Observations made in the study of the leukemias have contributed to our understanding of malignancy in general and to our ability to treat cancer patients with drugs. Although our ability to benefit patients with leukemia has improved dramatically, many problems still remain.
The World Health Organization (WHO) classification of myeloid and lymphoid leukemias includes almost 50 subtypes—a far cry from the 4 subtypes (ie, acute myeloid leukemia [AML], chronic myeloid leukemia [CML], acute lymphoblastic leukemia [ALL], and chronic lymphocytic leukemia [CLL]) that I studied in medical school 42 years ago. The ability to recognize specific subtypes of leukemia based on molecular characteristics offers the opportunity to develop specific and, it is hoped, more effective treatments. However, it also greatly complicates clinical research in a group of diseases that, while not rare, are not so common as to allow the easy performance of comparative trials in small subgroups.
This six-part series, which begins this month and will run through the end of the year, will focus on the clinical problems posed by subtypes of leukemia that confront all oncologists and hematologists who care for patients with these disorders. The articles will include the following topics and authors:
1. Drs. Martin Tallman and Eytan Stein of Memorial Sloan-Kettering Cancer Center will address the management of patients with acute promyelocytic leukemia (APL). While APL is one of the most curable leukemias, determination of the best treatment regimen and prevention of early deaths remain important issues.
2. Dr. Frederick Appelbaum of the Fred Hutchinson Cancer Research Center will discuss the complicated and sometimes frustrating problem of patients with AML who have complex cytogenetic abnormalities. It is increasingly clear that these patients are not all the same and might require different treatments.
3. Although childhood ALL is curable in 80% to 90% of patients, we have not been able to achieve the same good results in adults. This difficult clinical problem will be addressed by Dr. Hagop Kantarjian of the MD Anderson Cancer Center.
4. Imatinib has revolutionized treatment for patients with CML. However, new drugs might offer an even better outcome. Dr. John Goldman of Hammersmith Hospital, London, will address the question of whether imatinib continues to be suitable for the primary treatment of these patients.
5. Although most patients with CLL have a reasonably good outlook with current therapies, and some require no treatment at all for extended periods of time, those whose cancer cells have a 17p deletion have done much less well. This clinical dilemma will be discussed by Drs. John Byrd and Deborah Stephens from Ohio State University.
6. For patients whose CLL transforms to a high-grade lymphoma (usually diffuse large B-cell lymphoma), the prognosis has been terrible. Dr. Susan O'Brien of the MD Anderson Cancer Center will address the contemporary management of patients with Richter’s syndrome.
ONCOLOGY has a history of clinically relevant reviews that are torn out and kept in physicians’ files for use with future patients. This series of articles on interesting and complicated clinical problems in leukemia, authored by leading leukemia experts, will keep this tradition alive.
1. Swerdlow SH. WHO classification of tumours of haematopoietic and lymphoid tissues. 4th ed. Lyon, France: International Agency for Research on Cancer; 2008.