Postoperative Radiotherapy for Parotid Gland Malignancy / 대한방사선종양학회지

PURPOSE: The aim of this study was to evaluate the clinical results of postoperative radiotherapy for parotid gland malignancy, and determine prognostic factors for locoregional control and survival. MATERIALS AND METHODS: Between 1980 and 2002, 130 patients with parotid malignancy were registered in the database of the Department of Radiation Oncology, Seoul National University Hospital. The subjects of this analysis were the 72 of these 130 patients who underwent postoperative irradiation. There were 42 males and 30 females, with a median age of 46.5 years. The most common histological type was a mucoepidermoid carcinoma. There were 6, 23, 23 and 20 patients in Stages I, II, III and IV, respectively. The median dose to the tumor bed was 60 Gy, with a median fraction size of 1.8 Gy. RESULTS: The overall 5 and 10 year survival rates were 85 and 76%, respectively. The five-year locoregional control rate was 85%, which reached a plateau phase after 6 years. Sex and histological type were found to be statistically significant for overall survival from a multivariate analysis. No other factors, including age, facial nerve palsy and stage, were related to overall survival. For locoregional control, nodal involvement and positive resection margin were associated with poor local control. Histological type, tumor size, perineural invasion and type of surgery were not significant for locoregional control. CONCLUSION: A high survival rate of parotid gland malignancies, with surgery and postoperative radiotherapy, was confirmed. Sex and histological type were significant prognostic factors for overall survival. Nodal involvement and a positive resection margin were associated with poor locoregional control.

Postoperative Radiotherapy for Parotid Gland Malignancy / 대한방사선종양학회지

PURPOSE: The aim of this study was to evaluate the clinical results of postoperative radiotherapy for parotid gland malignancy, and determine prognostic factors for locoregional control and survival. MATERIALS AND METHODS: Between 1980 and 2002, 130 patients with parotid malignancy were registered in the database of the Department of Radiation Oncology, Seoul National University Hospital. The subjects of this analysis were the 72 of these 130 patients who underwent postoperative irradiation. There were 42 males and 30 females, with a median age of 46.5 years. The most common histological type was a mucoepidermoid carcinoma. There were 6, 23, 23 and 20 patients in Stages I, II, III and IV, respectively. The median dose to the tumor bed was 60 Gy, with a median fraction size of 1.8 Gy. RESULTS: The overall 5 and 10 year survival rates were 85 and 76%, respectively. The five-year locoregional control rate was 85%, which reached a plateau phase after 6 years. Sex and histological type were found to be statistically significant for overall survival from a multivariate analysis. No other factors, including age, facial nerve palsy and stage, were related to overall survival. For locoregional control, nodal involvement and positive resection margin were associated with poor local control. Histological type, tumor size, perineural invasion and type of surgery were not significant for locoregional control. CONCLUSION: A high survival rate of parotid gland malignancies, with surgery and postoperative radiotherapy, was confirmed. Sex and histological type were significant prognostic factors for overall survival. Nodal involvement and a positive resection margin were associated with poor locoregional control.

Postoperative Radiotherapy in Malignant Tumors of the Parotid Gland / 대한방사선종양학회지

PURPOSE: This study was performed to analyze the factors affecting local control in malignant tumors of the parotid gland treated with surgery and postoperative radiation. MATERIALS AND METHODS: Twenty-six patients were treated for malignant tumors of the parotid gland from 1986 to 1995 at Department of Therapeutic Radiology, Chonnam University Hospital. Age of the patients ranged from 14 to 72 years (median : 55 years). Histologically 10 patients of mucoepidermoid carcinoma, 7 of squamous cell carcinoma, 4 of acinic cell carcinoma, 4 of adenoid cystic carcinoma and 1 of adenocarcinoma were treated. Total parotidectomy was performd in 15 of 26 patients, superficial in 7, subtotal in 4. Facial nerve was sacrificed in 5 patients. Postoperatively 4 patients had residual disease, 4 had positive resection margin. Radiation was delivered through an ipsilateral wedged pair of photon in 11 patients. High energy electron beam was mixed with photon in 15 patients. Electron beam dose ranged from 900 cGy to 3800 cGy (median : 1760 cGy). Total radiation dose ranged from 5000 cGy to 7560 cGy (median : 6020 cGy). Minimum follow-up period was 2 years. Local control and survival rate were calculated using Kaplan-Meier method. Generalized Wilcoxon test and Cox proportional hazard model were used to test factors affecting local control. RESULTS: Five (19%) of 26 patients had local recurrence. Five year local control rate was 77%. Overall five year survival rate was 70%. Sex, age, tumor size, surgical involvement of cervical lymph node, involvement of resection margin, surgical invasion of nerve, and total dose were analyzed as suggested factors affecting local control rate. Among them patients with tumor size less than 4 cm (p=0.002) and negative resection margin (p= 0.011) were associated with better local control rates in univariate analysis.Multivariate analysis showed only tumor size factor is associated with local control rate (p=0.022). CONCLUSION: This study suggested that tumor size is important in local control of malignant tumors of parotid gland.