Young Adults with Acute Lymphoblastic Leukemia Do Well on Intensified Pediatric Chemotherapy Regimen
Adolescents and young adults with acute lymphoblastic leukemia lived longer when treated with an intensified multi-drug chemotherapy regimen that is used to treat younger children. The findings confirm previous studies showing that adolescent and young-adult patients do better on pediatric-type chemotherapy regimens. They also indicate that many of these patients can be cured with chemotherapy alone and may not need to have a bone marrow transplant, which is often recommended for patients in this age group.
Journal of Clinical Oncology, published online ahead of print, October 5, 2009 (see the journal abstract).
Acute lymphoblastic leukemia (ALL) is the most common cancer in children. Adolescents and young adults who have ALL tend to have a poorer outlook than younger children with this disease. For this reason, some doctors recommend that patients in this age group be treated with a bone marrow transplant when the disease first goes into remission. Bone marrow transplants may, however, have late effects - complications that appear months or years after treatment - on children's growth and development.
Adolescents and young adults with ALL are sometimes treated by doctors who specialize in treating children with cancer and sometimes by doctors who specialize in treating adults. Doctors who treat children use different combinations of chemotherapy drugs than doctors who treat adults. Several previous studies have shown that when young adults with ALL are treated using pediatric-type chemotherapy regimens, their disease stays in remission for longer than when they are treated with adult regimens. The reasons for this difference are unclear.
A total of 262 patients with ALL who were ages 16 to 21 at diagnosis were enrolled in this study. Based on their response to initial, or induction, treatment patients were separated into tw groups: those who responded rapidly to induction therapy, and those who responded slowly. Rapid responders were assigned at random to receive a further treatment with either standard-intensity chemotherapy or intensified multi-drug chemotherapy. Slow responders were assigned to receive intensified multi-drug chemotherapy.
The study was conducted by investigators with the Children's Oncology Group, one of 12 clinical trials cooperative groups supported by the National Cancer Institute. The lead investigator was James B. Nachman, M.D., of the University of Chicago Children's Hospital.
Among rapid responders to induction therapy who went on to receive intensified chemotherapy, 83 percent were alive after 5 years and 82 percent had not had a relapse. Among rapid responders treated with standard-intensity chemotherapy, 76 percent were alive after 5 years and 67 percent had not had a relapse.
Among slow responders, 71 percent of patients were free of relapse after 5 years. When both rapidly responding and slowly responding patients were analyzed together, 78 percent were alive at 5 years and 72 percent had not had a relapse.
This study confirms previous studies showing that young adults with ALL do better when they are treated using pediatric chemotherapy regimens, the authors write. Because the patients do so well on pediatric-type chemotherapy, they continue, routinely recommending a bone marrow transplant when the cancer first goes into remission seems unnecessary.
"This study offers convincing evidence that patients in the 16 to 21-year age range with ALL should be treated with a pediatric-type ALL regimen," said Malcolm Smith, M.D., Ph.D., a pediatric cancer specialist with NCI's Cancer Therapy Evaluation Program. "When these patients do so well on chemotherapy, bone marrow transplantation - with its potential long-term complications - becomes much less attractive. For young patients who hopefully have a full life ahead of them, we would like to avoid the risk of late effects from transplantation."
The distinctive way in which pediatric-type chemotherapy regimens combine different types of drugs may explain why adolescents and young adults with ALL do better when they are treated with such regimens than when they are treated with chemotherapy regimens used in adults, Dr. Smith added. A trial now under way may confirm the effectiveness of combination therapy in young adults with ALL. In this trial, patients ages 16 to 39 with ALL are being treated with a pediatric-type regimen by doctors who specialize in treating adults.