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May 18, 2004 DAY #203
Leukemia Statistics and Survival Rates
Of the estimated 31,000 new cases of Leukemia in the United States this year, about half will be chronic and half will be acute. Leukemia strikes about 8 times as many adults as children. Estimates for this year are 27,800 adults and 3,400 children (ages 0 to 19), with over half of the new cases found after age 64. The most common form of Leukemia in children is ALL, representing about 85 percent of childhood Leukemia. The most common form of adult Leukemia is AML. About 5000 cases of Leukemia this year will be unclassified or rare forms not included in the four mentioned above.
Survival rates have climbed steadily since the late 1950s, when 5 year survival rates were pretty uniformly 0%. During 1992-1999, 5 year survival rates overall were:
- ALL: 63.5 percent overall; 85 percent for children
- CLL: 73.5 percent
- AML: 18.7 percent; 46 percent for children
- CML: 34.9 percent
In a recent study of AML, released May 14, 2004, the 5 year survival rate was about 23%. Significant improvements in long term survival rates have been the result of research supported by contributions to organizations such as the American Cancer Society and the Leukemia and Lymphoma Society.
AMLs are of particular interest to me, as that is the form of Leukemia I had. AMLs are differentiated into 8 types by the French-American-British (FAB) Group. The types are numbered from M0 to M7. Survival rates from M0, M5, M6, and M7 are worse than average. Survival rates for M2, M3, and M4 are better than average. Survival rates for M1 are about average. Survival rates are also impacted by several other factors, including patient age, physical condition, attitude and support. The highest rates of long term survival (about 60%) for most forms of AML are achieved through a matched, related stem cell transplant. Matched unrelated transplants and transplants of the patientís own stem cells result in about a 50% long term survival rate. Treatment with Chemotherapy only typically results in the poorest survival rates. My diagnosis was M0, but I had a Matched, Related Donor, and have survived the procedure without serious problems so far. This puts me in the 60% category, and I probably have some additional advantages because of my age.
ALLs are classified by FAB into three general types, L1, L2, and L3. L1 is most frequently seen in children (75%), L2 is the most common form of adult ALL (70%). L3 is rare. Long term survival rates for L1 are significantly better than that of L2 and L3.
There are many different types of CLL, but they are generally characterized by stages. There are a couple of different ways to indicate stages. The staging system most commonly used in the US is the RAI system. Stage 0 has no symptoms, and long term survival of 15 years is expected. Stage 1 and 2 may have symptoms. If no symptoms are present, survival of up to 7 years without treatment is normal. If symptoms are present, chemotherapy or radiation treatments are indicated. Stage3 and higher forms are considered high risk. Survival times of about 4 years are normal. CLL rarely becomes an Acute Leukemia.
CML is characterized by three phases:
- The chronic phase
- The accelerated phase
- The blast phase
In the chronic or stable phase, symptoms are mild and vague. They may include tiredness, loss of weight and an enlarged spleen. The white cell count and platelet counts may be elevated. About 9 out of 10 (90%) people diagnosed with CML are in chronic phase. In the accelerated phase, symptoms become more obvious. Weight loss and fatigue are more pronounced. Enlargement of the spleen can cause discomfort or pain on the left side of the abdomen under the ribs. In the blast phase CML becomes more aggressive. Symptoms are quite troublesome and patients feel quite ill. CML can often lead to AML in later stages of the disease. Fortunately, there is a new drug, Gleevec, that is very effective at controlling CML.
Long term survival for all types of Leukemia is enhanced by early detection. If you have symptoms described above, you should notify your doctor immediately!
The causes of Leukemia are unknown. In some cases, it seems to be related to exposure to benzene or very high doses of radiation. Smoking is clearly implicated as a risk factor for some types of Leukemia. There is some recent evidence that stress may be a factor in some types. Many types of Leukemia are accompanied by chromosomal abnormalities. CLL L2 may have a genetic risk factor, but most Leukemia does not seem to be genetic in nature. Treatments have been developed for several types of Leukemia, but much more work needs to be done. Research is needed to identify the causes, and the biological pathways leading to each subtype of Leukemia. There are several other types of blood cancers including Lymphomas, and Myelomas. More research is required to identify cures for each of these cancers also.
Coming tomorrow, The Costs of Leukemia!
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