Understanding Chronic Myelogenous Leukemia (CML)
Three-time Tour de France champion Greg LeMond recently announced he has been diagnosed with a treatable form of cancer, chronic myelogenous leukemia (CML).
In a statement posted to his personal website, LeMond said the illness is not life-threatening but has resulted in bouts of fatigue that ultimately prevented him from attending this year’s Tour de France in person.
According to Moffitt Cancer Center hematologist Dr. Kendra Sweet, chronic myelogenous leukemia is a cancer of the bone marrow that overproduces abnormal white blood cells.
“Essentially this is a change between two chromosomes,” Sweet said. “Part of chromosome 9 and part of chromosome 22 break and swap, which forms the Philadelphia chromosome that defines CML.”
That swap, as Sweet calls it, forms a new gene called BCR-ABL, which shuts off the body’s ability to stop producing abnormal white blood cells. Patients with chronic myelogenous leukemia often have a white blood cell count as high as 50,000 and 300,000 at diagnosis. A healthy patient’s white blood count is somewhere between 4,000 and 11,000, she said.
“Like its name says, this is a chronic disease and does not progress quickly,” Sweet said. “If it goes untreated it can take years to progress and the life span of someone with CML is five to 10 years. Fortunately, we have excellent drugs to treat this and people are able to live much longer, with a life expectancy that is the same as the general population.”
Chronic myelogenous leukemia presents in three progressive phases, chronic, accelerated and blast, which is essentially acute leukemia.
Sweet said that 95% of patients with chronic myelogenous leukemia can control their disease as long as they continue treatment with a daily oral pill. Patients will be monitored throughout their lives to make sure that their white blood cell count stays within the normal range.
“Everything changed for CML in 2001 with the first drug to inhibit BCR-ABL called Imatinib,” she said. “Suddenly we had people living longer with this disease. But there are side effects, including nausea, bone pain and fatigue.”
It’s the hope that one day in the not too distant future, chronic myelogenous leukemia can be cured rather than just treated and there is a consortium working toward that goal of which Moffitt is a part.
LeMond, 60, shared that he sought treatment after feeling poorly, and Sweet added that symptoms of chronic myelogenous leukemia range from fatigue to sudden weight loss and drenching night sweats.
“Another symptom is abdominal pain and loss of appetite because CML can cause your spleen to enlarge,” Sweet said. “The spleen can start abnormally producing cells and become very large and painful.”
Fortunately, chronic myelogenous leukemia is rare and there are only about 5,000 diagnoses of the disease in the U.S. each year. There has been progress, but it’s still unknown what causes this form of leukemia or what triggers the chromosomes to swap and begin creating too many white blood cells.
While LeMond will missed this year’s Tour de France, he is optimistic that he’ll be able to return in the future.
“No one ever wants to hear the word cancer but, admittedly, there is great relief, now, to know why I was feeling poorly,” wrote LeMond, 60. “My doctors and I have decided on a treatment which will begin this week. I should be feeling better in a few weeks and for the near future, my daily schedule will be altered only a little and I have been told that in a few months, I should be in remission.”
The most decorated American male cyclist in history, LeMond won his first Tour de France in 1986, then posted back-to-back titles in 1989 and 1990.
Since retiring from competition in 1994, LeMond has been a staunch anti-doping advocate and is recognized as the only American Tour de France champion — after Lance Armstrong and Floyd Landis were stripped of their titles for doping offenses.
Chronic myeloid leukemia is treated according to its phase (chronic, accelerated or blast) as well as the patient’s age, overall health and other individual factors. Unlike other types of leukemia, however, CML can transform into a more rapidly spreading, acute cancer over time and it often doesn’t produce noticeable symptoms in its early stages. In fact, many patients don’t realize there is a problem until they have routine bloodwork performed. At Moffitt Cancer Center, we offer a complete range of diagnostic tools and treatment techniques for chronic myeloid leukemia and are the only institution in the Southeast of US who has specialized Hematologists that treat CML/CLL.
If you’d like to refer a patient to Moffitt, complete our online form or contact a physician liaison for assistance. As part of our efforts to shorten referral times as much as possible, online referrals are typically responded to within 24 - 48 hours.