Comparison of Volumetric and Dosimetric Variations in Nasopharyngeal Carcinoma during Intensity-modulated Radiation Therapy with and without Neoadjuvant Chemotherapy
Zhaodong Fei1, Yi Li1, Xiufang Qiu1, Yingying Huang1, Li Li1, Chuanben Chen1,2
1. Department of Radiotherapy,Fujian Medical University Cancer Hospital,Fujian Provincial Cancer Hospital,Fuzhou Fujian Province 350014,China; 2. Department of Radiation Oncology,Fujian Medical University Cancer Hospital,Fujian Provincial Cancer Hospital,Fuzhou Fujian Province 350014,China
AbstractObjective Patients with nasopharyngeal carcinoma (NPC) undergoing intensity-modulated radiation therapy (IMRT) may experience significant volumetric and dosimetric variations throughout the treatment course. However,neoadjuvant chemotherapy may reduce the extent of these variations. This study was carried out to evaluate volumetric and dosimetric changes in target volumes and organs at risk (OARs) during IMRT in patients with locally advanced NPC who received concurrent chemoradiotherapy (CCRT) alone or in combination with neoadjuvant chemotherapy (NACT). Methods 35 NPC patients were recruited for this study and divided into the NACT (n=15) and CCRT (n=20) groups. Computed tomography (CT) scans were performed before neoadjuvant chemotherapy,before IMRT,before the 24th fraction of IMRT,and after treatment. The original plan (plan 0) was based on CT images collected before IMRT. Hybrid plan 1 (plan 1) and hybrid plan 2 (plan 2) were generated by applying the beam configurations of plan0 to the CT scans collected before the 24th fraction of IMRT and after treatment. Volumetric and dosimetric variations were assessed by comparing the results of plan 0 with those of plan 1 and plan 2. Results In the NACT group,compared with that in plan 0,the primary gross tumor volume (GTVnx) decreased by 33.2%±18.4% and 50.5%±12.6% in plan1 and plan 2,respectively. In the CCRT group,the corresponding reduction rates in plan 1 and plan 2 were 49.4%±8.0% and 77.8%±28.1%,respectively. The volume decrease rates in the NACT group were less than those in the CCRT group (P<0.001). In the NACT group,compared with that of plan 0,the dose to 95% of the volume (D95) for the planning target volume of the primary tumor (PTVnx) decreased by 1.0%±0.7% and 0.6%±0.6% in plan 1 and plan 2,respectively. In the CCRT group,the corresponding decrease rates in plan 1 and plan 2 were 4.2%±3.8% and 6.1%±6.3%,respectively. The decrease rate of D95 for PTVnx in the NACT group was less than that in the CCRT group (P<0.001). Similar results among the plans were found in terms of D99,Dmean,V93 for PTVnx and PTVnd,and Dmean for the parotid glands. Conclusion Neoadjuvant chemotherapy reduces the extent of volumetric and dosimetric variations in target volumes and OARs during IMRT and,thus,helps achieve better target volume coverage,protects adjacent important structures,and minimizes unnecessary replanning during radiotherapy.
Zhaodong Fei,Yi Li,Xiufang Qiu, et al. Comparison of Volumetric and Dosimetric Variations in Nasopharyngeal Carcinoma during Intensity-modulated Radiation Therapy with and without Neoadjuvant Chemotherapy[J]. Chinese Journal of Biomedical Engineering, 2020, 29(3): 24-32.
