November 10th, 2010
02:27 PM ET
Every weekday, a CNNHealth expert doctor answers a viewer question. On Wednesday, it's Dr. Otis Brawley, a chief medical officer for the American Cancer Society.
Question asked by Brian Bauman of Columbus, Ohio:
Are there any treatments for acute myelogenous leukemia?
Acute myelogenous leukemia is a series of diseases involving the white blood cells. These are the cells that fight infection. A number of genetic markers are used to categorize AML into several diseases.
Common to all AMLs is the fact that the bone marrow produces these cells, but they fail to fully mature. Patients commonly have lots of dysfunctional, not fully developed, white cells in their blood. The inability of these white cells to fight infection and the crowding out and decreased production of other blood cells cause complications.
The AMLs are different from other forms of leukemia in the age of the population affected, the standard treatments used and the chances of cure. The median age for patients who develop AML is about 64, meaning half are over the age of 65 years. Some leukemias, such as acute lymphocytic leukemia in children, have very high cure rates.
AML has a much poorer prognosis, especially for older patients. The median survival for patients over 60 is two months. The two-year overall survival is about 6 to 8 percent.
Treatments for AML are harsh. Younger patients tend to tolerate them better. Among AML patients over age 60, treatment is often limited by other co-morbid diseases such as hypertension, diabetes, or kidney or cardiovascular disease. Studies show that nearly a quarter of patients over 60 are not offered aggressive therapy aimed at long-term remission because of concerns about co-morbid disease.
Most published research on aggressively treated older patients with newly diagnosed AML has noted complete remission rates between 40 and 60 percent. This initial therapy is called induction. There are several induction regimens, but the most commonly used include two drugs: daunorubicin and cytarabine. Those who achieve complete remission need to get ongoing maintenance chemotherapy.
The aim of post-remission maintenance therapy is to destroy leukemia cells that survived induction chemotherapy but are undetectable. The preferred therapy for many with AML is stem cell transplant.
Very high doses of chemotherapy are given. The doses are so high that the blood-producing bone marrow is destroyed. Stem cells taken from a donor are then reinfused into the patient. These are cells that are early precursors of bone marrow and reimplant in the patient's bone marrow and start producing blood cells (red cells, white cells and platelets).
Note that some people often confuse stem cell transplants with fetal stem cell therapy. They are not related.
In a small number of patients, a stem cell transplant can be curative, but the therapy can also be fatal, especially in older patients. Consolidation chemotherapy is a less intensive post-remission maintenance therapy than a stem cell transplant. It is more commonly done in elderly patients. It has a lower early mortality rate but is less effective. Approximately 10 percent of AML patients over age 60 are alive five years after diagnosis.
The drug Mylotarg, generic name Gemtuzumab ozogamicin, was FDA-approved for post-remission treatment of AML in patients over age 60 several years ago. After post-approval evaluation, the drug was withdrawn in June 2010 as ineffective.
Participation in a clinical trial aimed at finding a better treatment is always a good option for patients who qualify. It is especially good when the prognosis with standard treatment is poor. Participants are getting a standard treatment or a new treatment that a number of experts have looked at and decided is reasonable.
You can think of this as not a second or third opinion, but a more powerful consensus of a number of experts. It is also of note that studies show that doctors who participate in clinical trials give better, more state-of-the-art therapy to all their patients than doctors who do not participate in clinical trials.
There are two very good sources for finding cancer clinical trials in the U.S. One is sponsored by the American Cancer Society (my employer) and the other by the National Cancer Institute.
The American Cancer Society Clinical Trials Matching Service is a free, confidential program that helps patients, their families and health care workers find cancer clinical trials most appropriate to a patient's medical and personal situation. It can be reached by phone at 1-800-303-5691 or the service's website.
The National Cancer Institute service is accessible at 1-800-4-CANCER or its website.
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