Myelodysplastic Syndromes More Common Than Thought

Roxanne Nelson

April 30, 2010

April 30, 2010 — Myelodysplastic syndromes (MDS) appear to be nearly 5 times more common in older adults than previously thought, according to a new study published online April 26 in the Journal of Clinical Oncology.

MDS patients face a much higher risk for cardiac-related events, diabetes, hepatic diseases, and infections than the general population in the same age group. However, the study found that 3-year survival rates for MDS patients were better, and there were lower transformation rates to acute leukemia than what has previously been reported.

The researchers point out that until 2001, tumor registries were not required to report MDS as a cancer to the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) program.

The SEER database reported that there were approximately 10,300 incident cases diagnosed in the United States in 2003, and an expanded review from the North American Association of Central Cancer Registries (NAACCR) estimated that there were about 9,700 new patients in 2004.

The SEER data also reported a 3-year survival rate of only 35% among MDS patients.

However, lead author Stuart L. Goldberg, MD, chief of the Division of Leukemia at John Theurer Cancer Center, Hackensack University Medical Center, New Jersey, believed that number was too low.

"Based on what we were seeing clinically, 10,000 patients seemed to be a very low estimate," Dr. Goldberg told Medscape Oncology. "We figured that we should be seeing a higher number than that."

Dr. Goldberg explained that many MDS patients are treated by local primary care physicians and hematologists in the office setting, so the information is never sent to tumor registries. "This is a disease that is primarily diagnosed in the office, so hospital registries are going to miss many of these patients," he said. "Only 4% of MDS patients in NAACCR were reported by physicians' offices."

Higher Rates Revealed

Dr. Goldberg and his team hypothesized that a review of Medicare claims would provide more comprehensive information about MDS patients in the United States, because 86% of patients are 60 years or older at diagnosis. The Medicare claims data would capture services provided across specialties and delivery sites, and their analysis would be independent of the biases of pathologically-based cancer registries.

Of 1,394,343 individuals enrolled in the Medicare Standard Analytic Files in 2003, the authors identified 2,253 patients with newly diagnosed MDS, yielding an incidence rate of 162 per 100,000. Compared with the general Medicare population, those with MDS tended to be older (median age, 77 years) and overrepresented by men (P > .001).

When applied to the entire Medicare population in 2003, the authors calculated an MDS incidence of approximately 45,000 cases (compared with the 10,300 cases in 2003 in the SEER database).

There was also a much higher incidence of other serious illnesses in MDS patients than in the general Medicare population. Within 3 years of diagnosis, 73.2% of MDS patients experienced cardiac events, compared with 54.5% of the general Medicare population. The prevalence of other conditions was also higher, including diabetes (40.0% for MDS vs 33.1% non-MDS patients), dyspnea (49.4% vs 28.5%), liver disease (0.8% vs 0.2%), and sepsis (22.5% vs 6.1%).

Increased Comorbidity Among Transfusion Recipients

MDS patients who received blood transfusions had a greater prevalence of these comorbidities. Compared with MDS patients who were not transfused, they had a higher prevalence of cardiac events (82.4% in transfused vs 67.1% in nontransfused patients), diabetes mellitus (44.4% vs 37.1%), dyspnea (62.9% vs 40.4%), hepatic disease (1.0% vs 0.7%), and infectious diseases (81.0% vs 55.7%).

The authors noted that although acute myeloid leukemia developed within 3 years in 9.6% of patients, there was a much higher transformation among those who had received transfusions (24.6%; P < .001).

The 3-year adjusted survival for MDS patients was 60%, which was significantly lower than for the general Medicare population (84.7%; hazard ratio, 3.08; P < .001), and nontransfused patients had a higher 3-year age-adjusted survival rate than transfused patients (69.0% vs 40.9%).

"Our study showed us that not only is this disease more common than previously thought, but now we are able to follow patients for a number of years and obtain longitudinal data," said Dr. Goldberg. "We also found that survival was better than previously reported."

Although the health consequences and scope of the disease were found to be substantial, Dr. Goldberg pointed out that MDS was also costly. In 2003, the median amount billed to Medicare for MDS was $16,181, compared with $1,575 for Medicare beneficiaries in general.

Baseline Provided for Future Research

In addition to an increased understanding of the scope and morbidity of the disease, Dr. Goldberg explained that this study will provide a much needed baseline for additional research. This study was conducted before there was any treatment for MDS, other than transfusions and therapy aimed at relieving symptoms. Since that time, 3 drugs have received approval from the US Food and Drug Administration for the treatment of MDS — 5-azacitidine, decitabine, and lenalidomide.

"The new treatments are very expensive, but if they are effective in changing the biology and course of the disease, they may reduce other expenses related to MDS, such as transfusions," he said. "This was a natural history study, and it will give us a baseline for future studies with patients who are now being treated with the new medications."

Dr. Goldberg has disclosed no relevant financial relationships. Several coauthors report receiving compensation from Novartis, and one reports receiving compensation from Quorum Consulting.

J Clin Oncol. Published online April 26, 2010. Abstract

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