Surgery Followed by Postoperative Radiation Therapy for Minor Salivary Gland Tumors

Abstract

Purpose/Objective(s)Minor salivary gland cancers account for roughly 2-3% of all head and neck tumors, and as result there is a limited number of studies on the subject matter. Thus, we conducted a retrospective review of a single institution's experience on a large cohort of minor salivary tumors treated with surgery and post-operative radiation therapy with the goal of identifying factors that influence treatment outcome.Materials/MethodsBetween 2/90 and 12/10, 98 patients with cancer of the minor salivary glands, with a median age of 52 years at diagnosis, were treated at our center. Sites involved were: sinus/nasopharynx/nasal cavity (27), oral cavity (38) and oropharynx (17), and other (16). The following histologies were seen: adenoid cystic (46), mucoepidermoid (27), adenocarcinoma (21), myoepithelial (1), salivary duct (1), acinic cell (1), and poorly differentiated carcinoma. There were (1) TX, (23) T1, (28) T2, (12) T3, and (34) T4 tumors. Among these, 27 patients had nodal involvement. Sixteen patients received chemotherapy, the majority of which were platinum-based. Twelve patients in this cohort had recurrent disease after one prior surgery. Median radiation dose was 63Gy (range 12-70 Gy). Margin status was as follows: 44 positive, 14 close, 31 negative and 9 with missing margin information. 16 patients received chemotherapy. Local control (LC), loco-regional control (LRC), distant metastasis-free (DMF) rates were analyzed using the Competing Risk analysis. Kaplan-Meier method was used to generate overall survival (OS) curves.ResultsWith a median follow-up of 87 months, the 5- and 10-year LC and LRC rates were 87.9% vs. 83% and 80.5% vs. 73.7%, respectively. Freedom from distant metastasis at 5- and 10- years were 83% and 63%, respectively. The median OS was 19.6 years corresponding to a 5- and 10-year OS of 82% and 58%, respectively. On univariate analysis T stage [HR 1.69, CI 1.1-2.6, p=0.01] and adenocarcinoma histology (HR 3.378, CI 1.39 - 8.19, p=0.007) were associated with increased locoregional failure. T stage (p=0.03) and adenocarcinoma (p=0.02) histology also predicted for increased local failure. N-stage, recurrent disease, margin status, KPS, and radiation dose were not predictive for local or locoregional failure. Most common acute toxicities were dermatitis, mucositis, xerostomia, dysphagia, and fatigue. One patient lost vision as a result of radiation therapy.ConclusionsIn this large cohort of minor salivary gland tumors treated with surgery followed by post-operative radiation therapy, excellent local and locoregional control rates were observed. Higher T-stage and adenocarcinoma histologies were the most significant negative prognostic factors. Further studies on maximizing tumor control for this group of patients are warranted. Purpose/Objective(s)Minor salivary gland cancers account for roughly 2-3% of all head and neck tumors, and as result there is a limited number of studies on the subject matter. Thus, we conducted a retrospective review of a single institution's experience on a large cohort of minor salivary tumors treated with surgery and post-operative radiation therapy with the goal of identifying factors that influence treatment outcome. Minor salivary gland cancers account for roughly 2-3% of all head and neck tumors, and as result there is a limited number of studies on the subject matter. Thus, we conducted a retrospective review of a single institution's experience on a large cohort of minor salivary tumors treated with surgery and post-operative radiation therapy with the goal of identifying factors that influence treatment outcome. Materials/MethodsBetween 2/90 and 12/10, 98 patients with cancer of the minor salivary glands, with a median age of 52 years at diagnosis, were treated at our center. Sites involved were: sinus/nasopharynx/nasal cavity (27), oral cavity (38) and oropharynx (17), and other (16). The following histologies were seen: adenoid cystic (46), mucoepidermoid (27), adenocarcinoma (21), myoepithelial (1), salivary duct (1), acinic cell (1), and poorly differentiated carcinoma. There were (1) TX, (23) T1, (28) T2, (12) T3, and (34) T4 tumors. Among these, 27 patients had nodal involvement. Sixteen patients received chemotherapy, the majority of which were platinum-based. Twelve patients in this cohort had recurrent disease after one prior surgery. Median radiation dose was 63Gy (range 12-70 Gy). Margin status was as follows: 44 positive, 14 close, 31 negative and 9 with missing margin information. 