The safety and protective effect on resting dry mouth of optimized dose optimization in clinical target volume Ⅱa in patients with N 0-N 1 nasopharyngeal carcinoma
10.3760/cma.j.cn113030-20231007-00113
- VernacularTitle:鼻咽癌N 0-N 1期患者Ⅱa区临床靶区优化策略及对远期口干的影响
- Author:
Wenxuan HUANG
1
;
Shengfu HUANG
;
Siyu ZHANG
;
Lanfang ZHANG
;
Lijun WANG
;
Juying LIU
;
Yizhi GE
;
Xia HE
Author Information
1. 南京医科大学附属肿瘤医院/江苏省肿瘤医院/江苏省肿瘤防治研究所放疗科，南京210009
- Keywords:
Nasopharyngeal carcinoma;
Target optimization;
Submandibular gland;
Resting mouth dry;
Suspicious cervical lymph nodes
- From:
Chinese Journal of Radiation Oncology
2024;33(5):397-404
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze the safety of reduced clinical target volume (CTV) irradiation of suspicious positive lymph nodes in IIa region in patients with N 0-N 1 nasopharyngeal carcinoma (NPC) and the protective effect of submandibular gland and long-term resting dry mouth, and to explore the diagnostic value of multimodal imaging for suspicious cervical lymph nodes. Methods:Clinical data of T 0-4N 0-1M 0 stage NPC patients admitted to Jiangsu Cancer Hospital from July 2015 to April 2017 were retrospectively analyzed. Clinical, radiation therapy planning, multimodal imaging and other relevant data were collected. All patients were treated with an optimized regimen of IMRT with a prophylactic radiation dose of 50.4 Gy (named as CTV50) for IIa region. Imaging characteristics and treatment response of suspicious lymph nodes were monitored by MRI, MRI-DWI, PET-CT and repeated enhanced positioning CT, etc. The dosimetry of the submandibular gland between optimized and standard dose plans (CTV50 vs. CTV60) was compared by paired t-test. The long-term dry mouth degree of the patients was evaluated using advanced radiation injury from Radiation Therapy Oncology Group (RTOG), Jiangsu Cancer Hospital Multi-dimensional Dry Mouth Evaluation Scale and summated xerostomia inventory (SXI). The difference of dry mouth degree was analyzed by rank-sum test. Results:A total of 106 patients were included in this study, including 149 cervical lymph node negative sides, 73 sides of which had ≤3 recognizable lymph nodes, and 76 of which were>3 in Ⅱa region. Among patients with N 1 stage, 63 patients underwent contralateral single neck area optimization, and 43 patients (N 0 stage and N 1 stage patients with retropharyngeal lymph node metastasis) underwent double-neck area optimization. A total of 109 suspicious lymph nodes with a short diameter of >5 mm were found on the largest cross section, of which 105 had clear portal structure. The ratio of long to short diameter was ≥1.5 in 93 cases, and the maximum standardized uptake value (SUV max) in PET-CT was ≥2.5 in 76 cases. No lymph node recurrence was found in the CTV optimized area. There was no significant difference in the average dose of GTV in tumor target area after optimization ( P>0.05), and the D mean and V 39 Gy in submandibular gland were significantly lower than those in unoptimized plan (both P<0.01). There was no significant difference in long-term dry mouth and resting dry mouth between patients with unilateral and bilateral optimization of submandibular gland (both P>0.05). Conclusions:The optimal program of CTV50 reduction irradiation in Ⅱa area of N 0-N 1 NPC patients is safe and effective. The submandibular gland has obvious dosimetric advantages, and patients have a good subjective response to resting dry mouth. The multimodal imaging tools such as enhanced CT, MRI-DWI and PET-CT should be performed to deliver individual evaluation and treatment for suspicious lymph nodes.
