Young women who are treated for Hodgkin lymphoma with chest radiation therapy have a high cumulative absolute risk of developing breast cancer later in life. This risk increases with age at end of follow-up, time since diagnosis, and radiation dose, according to a new study in the October 5 issue of the Journal of the National Cancer Institute.
Due to advances in the treatment of Hodgkin lymphoma, there are now many long-term survivors who are at risk for the development of secondary cancers that frequently reflect the late side effects of treatment. Second primary cancers are the leading cause of death among long-term survivors, and breast cancer is the most common secondary cancer in female Hodgkin lymphoma survivors.
To estimate the future cumulative absolute risk of breast cancer for young women treated for Hodgkin lymphoma, Lois B. Travis, M.D., of the National Cancer Institute, and colleagues analyzed data from a case–control study within an international population-based cohort of 3,817 female 1-year survivors of Hodgkin lymphoma who had been diagnosed at age 30 or younger between 1965 and 1994.
The cumulative absolute risk of developing breast cancer increased with age at end of follow-up, time since diagnosis, and radiation dose. For example, a woman who was treated for Hodgkin lymphoma at age 20 with a chest radiation dose of at least 40 Gy without alkylating agents would have a 0.4% risk of developing breast cancer by age 30, a 4.9% risk by age 40, and a 19.1% risk by age 50. By comparison, for white women in the general population, the absolute risks of breast cancer from age 20 to ages 30, 40, and 50 are, respectively, 0.04%, 0.5%, and 2.0%.
"However, it should always be noted that the gains in long-term survival provided by successful radiotherapy and chemotherapy outweigh the associated risks of breast cancer and other late sequelae. Moreover, current modifications in treatment will likely result in lower risks of breast cancer in the future," the authors write.
In an editorial, Dan L. Longo, M.D., of the National Institute on Aging, questions the continued routine use of radiation therapy for the treatment of Hodgkin disease when alternative approaches, such as combination chemotherapy alone, have similar success in curing the disease without the magnitude of late fatal complications. "We need to stop exposing women to the risk of subsequent breast cancer (and other malignancies and heart disease) by needlessly using radiation therapy as a component of their Hodgkin disease treatment," he writes. "A Pyrrhic victory in the absence of reasonable alternative ways to accomplish the goal can be tragic but necessary; a Pyrrhic victory that could be avoided while still accomplishing the goal is just foolish."