Abstract:Objective To evaluate the effect of reducing clinical target volume (CTV) on local control and overall survival in postoperative intensity‐modulated radiotherapy (IMRT), and analyze the patterns of failure, aiming to provide clinical basis for postoperative IMRT delineation of CTV for parotid gland cancer in the era of precision radiotherapy. Methods Clinical data of 126 patients who were pathologically diagnosed with parotid gland cancer and treated with parotidectomy as well as postoperative radiotherapy were retrospectively analyzed. All patients were divided into two groups according to the prozone of CTV. It was delineated to the anterior border of parotid gland in group A, and delineated to the anterior border of masseter in group B. Actuarial estimates of local recurrence‐free survival, regional recurrence‐free survival, distant metastasis‐free survival and overall survival were obtained with the Kaplan‐Meier method. Univariate prognostic analysis was performed by log‐rank test. Multivariate prognostic analysis was conducted by Cox regression model. Results The 5‐year local recurrence‐free survival (LRFS), regional recurrence‐free survival (RRFS), distant metastasis‐free survival (DMFS) and overall survival (OS) in groups A and B were 96.7% vs. 91.3%, 96.7% vs. 90.2%, 86.9% vs. 81.3% and 86.0% vs. 81.4%, respectively. There were no significant differences in these parameters between two groups. Of 126 patients with parotid carcinoma, 7 had local recurrence. There were 2 cases in group A which 1 recurred in‐field and 1 recurred out‐ field. And there were 5 cases in group B which 4 recurred in‐field and 1 recurred marginally. Univariate analysis showed that age was associated with LRFS. Age, N stage and pathological grading were associated with OS. Cox multivariate analysis revealed that age, N stage and pathological grading were the independent influencing factors of OS. Conclusions Reducing the CTV would not increase the risk of local recurrence in patients with parotid gland carcinoma without tumor extravasation and negative surgical margins. There is no significant difference in survival benefit compared to those delineated to the anterior border of the masseter muscle. The delineation of CTV should be treated differently according to the risk factors.
Dong Junya,Sun Xueming,Huang Rong et al. Clinical exploratory study on reduction of clinical target volume in postoperative intensity‐modulated radiotherapy for parotid gland cancer[J]. Chinese Journal of Radiation Oncology, 2022, 31(12): 1109-1114.
[1] Wang XD, Meng LJ, Hou TT, et al.Tumours of the salivary glands in northeastern China: a retrospective study of 2508 patients[J]. Br J Oral Maxillofac Surg, 2015,53(2):132-137. DOI: 10.1016/j.bjoms.2014.10.008. [2] Seethala RR, Stenman G.Update from the 4th edition of the World Health Organization Classification of Head and Neck Tumours: Tumors of the Salivary Gland[J]. Head Neck Pathol, 2017,11(1):55-67. DOI: 10.1007/s12105-017-0795-0. [3] Westergaard-Nielsen M, Godballe C, Eriksen JG, et al.Salivary gland carcinoma in Denmark: a national update and follow-up on incidence, histology, and outcome[J]. Eur Arch Otorhinolaryngol, 2021,278(4):1179-1188. DOI: 10.1007/s00405-020-06205-2. [4] Noh JM, Ahn YC, Nam H, et al.Treatment results of major salivary gland cancer by surgery with or without postoperative radiation therapy[J]. Clin Exp Otorhinolaryngol, 2010,3(2):96-101. DOI: 10.3342/ceo.2010.3.2.96. [5] Lv T, Wang Y, Wang X.Subgroups of parotid gland infiltrating ductal carcinoma benefit from postoperative radiotherapy: a population-based study[J]. Future Oncol, 2019,15(8):885-895. DOI: 10.2217/fon-2018-0495. [6] Qiu W, Yang Y, Sun S, et al.The role of postoperative radiotherapy and prognostic model in primary squamous cell carcinoma of parotid gland[J]. Front Oncol, 2020,10:618564. DOI: 10.3389/fonc.2020.618564. [7] Park YM, Kang MS, Kim DH, et al.Surgical extent and role of adjuvant radiotherapy of surgically resectable, low-grade parotid cancer[J]. Oral Oncol, 2020,107:104780. DOI: 10.1016/j.oraloncology.2020.104780. [8] Chan SA, Van Abel KM, Lewis JE, et al.Mucoepidermoid carcinoma of the parotid gland: twenty-year experience in treatment and outcomes[J]. Head Neck, 2021,43(9):2663-2671. DOI: 10.1002/hed.26735. [9] Jensen AD, Nikoghosyan A, Windemuth-Kieselbach C, et al.Combined treatment of malignant salivary gland tumours with intensity-modulated radiation therapy (IMRT) and carbon ions: COSMIC[J]. BMC Cancer, 2010,10:546. DOI: 10.1186/1471-2407-10-546. [10] Wong LS, McMahon J, Devine J, et al. Influence of close resection margins on local recurrence and disease-specific survival in oral and oropharyngeal carcinoma[J]. Br J Oral Maxillofac Surg, 2012,50(2):102-108. DOI: 10.1016/j.bjoms.2011.05.008. [11] Hosni A, Huang SH, Goldstein D, et al.Outcomes and prognostic factors for major salivary gland carcinoma following postoperative radiotherapy[J]. Oral Oncol, 2016,54:75-80. DOI: 10.1016/j.oraloncology.2015.11.023. [12] Lewis AG, Tong T, Maghami E.Diagnosis and management of malignant salivary gland tumors of the parotid gland[J]. Otolaryngol Clin North Am, 2016,49(2):343-380. DOI: 10.1016/j.otc.2015.11.001. [13] Westergaard-Nielsen M, Möller S, Godballe C, et al.Prognostic scoring models in parotid gland carcinoma[J]. Head Neck, 2021,43(7):2081-2090. DOI: 10.1002/hed.26672. [14] Kim YH, Chung WK, Jeong JU, et al.Evaluation of prognostic factors for the parotid cancer treated with surgery and postoperative radiotherapy[J]. Clin Exp Otorhinolaryngol, 2020,13(1):69-76. DOI: 10.21053/ceo.2019.00388. [15] Lima RA, Tavares MR, Dias FL, et al.Clinical prognostic factors in malignant parotid gland tumors[J]. Otolaryngol Head Neck Surg, 2005,133(5):702-708. DOI: 10.1016/j.otohns.2005.08.001. [16] Pohar S, Gay H, Rosenbaum P, et al.Malignant parotid tumors: presentation, clinical/pathologic prognostic factors, and treatment outcomes[J]. Int J Radiat Oncol Biol Phys, 2005,61(1):112-118. DOI: 10.1016/j.ijrobp.2004.04.052. [17] Bjørndal K, Krogdahl A, Therkildsen MH, et al.Salivary gland carcinoma in Denmark 1990-2005: outcome and prognostic factors. Results of the Danish Head and Neck Cancer Group (DAHANCA)[J]. Oral Oncol, 2012,48(2):179-185. DOI: 10.1016/j.oraloncology.2011.09.005. [18] Johnston ML, Huang SH, Waldron JN, et al. Salivary duct carcinoma: treatment, outcomes,patterns of failure[J]. Head Neck, 2016,38 Suppl 1:E820-826. DOI: 10.1002/hed.24107. [19] Tanvetyanon T, Fisher K, Caudell J, et al.Adjuvant chemoradiotherapy versus with radiotherapy alone for locally advanced salivary gland carcinoma among older patients[J]. Head Neck, 2016,38(6):863-870. DOI: 10.1002/hed.24172.