How is Acute Lymphocytic Leukemia Classified?

Most types of cancer are assigned a numbered stage based on the size of the tumor and how far it has spread. But because leukemia already involves all the bone marrow and, in many cases, has also spread to other organs, the outlook for the person with ALL depends on other information such as the subtype of ALL, the age of the patient, and lab test results..

The FAB (French-American-British) Classification

Several years ago, an international conference of doctors who specialize in leukemia was held to decide on the best system for classifying acute leukemia. They decided upon 3 subtypes for ALL based only on the way the leukemia cells looked under the microscope.

More recently, doctors have found that certain advanced chemical tests provide more detailed information about the subtype of ALL and the patient's outlook. These tests help divide ALL into groups based on certain features of the cells and how mature the leukemia cells are. These groups have largely replaced the FAB classification.

Prognostic Factors

As leukemia treatment has improved over the years, research has focused on why some patients have a better chance for cure than others. Certain features of the disease separate patients who are likely to have a good response to treatment from those likely to have a poor response. These are called prognostic factors. These features include the patient's age, white blood cell count, ALL subtype, certain test results, and how they respond to treatment.

While some patients might find detailed information about subtypes and prognostic factors helpful, others may find it a bit overwhelming. The American Cancer Society has detailed information about these subtypes and prognostic factors in a separate document (Leukemia--Acute Lymphocytic).