[1] Lee AW,Ma BB,Ng WT,et al.Management of nasopharyngeal carcinoma: current practice and future perspective[J]. J Clin Oncol,2015,33:3356-3364. [2] Zhang MX,Li J,Shen GP,et al.Intensity-modulated radiotherapy prolongs the survival of patients with nasopharyngeal carcinoma compared with conventional two-dimensional radiotherapy: A 10-year experience with a large cohort and long follow-up[J]. Eur J Cancer,2015,51:2587-2595. [3] Peng G,Wang T,Yang KY,et al.A prospective,randomized study comparing outcomes and toxicities of intensity-modulated radiotherapy vs. conventional two-dimensional radiotherapy for the treatment of nasopharyngeal carcinoma[J]. Radiother Oncol,2012,104:286-293. [4] Lin S,Pan J,Han L,et al.Update report of nasopharyngeal carcinoma treated with reduced-volume intensity-modulated radiation therapy and hypothesis of the optimal margin[J]. Radiother Oncol,2014,110:385-389. [5] Senkus-Konefka E,Naczk E,Borowska I,et al.Changes in lateral dimensions of irradiated volume and their impact on the accuracy of dose delivery during radiotherapy for head and neck cancer[J]. Radiother Oncol,2006,79:304-309. [6] Ajani AA,Qureshi MM,Kovalchuk N,et al.A quantitative assessment of volumetric and anatomic changes of the parotid gland during intensity-modulated radiotherapy for head and neck cancer using serial computed tomography[J]. Med Dosim,2013,38:238-242. [7] Bando R,Ikushima H,Kawanaka T,et al.Changes of tumor and normal structures of the neck during radiation therapy for head and neck cancer requires adaptive strategy[J]. J Med Invest,2013,60:46-51. [8] Brouwer CL,Steenbakkers RJ,Langendijk JA,et al.Identifying patients who may benefit from adaptive radiotherapy: Does the literature on anatomic and dosimetric changes in head and neck organs at risk during radiotherapy provide information to help?[J]. Radiother Oncol,2015,115:285-294. [9] Zhang Y,Chen L,Hu GQ,et al.Gemcitabine and cisplatin induction chemotherapy in nasopharyngeal carcinoma[J]. N Engl J Med,2019,381:1124-1135. [10] Liu L,Fei Z,Chen M,et al.Induction chemotherapy plus concurrent chemoradiotherapy versus induction chemotherapy plus volumetric modulated arc therapy alone in the treatment of stage II-IVB nasopharyngeal carcinoma patients:a retrospective controlled study[J]. Radiat Oncol,2018,13:148. [11] Peng L,Xu C,Chen YP,et al.Optimizing the cumulative cisplatin dose during radiotherapy in nasopharyngeal carcinoma:Dose-effect analysis for a large cohort[J]. Oral Oncol,2019,89:102-106. [12] Lokesh KN,Chaudhuri T,Lakshmaiah KC,et al.Induction chemotherapy in locoregionally advanced nasopharyngeal carcinoma in adults:Results from a nonendemic region[J]. Indian J Cancer,2018,55:257-260. [13] Zhao L,Wan Q,Zhou Y,et al.The role of replanning in fractionated intensity modulated radiotherapy for nasopharyngeal carcinoma[J]. Radiother Oncol,2011,98:23-27. [14] Bhide SA,Davies M,Burke K,et al.Weekly volume and dosimetric changes during chemoradiotherapy with intensity-modulated radiation therapy for head and neck cancer:a prospective observational study[J]. Int J Radiat Oncol Biol Phys,2010,76:1360-1368. [15] Castadot P,Geets X,Lee JA,et al.Assessment by a deformable registration method of the volumetric and positional changes of target volumes and organs at risk in pharyngo-laryngeal tumors treated with concomitant chemo-radiation[J]. Radiother Oncol,2010,95:209-217. [16] Hansen EK,Bucci MK,Quivey JM,et al.Repeat CT imaging and replanning during the course of IMRT for head-and-neck cancer[J]. Int J Radiat Oncol Biol Phys,2006,64:355-362. [17] Robar JL,Day A,Clancey J,et al.Spatial and dosimetric variability of organs at risk in head-and-neck intensity-modulated radiotherapy[J]. Int J Radiat Oncol Biol Phys,2007,68:1121-1130. [18] Hui EP,Ma BB,Leung SF,et al.Randomized phase II trial of concurrent cisplatin-radiotherapy with or without neoadjuvant docetaxel and cisplatin in advanced nasopharyngeal carcinoma[J]. J Clin Oncol,2009,27:242-249. [19] Lee AW,Lau KY,Hung WM,et al.Potential improvement of tumor control probability by induction chemotherapy for advanced nasopharyngeal carcinoma[J]. Radiother Oncol,2008,87:204-210. [20] Ferrari D,Chiesa F,Codecà C,et al.Locoregionally advanced nasopharyngeal carcinoma:induction chemotherapy with cisplatin and 5-fluorouracil followed by radiotherapy and concurrent cisplatin:a phase II study[J]. Oncology,2008,74:158-166. [21] Airoldi M,Gabriele AM,Garzaro M,et al.Induction chemotherapy with cisplatin and epirubicin followed by radiotherapy and concurrent cisplatin in locally advanced nasopharyngeal carcinoma observed in a non-endemic population[J]. Radiother Oncol,2009,92:105-110. [22] Wu Q,Chi Y,Chen PY,et al.Adaptive replanning strategies accounting for shrinkage in head and neck IMRT[J]. Int J Radiat Oncol Biol Phys,2009,75:924-932. [23] Wang W,Yang H,Hu W,et al.Clinical study of the necessity of replanning before the 25th fraction during the course of intensity-modulated radiotherapy for patients with nasopharyngeal carcinoma[J]. Int J Radiat Oncol Biol Phys,2010,77:617-621. [24] Yang H,Hu W,Ding W,et al.Changes of the transverse diameter and volume and dosimetry before the 25th fraction during the course of intensity-modulated radiation therapy (IMRT) for patients with nasopharyngeal carcinoma[J]. Med Dosim,2012,37:225-229.
