Klin Padiatr 2014; 226 - P_19
DOI: 10.1055/s-0034-1371125

Advancing the Therapeutic Index of Pediatric Patients with Stage III and IV Hodgkin Lymphoma with Proton Therapy

B Hoppe 1, A Holtzman 1, Z Li 1, Z Su 1, W Slayton 2, S Ozdemir 3, M Joyce 4, E Sandler 4, N Mendenhall 1, S Flampouri 1
  • 1University of Florida, Radiation Oncology, Jacksonville, United States
  • 2University of Florida, Gainesville, United States
  • 3University of Florida, Jacksonville, United States
  • 4Nemours Children's Clinic and Wolfson Children's Hospital, Jacksonville, United States

Question: Hodgkin lymphoma (HL) survivors experience considerable susceptibility to the long-term side effects from definitive treatment with combination chemotherapy and radiotherapy (RT). Considering the late effects due to RT have been correlated to radiation treatment volume, pediatric patients with stage III and IV HL, may require the largest radiation fields and are likely to be at the greatest risk of late complications. This study investigates the dosimetric impact of using proton therapy to spare the organs at risk (OARs) in patients with stage III & IV HL.

Methods: From October 2011 through October 2013, six consecutive pediatric patients with stage III or IV HL involving both supradiaphragmatic and infradiaphragmatic (IVsi) following completion of 3 to 5 cycles of ABVE-PC chemotherapy underwent treatment planning with 3DCRT(AP/PA), IMRT, and PT to a dose of 21 Gy (1.5 Gy per fraction for 14 fractions). Plans were normalized to meet stringent treatment parameters including target coverage and dose to OARs.

Results: All 6 patients were treated with PT. Overall, PT had the lowest integral body dose (79J, range 55 – 139) compared with 3DCRT (186J, range 110 – 301) and IMRT (163J, range 96 – 298). PT led to a clinically significant absolute dose reduction compared with 3DCRT and IMRT in the heart ([median ]7.1 Gy and 4.2 Gy), breasts (6.4 Gy and 5.7 Gy), lungs (3.3 Gy and 2.8 Gy), stomach (11.1 Gy and 6.8 Gy), liver (4.3 Gy and 6.2 Gy), and bowel (4.8 Gy and 4.4 Gy), respectively. A less significant reduction was seen in the thyroid (1.3 Gy and 0.7 Gy), pancreas (2.1 Gy and 1.0 Gy), left kidney (2.8 Gy and 1.6 Gy), and right kidney (0.9 Gy and 3.2 Gy). No benefit was seen for the esophagus (-0.2 Gy and -0.4 Gy).

Conclusion: This investigation demonstrates reductions in integral dose and dose to the OARs with PT compared with either 3DCRT or IMRT. Many of these absolute dose reductions are clinically meaningful and are expected to lower the risk of late effects in this high risk patient population.