Radiotherapy treatments for Hodgkin lymphoma may raise the risk of certain breast cancer subtypes, a study of data on women survivors from the Surveillance, Epidemiology, and End Results (SEER) registries revealed.
In a recent study, Hodgkin lymphoma survivors were more likely to develop estrogen receptor (ER)-negative or -positive breast cancer compared to the general population, and those treated with radiotherapy also showed increased odds for developing the disease.
These findings were based on the largest study to date aimed at assessing the impact of radiotherapy for Hodgkin lymphoma on the risk of breast cancer with respect to ER status. They were published in a research letter in JAMA Oncology.
“Survivors of Hodgkin lymphoma have a high risk of developing a subsequent breast cancer, particularly after chest irradiation,” researchers from the Radiation Epidemiology Branch in the Division of Cancer Epidemiology and Genetics at the National Cancer Institute in Bethesda, Maryland, wrote. “Although breast cancer is a heterogeneous disease, the association between Hodgkin lymphoma treatment and the ER status of subsequent breast cancers has not been examined in large cohorts.”
Therefore, the researchers used Surveillance, Epidemiology, and End Results (SEER) registries to identify 7,355 women—aged 10 to 39 years–who were diagnosed with first, primary Hodgkin lymphoma between 1973 and 2009. Follow-up for these patients began 5 years after their Hodgkin lymphoma diagnosis and ended at breast cancer diagnosis, last known status or death.
Of the 377 invasive breast cancers diagnosed among survivors, 57% were ER-positive, 34% were ER-negative and 9% were unknown or had borderline ER status.
ER-negative cancers appeared to be nearly 6 times more common among Hodgkin lymphoma survivors compared with the general population, and 3 times more common for ER-positive cancers.
These risks also varied by treatment. For example, the risk for ER-negative breast cancer was higher for all survivors, however, only those who received radiotherapy experienced higher risks for ER-positive disease.
“Despite changes in treatment recommendations, 40% of young women with Hodgkin lymphoma currently receive radiotherapy, which was associated with an increased risk of ER-positive breast cancer in our study,” the researchers wrote.
The researchers noted that additional studies are necessary to better understand these findings.
“Further investigation of the association between Hodgkin lymphoma treatment and breast cancer subtype in studies with comprehensive treatment records will lead to a better understanding of the risk and etiology of subsequent breast cancers and can ultimately inform treatment and screening decisions to reduce morbidity and mortality among Hodgkin lymphoma survivors,” the researchers wrote.