Effect of Akimbo versus Raised Arm Positioning on Breast and Cardiopulmonary Dosimetry in Pediatric Hodgkin Lymphoma

PURPOSE: In pediatric Hodgkin lymphoma (HL), radiotherapy (RT)-related late toxicities are a prime concern during treatment planning. This is the first study to examine whether arm positioning (raised versus akimbo) result in differential cardiopulmonary and breast doses in patients undergoing mediastinal RT. METHODS: Two treatment plans were made for each patient (akimbo/arms raised); treatment was per Children’s Oncology Group AHOD0031 protocol, including AP/PA fields. The anterior midline T6–T7 disk space was used as an anatomic reference of “midline.” Heart/lungs were contoured for each setup. For females, breasts were also contoured and nipple positions identified. Volumetric centers of contoured organs were defined and three-dimensional distances from “midline” were computed. Analyzed dosimetric parameters included V5 (volume receiving ≥5 Gy), V10, V15, V20, and mean dose. Statistics were performed using the Mann–Whitney test. RESULTS: Fifteen (6 females, 9 males) pediatric HL patients treated with mediastinal RT were analyzed. The median lateral distance from the breast center/nipple to “midline” with arms akimbo was larger than that with arms raised (8.6 vs. 7.7 cm left breast, p = 0.04; 10.7 vs. 9.2 cm left nipple, p = 0.04; 8.7 vs. 7.0 cm right breast, p = 0.004; 9.9 vs. 7.9 cm right nipple, p = 0.007). Raised arm position was associated with a median 2.8/3.0 cm decrease in breast/nipple separation, respectively. There were no significant differences in craniocaudal breast/nipple position based on arm positioning (p > 0.05). Increasing breast volume was correlated with larger arm position-related changes in breast/nipple separation (r = 0.74, p = 0.06/r = 0.85, p = 0.02). Akimbo positioning lowered median breast V5, V10, V15, and mean dose (p < 0.05), with no differences observed in patients with both mediastinal and axillary disease for any parameters (p > 0.05). Arm position had no significant effect on cardiopulmonary doses. CONCLUSION: Akimbo arm positioning may be advantageous to decrease breast doses in female pediatric HL patients undergoing mediastinal RT, especially in the absence of axillary disease.