Myelodysplastic syndromes (MDS) are nearly five times more common in older people than had been previously thought, according to a study by researchers from the John Theurer Cancer Center at Hackensack University Medical Center in New Jersey.
The study also showed for the first time that MDS patients are at much higher risk for heart attack, diabetes, and other serious complications than other older people are and that their health care costs are far higher. The study is published online in the Journal of Clinical Oncology.
“This study demonstrates that MDS is a very common blood cancer of the elderly, and that those who have it are at high risk of dying prematurely from other causes,” lead author Stuart L. Goldberg, MD, Chief of the Division of Leukemia, said in a news release. “This has implications for how the disease is treated and will hopefully spur additional research.”
MDS was not reportable as a cancer until 2001, when the NCI began requiring that all tumor registries report cases to the SEER program. The SEER database reported 10,300 newly diagnosed MDS patients in 2003, with a three-year survival rate of just 35%.
To conduct a “head-to-head” study, Dr. Goldberg and colleagues analyzed claims data for Medicare beneficiaries age 65+ for 2003. They found an estimated 45,000 new cases of MDS.
The gap in estimates can be explained by differing data sources, the researchers said: Medicare data are submitted by both physicians in private practice as well as hospital-based physicians, while SEER data come strictly from tumor registries, which are primarily found in hospitals.
“MDS is generally treated by hematologists and primary care physicians in private practice, and elderly patients with MDS are frequently not seen at a hospital-based cancer center until their disease progresses, so most cases are not being reported to NCI,” Dr. Goldberg said. “As we found in our study, many apparently die of other causes as their disease progresses.”
The researchers found a much higher incidence of other serious illnesses among MDS patients than among American elderly people as a whole. More than 73% of MDS patients experienced a heart attack within three years of diagnosis, vs 54.5% of the general Medicare population.
The prevalence of other conditions was also higher, including: diabetes (40% for MDS patients, vs 33% non-MDS); dyspnea (49% vs 28.5%); liver disease (0.8% vs 0.2%); and sepsis (22.5% vs 6%). MDS patients requiring blood transfusions had a higher incidence of these conditions than those who were not transfused.
Acute myeloid leukemia (AML) developed within three years in almost 10% of newly diagnosed MDS patients, and those who received transfusions progressed to AML at a rate of nearly 25% (previous estimates were that about 20% to 30% of MDS patients progressed to AML).
A much higher percentage of MDS patients died during the study period than those without MDS. The three-year survival rate for those with MDS was 60% vs about 85% for the general Medicare population.
The mortality rate for transfused MDS patients was higher than for those not transfused. The higher survival rates in this study compared with SEER were attributed to the higher percentage of early-stage patients treated in communities compared with hospital-based tumor registries.
Dr. Goldberg and his colleagues said that while the health consequences and scope of the disease found in the study were alarming, the cost of treating MDS also proved to be significant: In 2003, the median amount billed to Medicare for MDS was $16,181, compared with $1,575 for Medicare beneficiaries as a whole.
“As the US population continues to age, MDS will become a more prominent medical problem with a significant impact on the health care system,” he said.