FRIDAY, Nov. 12 (HealthDay News) -- Patients with a certain type of leukemia who had insufficient vitamin D levels when their cancer was diagnosed saw their disease progress much faster and were two times more likely to die than those with adequate vitamin D levels, a new study finds.
Researchers also discovered that increasing vitamin D levels in patients was linked to longer survival times, even after controlling for other factors associated with leukemia progression.
This is an important finding for both patients and doctors, according to the researchers at the Mayo Clinic in Rochester, Minn. and the University of Iowa.
The disease -- chronic lymphocytic leukemia (CLL) -- is cancer of the white blood cells (lymphocytes) and mainly affects adults. Although CLL is often diagnosed at an early stage, the standard approach is to wait until patients develop symptoms before beginning chemotherapy, explained study author and hematologist Dr. Tait Shanafelt.
"This watch-and-wait approach is difficult for patients because they feel there is nothing they can do to help themselves," Shanafelt said in a Mayo news release. "It appears vitamin D levels may be a modifiable risk factor for leukemia progression. It is simple for patients to have their vitamin D levels checked by their physicians with a blood test. And if they are deficient, vitamin D supplements are widely available and have minimal side effects."
This study of 390 CLL patients found that 30 percent of them had insufficient vitamin D levels (less than 25 nanograms per milliliter) at the time of cancer diagnosis. After a median follow-up of three years, patients with insufficient vitamin D levels were 66 percent more likely to have disease progression and to require chemotherapy. They also had a twofold increased risk of death, compared to those with adequate vitamin D levels.
Similar findings were seen in a different group of CLL patients who were followed for 10 years, according to the researchers.
"This tells us that vitamin D insufficiency may be the first potentially modifiable risk factor associated with prognosis in newly diagnosed CLL," Shanafelt said.
The researchers are planning another study to see if reversing low vitamin D levels in patients will improve their prognosis.
The study appears online in the journal Blood.
The Leukemia and Lymphoma Society has more about chronic lymphocytic leukemia.
-- Robert Preidt
SOURCE: Mayo Clinic, news release, Nov. 4, 2010
All rights reserved