Survivors of Hodgkin’s lymphoma (HL) have an increased risk of developing secondary malignancies and cardiovascular disease. This risk is directly correlated to the amount of radiation exposure and is significant even with the use of modern radiation therapy modalities. Deep inspiration breath hold (DIBH) techniques have been shown to lead to the delivery of lower amounts of radiation to organs at risk (OARs) during the treatment of breast cancer and Hodgkin’s lymphoma. In this study, we evaluated the ability to DIBH techniques to decrease the amount of radiation exposure of OAR in 16 consecutive HL lymphoma patients with mediastinal involvement. Majority of patients had Stage II bulky disease.
For each patient four different plans were calculated – two utilizing deep inspiration breath hold technique and two with free breathing with IMRT and APPA plans created for both breathing modalities. DIBH plans delivered significantly decreased mean doses to the heart with Dmean of 474.5cGy (DIBH-IMRT) and 779.0cGy (DIBH-APPA), compared to the free breathing plans with 1125.6cGy (FB-IMRT) and 1709.3cGy (FB-APPA).
In addition, specific cardiac substructures such as the coronary arteries and the aortic valve also received reduced mean doses of radiation. The coronary arteries in DIBH-IMRT plans received on average Dmean of 888cGy, DIBH-APPA plans -1528Gy, FB-IMRT 1921cGy and DIBH-APPA – 2529cGy. Similar trend is present within the average dose delivered to the aortic valve with average Dmean for DIBH-IMRT plans of only 894cGy, compared to average Dmean of 1694cGy for DIBH-APPA plans, 2718cGy for FB-IMRT plans, and 2874cGy for FB-APPA plans.
Mean dose of lung exposure for DIBH-IMRT plans is also significantly lower than FB-IMRT plans (p=0.003). The volume of lung tissue receiving low dose radiation is significantly decreased in the DIBH-IMRT plan compered to the FB-IMRT plan, however the volume receiving 2000cGy is comparable between the DIBH and FB plans.
These findings are consistent with previous reports and suggest that utilizing DIBH could greatly decrease the radiation exposure of OAR and decrease the long-term complications young cancer survivors face.