45 years. In contrast, the U.S. Preventive Services Task Force (USPSTF) and the U.S. Multi-Society Taskforce recommend screening beginning at age 50 years.
Dr. Ladabaum and colleagues used a decision analytic model to estimate the cost-effectiveness and national impact of beginning CRC screening at age 45 instead of 50 and to contrast the effect of allocating screening resources to younger versus older and higher-risk persons.
In the model, screening colonoscopy initiation at age 45 instead of age 50 averted four CRCs and two CRC deaths and gained 14.4 quality-adjusted life-years (QALYs) per 1,000 persons, while requiring 758 additional colonoscopies and costing $33,900/QALY gained.
FIT initiation at age 45 instead of 50 averted four CRCs and one CRC death and gained 14.0 QALYs per 1,000 persons; it required 267 additional colonoscopies and 3,242 additional stool tests, for a cost of $7,700/QALY gained, the researchers report in Gastroenterology, online March 28.
Two other scenarios (one-time sigmoidoscopy at age 45 followed by colonoscopy or FIT screening starting at age 50; annual FIT at ages 45-49 with transition to colonoscopy every 10 years at age 50) achieved nearly the same clinical benefits at different costs . The additional 758 colonoscopies required to screen 1,000 persons beginning at age 45 instead of 50 could, alternatively, be used to initiate and sustain screening through age 75 in 231 currently unscreened 55-year-olds or 342 currently unscreened 65-year-olds, yielding substantially greater clinical benefits: 13-14 CRCs averted, six-seven CRC deaths averted, and 27-28 QALYs gained.
These alternative allocations would result in net savings of $163,700-$445,800, the researchers estimate.
At the national level, shifting current screening participation patterns by five years to younger ages could avert 29,400 CRC cases and 11,100 CRC deaths over the next five years, but at an incremental cost of $10.4 billion and requiring 10.7 million additional colonoscopies.
On the other hand, achieving the goal of 80% screening participation beginning at age 50 (without lowering the screening age to 45) could avert 2.6-fold more CRC cases and 2.9-fold more CRC deaths at approximately one-third the incremental cost and with the need for 13% more additional colonoscopies.
"Advocates for either approach can find some support in our findings," Dr. Ladabaum said. "It comes down to whether, as a society, we can do both: that is, start screening earlier and at the same time improve participation in the older and higher risk groups."
"At a systems level, I think we should either focus on improving screening rates in older people instead of shifting any resources (outreach or services) to starting screening in younger people, or on addressing both simultaneously if the system can expand appropriately to support that," he said.
"At the individual practice level, if motivated patients wish to have screening at age 45-49, I think that is perfectly reasonable. Not all lack of screening at older ages reflects system failures or lack of access. From this perspective, the fact that a 63-year-old person may have chosen not to screen for the last 13 years should not automatically disqualify an interested 45-year-old from pursuing screening," he added.
Dr. Benjamin A. Weinberg from Georgetown University Medical Center's Lombardi Comprehensive Cancer Center, in Washington, D.C., who recently reviewed trends in colon cancer in young adults, told Reuters Health by email, "We have to develop smarter, adaptive screening strategies. For patients with normal risk, an age cutoff is simple but likely too simplistic."
"Our research at Georgetown delves into whether bacteria within the colorectal tumors of young vs. older individuals are different," said Dr. Weinberg, who was not involved in the new study. "In the future, it may be possible to assess for a high-risk stool-microbiome composition to better delineate who should get colonoscopies at 50 and who should get colonoscopies at 45 (or perhaps even earlier). These risk-adaptive screening methodologies will enable us to be smarter when it comes to who needs to be screened, when, and how often."
Dr. Weinberg said, "Once we offer colonoscopies at age 45, it will be hard to rescind this recommendation (see mammographic screening for breast cancer) - we are perpetually putting out onto social media recommendations to be screened early and often, but many screening tests are not cost-effective nor recommended by more conservative groups such as the USPSTF. There is a visceral reaction to want to find cancers in younger people who historically were spared this disease, and the advocacy groups are in strong favor of the age 45 recommendation."
"A large randomized trial where normal-risk patients are followed at age 45 and are randomized to get colonoscopies at age 45 vs. 50 (or potentially a third arm with annual FIT testing for ages 45-50) would help answer these questions; it is unclear if such a trial will ever take place, due to costs, etc.," he added.
Dr. Elena M. Stoffel of the University of Michigan's Rogel Cancer Center, in Ann Arbor, recently reviewed the changing epidemiology of CRC. She told Reuters Health by email, "The rising incidence of CRC in young individuals stresses the importance of implementing CRC risk assessment for all patients regardless of age. A significant proportion of early-onset CRC deaths could be averted if clinicians investigated red-flag symptoms in a timely manner and systematically elicited family cancer history."
"One in 5 young CRC patients have a heritable genetic factor associated with increased risk for cancer," said Dr. Stoffel, who also was not involved in the study. "Instead of screening everyone at 45, a more effective (and cost-effective) approach would evaluate each patient's risk - some will require colonoscopy earlier than age 45, while others may need only non-invasive screening at 50 or later."