鼻咽癌放射性口干症与腮腺受照射体积相关性研究

Relationship between radiation-induced xerostomia and the volume of parotid glands exposed in radiotherapy for nasopharyngeal carcinoma

目的研究腮腺体积大小与鼻咽癌放射性口干症的关系。方法选取2015--2016年收治的199例鼻咽癌患者。根据腮腺大小分为大腮腺组与小腮腺组，并对两组患者放疗后口干情况进行对比，同时对两组之间的剂量学指标进行比较分析。计数资料采用驴检验，计量资料采用χ^2检验或非参数Mann—WhitneyU检验。对DVH指标行非参数Mann—WhitneyU检验。结果两组患者放疗后3、6个月口干程度无差异，放疗后1年大腮腺组患者口干程度较小腮腺组轻（P=0．035）。两组患者双侧腮腺受量不同．小腮腺组患者双侧腮腺受量高于大腮腺组，而两组患者颌下腺平均受量相近。结论腮腺初始体积大小是影响放疗后口干评级的因素之一。大腮腺患者放疗后口干恢复情况优于小腮腺患者；对于小腮腺患者在计划制作时应更加注意降低剂量保护腮腺组织。

Objective To evaluate the relationship between the volume of parotid glands and radiation-induced xerostomia in patients with nasopharyngeal carcinoma （NPC）. Methods A total of 199 patients with NPC who were admitted to our hospital from 2015 to 2016 were enrolled as subjects. According to the initial volume of parotid glands, all patients were divided into large parotid group and small parotid group. The incidence of xerostomia after radiotherapy and dosimetrie parameters were compared between the two groups. Comparison of categorical data was made by χ^2 test. Comparison of continuous data was made by t-test or nonparametric test. Comparison of dose-volume histogram index was made by nonparametric test. Results There was no difference in the severity of xerostomia between the two groups at 3 and 6 months after radiotherapy. At one year after radiotherapy, the large parotid group had significantly milder xerostomia than the small parotid group （P= 0. 035）.The small parotid group had a higher dose delivered to both parotid glands than the large parotid group. There was no difference in the mean dose to the submandibular gland between the two groups. Conclusions The initial volume of parotid glands is one of the influencing factors for the grade of xerostomia after radiotherapy. Patients with large parotid glands have better recovery from xerostomia after radiotherapy than those with small parotid glands..For patients with small parotid glands, more attention should be paid to reducing the dose to protect parotid glands.