Précis: Adjuvant treatment for breast cancer increased leukemia risk
Since the mid-1970s, adjuvant chemotherapy has been widely used to treat breast cancer with regional lymph-node involvement. More recently, systemic drug therapy has been given to women with localized disease, most of whom survive for many years without a recurrence of cancer. It has been well documented that patients with breast cancer who are treated with chemotherapy, particularly regimens containing melphalan, are at increased risk of secondary leukemia (Cancer Research 1990 May 1;50(9):2741-6). In this study, the researchers evaluated the risk of acute leukemia after adjuvant chemotherapy, especially with topoisomerase II inhibitors.
A total of 3093 French women younger than 85 years who underwent surgery for breast cancer between 1982 and 1996 were evaluated. Approximately 57% of patients received radiotherapy alone and 31% had combination of radiotherapy and chemotherapy.
Ten women were diagnosed with acute leukemia by the end of 1998.
In women who received radiotherapy without chemotherapy, the risk of leukemia was similar to that of the general population.
In women who were treated with combined radiotherapy and chemotherapy, the risk of leukemia was multiplied by 28 over the general population.
In women ages 64 and younger, chemotherapy with mitoxantrone was significantly associated with an increased risk of leukemia.
In this study, combined adjuvant radiotherapy and chemotherapy including mitoxantrone is associated with an increased risk of acute leukemia in women with breast cancer. In patients who are treated with newer chemotherapy agents, such as Taxol, the risk of acute leukemia remains unknown and warrants further investigation.