Impact of changing gross tumor volume delineation of intensity-modulated radiotherapy on the dose distribution and clinical treatment outcome after induction chemotherapy for the primary locoregionally advanced nasopharyngeal carcinoma
10.3321/j.issn:1000-467X.2009.11.003
- VernacularTitle:诱导化疗后局部晚期鼻咽癌调强放疗肿瘤靶区勾画方式改变对剂量分布和临床疗效的影响
- Author:
Yu ZHAN
1
;
Luo WEI
;
Zhou QI-CHAO
;
Zhang QIN-HUA
;
Kang DE-HUA
;
Liu MENG-ZHONG
Author Information
1. 中山大学肿瘤防治中心
- Keywords:
nasopharyngeal neoplasm;
induction chemotherapy;
intensity-modulated radiation therapy;
radiotherapy;
target volume delineation;
dose distribution;
clinical therapeutic effect;
toxicity
- From:Chinese Journal of Cancer
2009;28(11):1132-1137
- CountryChina
- Language:Chinese
-
Abstract:
Background and Objective:The gross tumor volume (GTV) obviously reduces after induction chemotherapy (IC) for primary Iocoregionally advanced nasopharyngeal carcinoma (NPC). This study was to investigate the impact of changing gross tumor volume delineation on the dose distribution and clinical treatment outcome after IC. Methods: From January 2008 to April 2009, 24 patients with Stage Ⅲ-Ⅳb primary locoregionally advanced NPC were treated with TPF regimen IC followed by intensitymodulated radiotherapy (IMRT) with concurrent chemotherapy The primary GTVs were delineated into two parts: the post-IC primary GTV (GTVpost-IC-NP),and the region of pre-IC primary GTV minus GTVpost-IC-NP (GTVprepost-IC-NP). The dose distributions of two plans with GTVpost-IC-NP or pre-IC primary GTV were assessed by analyzing ten cases. The clinical treatment outcome and toxicity of all patients were observed. Results:The post-IC GTV was significantly smaller than the pre-IC GTV(primary GTV 25.5 cm~3 vs.51.1 cm~3,P=0.001;lymph nodes GTV 9.1 cm~3 vs. 31.4 cm~3, P=0.035;primary+lymph nodes GTV 33.2 cm~3 vs. 82.6 cm~3, P=0.004), the overall GTV with an average shrinkage of 61%. The high dose region was also smaller after IC(volumes covered by 64.4 Gy were 422.9 cm~3 vs.457.9cm~3, P=0.003; 274.2 cm~3 vs.334.5 cm~3 by 68 Gy, P=0.041). The complete response rate was 38% after IC,and 100% three month after radiotherapy.The toxicity of following IMRT with concurrent chemotherapy was similar to that of IMRT with concurrent chemotherapy alone. With median follow-up of 9 months, the locoregionally control rate was 100% and only one patient presented metastasis 15 months after treatment. Gonclusions: TPF regimen IC could significantly reduce tumor volume. The following IMRT with GTVpost-IC-NP plan reduced the high dose region,which didn't add toxicity while had excellent short-term treatment outcome.
