Fontenla S, Wang T, Lee N, McCann P, Young R, Mechalakos J
Memorial Sloan Kettering Cancer Center, New York, NY.
College of Physicians and Surgeons, Columbia University, New York, New York.
Med Phys. 2012 Jun;39(6Part19):3840. doi: 10.1118/1.4735672.
Nausea and vomiting have been known to occur in patients undergoing external beam radiation treatments for head&neck cancers. We sought to determine the feasibility of limiting the dose delivered to the nausea center, area postrema (AP) and dorsal vagal complex (DVC), for these patients without compromising target coverage and critical organ doses.
In a retrospective study 23 oropharyngeal cancer patients were identified as being treated with definitive or adjuvant radiotherapy at Memorial Sloan Kettering Cancer Center. Patients were treated solely with external beam radiation using intensity modulated radiation therapy (IMRT). The nausea center was carefully contoured in the treatment CT with the assistance of a board certified neuroradiologist. The doses delivered to the nausea center were calculated for each plan delivered. Cases were replanned offline to determine the lowest achievable nausea center dose that does not compromise the overall PTV coverage or critical structures doses, these being brainstem, spinal cord, cochleas, and temporal lobes.
Patients reporting higher nausea grade had median AP and DVC doses of 38.7Gy and 40.4Gy, respectively. Patients reporting higher vomiting grade had median AP and DVC doses of 39.5Gy and 44.7Gy, respectively. Replanning resulted in reduced dose to AP by an average of 18% and to the DVC by an average of 16% while maintaining adequate target coverage and doses to the critical organs the same or decreased by 1-4% . We aim to achieve a max dose of 36Gy to AP and 38Gy to DVC for these cases.
It is feasible to limit the doses to the nausea center without compromising target coverage or critical organ limits for oropharyngeal cancer patients undergoing IMRT treatment. Clinical results indicating an association between radiation dose to the nausea center and development of nausea and/or vomiting can potentially be addressed by implementing this technique.
已知接受头颈部癌外照射放疗的患者会出现恶心和呕吐。我们试图确定在不影响靶区覆盖和关键器官剂量的情况下，限制给予恶心中枢、最后区（AP）和迷走神经背核复合体（DVC）剂量的可行性。
在一项回顾性研究中，确定了23例在纪念斯隆凯特琳癌症中心接受根治性或辅助性放疗的口咽癌患者。患者仅接受使用调强放射治疗（IMRT）的外照射放疗。在一名获得委员会认证的神经放射科医生的协助下，在治疗CT上仔细勾勒出恶心中枢。计算每个治疗计划给予恶心中枢的剂量。离线重新规划病例，以确定在不影响总体计划靶体积（PTV）覆盖或关键结构剂量（即脑干、脊髓、耳蜗和颞叶）的情况下可实现的最低恶心中枢剂量。
报告恶心程度较高的患者，AP和DVC的中位剂量分别为38.7Gy和40.4Gy。报告呕吐程度较高的患者，AP和DVC的中位剂量分别为39.5Gy和44.7Gy。重新规划使AP剂量平均降低18%，DVC剂量平均降低16%，同时保持足够的靶区覆盖，关键器官的剂量相同或降低1 - 4%。对于这些病例，我们的目标是使AP的最大剂量达到36Gy，DVC的最大剂量达到38Gy。
对于接受IMRT治疗的口咽癌患者，在不影响靶区覆盖或关键器官剂量限制的情况下，限制给予恶心中枢的剂量是可行的。通过实施该技术，可能可以解决表明恶心中枢辐射剂量与恶心和/或呕吐发生之间存在关联的临床结果。
