Department of Medical Physics, Faculty of Medicine, University of Crete, P.O. Box 2208, Heraklion 71003, Crete, Greece.
Department of Medical Physics, Faculty of Medicine, University of Crete, P.O. Box 2208, Heraklion 71003, Crete, Greece.
Phys Med. 2019 Jan;57:100-106. doi: 10.1016/j.ejmp.2018.12.036. Epub 2019 Jan 3.
To estimate the second cancer risk associated with Hodgkin Lymphoma (HL) radiotherapy at supradiaphragmatic or infradiaphragmatic region, using the involved field (IFRT) and the involved site radiotherapy (ISRT).
IFRT and ISRT treatment plans were created for twenty HL patients. Three dimensional plans (3DRT) were employed for all patients. The organ equivalent dose (OED) and lifetime attributable risk (LAR) for organs at risk were estimated with mechanistic, plateau and bell-shaped model. Estimated risk values were compared with nominal risk of unexposed population.
For supradiaphragmatic radiotherapy, the mean OED range was 0.63-8.53 Gy and 0.63-7.26 Gy for IFRT and ISRT, respectively. The corresponding range for infradiaphragmatic radiotherapy was 0.18-7.64 Gy and 0.80-4.95 Gy. The LAR for cancer induction in the partially in field organs at risk after IFRT was 0.5%-8.0% and 0.2%-9.3% at supradiaphragmatic and infradiaphragmatic regions, respectively. The corresponding risk after ISRT method was 0.5%-5.2% and 0.9%-6.0%. Estimated cancer risk for breast, lung, thyroid, colon and rectal with ISRT was found significantly reduced compared to IFRT. The risk of secondary malignancies for lung, mouth, pharynx, rectum and colon was assessed more than 1.2 times higher than nominal risk for IFRT. The respective risk using ISRT was above nominal only for pharyngeal cancer.
ISRT compared with IFRT, results in decreased second cancer risk in most organs considered. Second cancer probability with IFRT was higher than the nominal risk for certain organs, while for ISRT remains higher only for pharyngeal cancer.
使用累及野放疗（IFRT）和累及部位放疗（ISRT），估算膈上或膈下霍奇金淋巴瘤（HL）放疗的第二癌症风险。
为 20 例 HL 患者制定 IFRT 和 ISRT 治疗计划。所有患者均采用三维放疗（3DRT）。采用机制模型、平台模型和钟形模型估算危险器官的组织等效剂量（OED）和终生归因风险（LAR）。将估计的风险值与未暴露人群的名义风险进行比较。
对于膈上放疗，IFRT 和 ISRT 的平均 OED 范围分别为 0.63-8.53 Gy 和 0.63-7.26 Gy。膈下放疗的相应范围为 0.18-7.64 Gy 和 0.80-4.95 Gy。IFRT 后部分场内危险器官癌症诱导的 LAR 分别为膈上和膈下 0.5%-8.0%和 0.2%-9.3%。ISRT 方法的相应风险为 0.5%-5.2%和 0.9%-6.0%。与 IFRT 相比，ISRT 后乳腺、肺、甲状腺、结肠和直肠的癌症风险明显降低。肺、口腔、咽、直肠和结肠的继发性恶性肿瘤风险评估值比 IFRT 的名义风险高 1.2 倍以上。仅在咽癌中，使用 ISRT 的风险高于名义风险。
与 IFRT 相比，ISRT 可降低大多数考虑的危险器官的第二癌症风险。IFRT 的第二癌症概率对于某些器官高于名义风险，而对于 ISRT 仅对于咽癌仍然较高。