16 patients received chemotherapy. Local control (LC), loco-regional control (LRC), distant metastasis-free (DMF) rates were analyzed using the Competing Risk analysis. Kaplan-Meier method was used to generate overall survival (OS) curves. Between 2/90 and 12/10, 98 patients with cancer of the minor salivary glands, with a median age of 52 years at diagnosis, were treated at our center. Sites involved were: sinus/nasopharynx/nasal cavity (27), oral cavity (38) and oropharynx (17), and other (16). The following histologies were seen: adenoid cystic (46), mucoepidermoid (27), adenocarcinoma (21), myoepithelial (1), salivary duct (1), acinic cell (1), and poorly differentiated carcinoma. There were (1) TX, (23) T1, (28) T2, (12) T3, and (34) T4 tumors. Among these, 27 patients had nodal involvement. Sixteen patients received chemotherapy, the majority of which were platinum-based. Twelve patients in this cohort had recurrent disease after one prior surgery. Median radiation dose was 63Gy (range 12-70 Gy). Margin status was as follows: 44 positive, 14 close, 31 negative and 9 with missing margin information. 16 patients received chemotherapy. Local control (LC), loco-regional control (LRC), distant metastasis-free (DMF) rates were analyzed using the Competing Risk analysis. Kaplan-Meier method was used to generate overall survival (OS) curves. ResultsWith a median follow-up of 87 months, the 5- and 10-year LC and LRC rates were 87.9% vs. 83% and 80.5% vs. 73.7%, respectively. Freedom from distant metastasis at 5- and 10- years were 83% and 63%, respectively. The median OS was 19.6 years corresponding to a 5- and 10-year OS of 82% and 58%, respectively. On univariate analysis T stage [HR 1.69, CI 1.1-2.6, p=0.01] and adenocarcinoma histology (HR 3.378, CI 1.39 - 8.19, p=0.007) were associated with increased locoregional failure. T stage (p=0.03) and adenocarcinoma (p=0.02) histology also predicted for increased local failure. N-stage, recurrent disease, margin status, KPS, and radiation dose were not predictive for local or locoregional failure. Most common acute toxicities were dermatitis, mucositis, xerostomia, dysphagia, and fatigue. One patient lost vision as a result of radiation therapy. With a median follow-up of 87 months, the 5- and 10-year LC and LRC rates were 87.9% vs. 83% and 80.5% vs. 73.7%, respectively. Freedom from distant metastasis at 5- and 10- years were 83% and 63%, respectively. The median OS was 19.6 years corresponding to a 5- and 10-year OS of 82% and 58%, respectively. On univariate analysis T stage [HR 1.69, CI 1.1-2.6, p=0.01] and adenocarcinoma histology (HR 3.378, CI 1.39 - 8.19, p=0.007) were associated with increased locoregional failure. T stage (p=0.03) and adenocarcinoma (p=0.02) histology also predicted for increased local failure. N-stage, recurrent disease, margin status, KPS, and radiation dose were not predictive for local or locoregional failure. Most common acute toxicities were dermatitis, mucositis, xerostomia, dysphagia, and fatigue. One patient lost vision as a result of radiation therapy. ConclusionsIn this large cohort of minor salivary gland tumors treated with surgery followed by post-operative radiation therapy, excellent local and locoregional control rates were observed. Higher T-stage and adenocarcinoma histologies were the most significant negative prognostic factors. Further studies on maximizing tumor control for this group of patients are warranted. In this large cohort of minor salivary gland tumors treated with surgery followed by post-operative radiation therapy, excellent local and locoregional control rates were observed. Higher T-stage and adenocarcinoma histologies were the most significant negative prognostic factors. Further studies on maximizing tumor control for this group of patients are warranted.