Chemotherapy drugs can lead to relapse of leukemia

The chemotherapy drugs required to push a common form of adult leukemia into remission may contribute to DNA damage that can lead to a relapse of the disease in some patients, findings of a new study suggest. The research, by a team of physicians and scientists at Washington University School of Medicine in St. Louis, is published Jan. 11 in the advance online edition of Nature. For patients with acute myeloid leukemia (AML), initial treatment with chemotherapy is essential for putting the cancer into remission. Without it, most patients would die within several months. But even so, about 80 percent of AML patients die within five years when chemotherapy treatment fails to keep the cancer in remission and the disease returns. Results of the new research provide evidence for a theory that scientists have long held: Chemotherapy contributes to relapse in cancer patients by damaging DNA and generating new mutations that allow tumor cells to evolve and become resistant to treatment. "The mutations in AML patients who have relapsed are different from those present in the primary tumor, and they are more likely to have a telltale signature of DNA damage," says senior author John F. DiPersio, MD, PhD, the Virginia E. and Sam J. Golman Professor of Medicine and chief of the division of oncology. "This suggests that mutations in the relapse cells are influenced by the chemotherapy drugs the patients receive." http://www.news-medical.net/news/20120112/Chemotherapy-drugs-can-lead-to-relapse-of-leukemia.aspx