Advances in treatment options have made leukemia – an umbrella term for a number of blood cell cancers – much more treatable than it once was.
One of the major types of leukemia is chronic myelogenous leukemia (CML), a cancer of the white blood cells. Frederick Weeks, M.D., is an internist and oncology specialist in Vero Beach; he says, “CML used to be universally fatal. We now see a large percentage of patients whose leukemia goes into complete remission. It is one of the great success stories in our fight against cancer.”
CML originates in the bone marrow, a spongy tissue inside larger bones where blood cells are made. It’s caused by a gene mutation that produces an altered chromosome called the Philadelphia chromosome. This mutation occurs without clearly identified risk factors, and it’s not hereditary – it can’t be passed from parent to child. If CML is suspected, blood tests or bone marrow tests are performed to look for the presence of the Philadelphia chromosome.
In the past 15 years or so, CML has been increasingly treated by oral medications called Tyrosine-Kinase Inhibitors (TKIs). TKIs are “targeted treatments”; they focus on specific cell mechanisms thought to be important for cancer growth, and by doing so block the signals that tell cancer cells to grow and divide. Because of this narrow chemical focus, targeted treatments tend to spare healthy cells and cause less severe side effects than chemotherapy.
As with other types of leukemia, the symptoms of CML are often not very specific: feeling run down or tired, night sweats, loss of appetite or bleeding easily. The spleen may also become enlarged, because it is working overtime to remove and destroy abnormal blood cells.
“Some of the signs and symptoms are things all of us have, especially as we get older,” says Dr. Weeks. “But if someone has relentless fatigue, or lots of nosebleeds all of a sudden, they should seek medical care. There could be many causes, and it’s good to get checked out.”
Leukemia begins when normal blood cells change and grow uncontrollably. There are different types of blood cells: red, which carry oxygen throughout the body; white, which fight infection; and platelets that help the blood to clot.
The disease is classified, in part, based on its speed of progression:
• In acute leukemia, the abnormal blood cells don’t carry out their normal functions and they multiply quickly, leading to a rapid worsening of the disease. Acute leukemia requires aggressive, timely treatment. Dr. Weeks says he refers these cases to a center that has experience in evaluating and treating this form of the disease, such as the H. Lee Moffitt Cancer Center & Research Institute in Tampa.
• Chronic leukemia, which comes in many forms, develops more slowly, often doesn’t have symptoms in its early stages, and may go undiagnosed for years.
The exact causes of leukemia are unknown; however, it seems to develop from a combination of genetic and environmental factors, including previous cancer treatment, smoking, family history, exposure to certain chemicals (benzene, a chemical found in gasoline, is one example) and certain genetic disorders. Dr. Weeks says it’s known that past exposure to radiation is a risk factor.
In addition to targeted therapy, treatment approaches to combat leukemia include chemotherapy, radiation, and immunotherapy, which helps the immune system recognize and attack leukemia cells. Some patients will need a stem cell transplant, a procedure to replace diseased bone marrow with healthy marrow. Patients must be in remission before undergoing this procedure. A person’s own stem cells can sometimes be used; in other cases, donor cells will be used.
There was a recent pilot study from the University of Virginia Cancer Center about a treatment approach that combined immunotherapy and targeted therapy. The subject of the study was T-cell prolymphocytic leukemia (T-PLL), a very rare but aggressive form of the disease, mostly diagnosed in older men. It affects a person’s T-cells, a type of white blood cell that helps the immune system fight infection.
The results of the study showed that this combined-treatment approach can send the disease into remission, allowing the patient more time to have a possibly live-saving stem cell transplant. This wouldn’t be of much general interest in and of itself, due the extremely low incidence of T-PLL, but the researchers believe the approach may hold promise for treating other forms of leukemia, as well as many other cancers.
Dr.Weeks’ office is located at 1460 36th St in Vero Beach; his office phone is 772-562-7777.