Since Medicare approved coverage for screening colonoscopies, there has been
- a significant increase in the rate of colonoscopies in the Medicare population
- an increased possibility of being diagnosed with colorectal cancer at an early, highly curable stage I
Medicare began to provide reimbursement for people at high risk of colorectal cancer in 1998 and expanded coverage to everyone on Medicare in July of 2001.
Researchers at the Yale University School of Medicine reviewed SEER (Surveillance, Epidemiology, and End Results) information for patients diagnosed with colon cancer between 1992 and 2002. They also looked at a group of Medicare-eligible patients in the database who did not have colon cancer. They examined rates of colonoscopy screening and stage at diagnosis for three periods of time:
- Period 1 – no coverage (1992 to 1997)
- Period 2 — limited coverage (January 1998 – June 2001)
- Period 3 — full coverage (July 2001 – December 2002)
They found increasing rates of colonoscopy screening for people eligible for Medicare. Rates tripled between the period when there was no coverage and doubled again when reimbursement was extended to all patients.
- Period 1 — 285 colonoscopies/100,000 eligible people
- Period 2 – 889/100,000
- Period 3 — 1919/100,000
Separating people diagnosed with colon cancer into two groups: early stage (stage 1) and all other stages (stages II-IV), they found an increasing percentage of patients diagnosed at an early stage.
- Period 1 — 22.5% of cancers were found at an early stage
- Period 2 — 25.5%
- Period 3 — 26.3%
The strongest association with early diagnosis was found in patients whose cancers were in the proximal colon (the first section of colon farthest from the rectum). There was a very small association for distal tumors on the left side of the body.
Dr. Cary Gross and colleagues reported their results in the December 20, 2006 issue of the Journal of the American Medical Association. They concluded,
Expansion of Medicare reimbursement to cover colon cancer screening was associated with an increased use of colonoscopy for Medicare beneficiaries, and for those who were diagnosed with colon cancer, an increased probability of being diagnosed at an early stage. The selective effect of the coverage change on proximal colon lesions suggests that increased use of whole-colon screening modalities such as colonoscopy may have played a pivotal role.
Gross et. al. JAMA. 2006;296:2815-2822
The Centers for Disease Control (CDC) has a fact sheet on colorectal cancer screening for people receiving Medicare.