(S041) Intensity-Modulated Involved-Site Radiation Therapy for Non-Hodgkin Lymphoma of the Head and Neck
Outcomes for head and neck NHL were maintained using ISRT with IMRT, with no marginal failures. ISRT reduces dose to normal tissues, and our results suggest that further reductions can be achieved with IMRT. This approach may be most valuable for definitive treatment of early-stage NHL, as the excellent prognosis highlights the importance of minimizing RT sequelae.
Zachary D. Guss, MD, MSc, Abdossalam M. Madkhali, MBBS, MSc, Yin Zhang, PhD, Samson Dah, BS, Joseph Moore, PhD, Stephanie A. Terezakis, MD; Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University; Oxford Institute for Radiation Oncology, University of Oxford; Department of Medicine, King Saud University
PURPOSE/OBJECTIVES: Involved-field radiation therapy (IFRT) for non-Hodgkin lymphoma (NHL) of the head and neck has historically been delivered using conventional techniques. Modern techniques, such as intensity-modulated radiation therapy (IMRT) and involved-site radiation therapy (ISRT), may spare normal tissues and maintain excellent clinical outcomes.
MATERIALS AND METHODS: A retrospective study was conducted of patients aged > 18 years at diagnosis of NHL and involvement of the head and neck treated with ISRT using IMRT. Patients were evaluated for local control, overall survival (OS), and radiation-related toxicities. Conventional ISRT (c-ISRT) and IFRT (c-IFRT) treatment plans were also generated. A paired t-test was used to evaluate whether the RT approach resulted in differences in dose to organs at risk. Excess absolute risk (EAR) of secondary malignancy due to RT was calculated using the linear no-threshold model and parameters derived from the organ equivalent dose concept and Biological Effects of Ionizing Radiation VII report.
RESULTS: A total of 21 patients with a median age of 61 years (range: 32–85 yr) and a median follow-up of 31 months (range: 2–55 mo) were evaluated. Fifteen (71%) patients had early-stage (I/II) NHL, and six (29%) had advanced-stage NHL. OS for early-stage patients was 100%. Two patients failed locally, both in-field in the context of aggressive advanced-stage disease. Toxicities were mild. Dmax to the spinal cord and brainstem was the lowest using IMRT (P < .05). EAR for early-stage patients per 10,000 person-years for IMRT was 11.7, lower than that of c-ISRT (15.3; P = .02) and c-IFRT (12.8; P = .04).
CONCLUSION: Outcomes for head and neck NHL were maintained using ISRT with IMRT, with no marginal failures. ISRT reduces dose to normal tissues, and our results suggest that further reductions can be achieved with IMRT. This approach may be most valuable for definitive treatment of early-stage NHL, as the excellent prognosis highlights the importance of minimizing RT sequelae.
Proceedings of the 98th Annual Meeting of the American Radium Society -americanradiumsociety.org
