More patients diagnosed at earlier stage of colon cancer since expansion of screening coverage

Since Medicare raised the amount it will reimburse for colon cancer screening in 1998, there has been an increase in use of colonoscopies by Medicare beneficiaries, and a rise in the proportion of patients being diagnosed with colon cancer at an early stage, according to a study in the December 20 issue of JAMA.

Although regular screening is the most effective way to detect colon cancer at an early, curable stage, widespread screening has been below optimal levels, according to background information in the article. The 2000 National Health Interview Survey found that 42.5 percent of respondents 50 years of age and older were up to date with colon cancer screening with any of the recommended methods; among persons 65 years of age and older, 48.7 percent were up to date. Several studies have suggested that lack of insurance coverage may be one of the most important barriers to colon cancer screening. Prior to 1998, Medicare did not routinely reimburse for colon cancer screening.

Cary P. Gross, M.D., and colleagues from the Yale University School of Medicine, New Haven, Conn., evaluated whether the implementation of the expanded Medicare reimbursement policies after 1998 was associated with changes in the use of colonoscopy among Medicare beneficiaries without cancer, as well as changes in the proportion of colon cancer patients who were diagnosed at an early stage. The researchers analyzed data from the Surveillance Epidemiology and End Results (SEER) -Medicare linked database of individuals who were 67 years of age and older and had a primary diagnosis of colon cancer during 1992-2002, as well as a group of Medicare beneficiaries who were not diagnosed with cancer. Among the patients with cancer, stage was classified as early (stage I) vs. all other (stages II-IV). Time was categorized as period 1 (no screening coverage, 1992-1997), period 2 (limited coverage, January 1998-June 2001), and period 3 (universal coverage, July 2001-December 2002).

The researchers found that among the sample of Medicare beneficiaries who did not have cancer, there was an increase in colonoscopy use during the study period. The average colonoscopy rate per 100,000 beneficiaries per quarter tripled from period 1 to 2, and went up 6.5 times, comparing period 1 to period 3.

The final sample of patients with colorectal cancer consisted of 44,924 patients (average age, 77.4 years; 56 percent were women and 8 percent were black). Time period was significantly related to stage at diagnosis. Approximately 22.5 percent of patients were diagnosed at an early stage in period 1 (1992-1997) compared with 25.5 percent in period 2 and 26.3 percent in period 3. In further analysis, patients diagnosed in periods 2 and 3 were significantly more likely to have early-stage illness than patients diagnosed in period 1.

"Our finding that new Medicare policies may have facilitated early diagnosis is encouraging and supports the institution and evaluation of other efforts to broaden the access to and use of screening tests in the older population. Given that there are approximately 60,000 cases of colorectal cancer diagnosed annually among patients 65 years of age and older in the United States, even a 4 percent increase in the percentage of patients whose cancer is diagnosed at an early stage can have a substantial impact at the population level," the authors write. "Increasing the use of screening tests further has the potential to diagnose many more beneficiaries at an early stage."

(JAMA. 2006;296:2815-2822. Available pre-embargo to the media at www.jamamedia.org)

Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

In an accompanying editorial, Arden M. Morris, M.D., M.P.H., of the University of Michigan, Ann Arbor comments on the study by Gross and colleagues.

"The findings of Gross et al demonstrate that the change in Medicare policy was effective: a target population received screening at a higher rate and this resulted in an increase in the detection of early stage and right-sided cancers. It remains to be seen if future screening will continue to increase the rates of early identification of colorectal cancer. Given the costs of universal screening, if rates of colonoscopy continue to increase without additional benefit in overall diagnosis of early stage disease, policy makers, health care organizations, and physicians may have to devise a feasible rationing plan for broader colon screening. While increasing access to care and improving compliance with recommended care is an undeniable good, providing screening colonoscopy to all is not realistic.

"The onus is on physicians and other primary care clinicians to capitalize on the momentum associated with screening colonoscopy to encourage other effective but less expensive forms of screening, such as fecal occult blood tests with sigmoidoscopy. Screening colonoscopy could be made more effective by targeting subgroups with higher incidence and mortality from colorectal cancer, and those at greatest risk of right-sided or proximal neoplasms that would not be identified by sigmoidoscopy. Such a strategy, while difficult, would provide the best opportunity to judiciously maximize access to care without sacrificing outcomes," Dr. Morris writes.

(JAMA. 2006;296:2855-2856. Available pre-embargo to the media at www.jamamedia.org)

Editor's Note: Dr. Morris is supported by a Mentored Research Scholar Grant from the American Cancer Society. Financial disclosures: none reported.

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