In a recent article published in the Journal of the National Cancer Institute, researchers have determined a relationship between radiation doses to heart valves and the significant increased risk of developing valvular heart disease (VHD).

In a case-controlled study that looked at a cohort of 1,852 five-year survivors of Hodgkin’s Lymphoma (HL), the research team studied Case patients had VHD of at least moderate severity as their first cardiovascular diagnosis following HL treatment. Control patients were matched to case patients for age, gender, and HL diagnosis date.

“This study provides, for the first time, quantitative estimates of the relationship between radiation dose to the heart valves and subsequent risk of clinically significant VHD,” wrote the study team, including David Cutter with the University of Oxford.

The results showed that aortic and mitral valves were most frequently affected and risks increased more than linearly with radiation dose.

“Approximate 30-year cumulative risks were 3.0, 6.4, 9.3, and 12.4 percent for the same dose categories. VHD rate increased with splenectomy by a factor of 2.3,” the researchers wrote.

Hodgkin lymphoma is a curable malignancy and treatment has improved over the last 50 years, resulting in a survival rate of more than 80 percent.

“However, it is well documented that radiotherapy (RT), as given in the past for HL, is an important cause of increased cardiovascular mortality and morbidity in long-term survivors,” Cutter et al wrote.

Additionally, increased recognition of this risk and combination treatment including both chemotherapy and RT has led to a reduction in doses and volumes of RT used for HL.

“This study confirms that radiation dose to the heart valves is the main risk factor for the development of clinically significant VHD following treatment for HL,” the authors concluded. “It is the first time that a dose-response relationship has been derived in terms that can be easily translated into clinical practice. It will help clinicians assess the risk of VHD for patients treated in the future and will assist in guiding the appropriate follow-up of HL survivors.”