Stereotactic Body Radiotherapy (SBRT) for the Palliation of Unirradiated Mucosal Head and Neck Tumors

Abstract

We report the treatment outcomes of palliative SBRT to primary mucosal unirradiated head and neck cancer (HNC) patients that were ineligible to receive conventional radiation therapy (RT) MATERIALS/METHODS: We retrospectively reviewed patients with primary mucosal HNC treated with SBRT from 2011-2020. Patients with histologies other than squamous cell carcinoma, with primary skin disease or with recurrent tumors were excluded. SBRT was used in this cohort of patients because of associated comorbidities that precluded full course RT. All patients were followed regularly with clinical examination and imaging. The endpoints were local failure (LF) defined as recurrence of tumor at the irradiated site, overall survival (OS), acute and late grade 3 and 4 toxicity.Sixty patients with a median age of 81 years were treated with SBRT technique. The median follow-up was 7.8 months. 8(13%), 38(63%), 13(22%) and 1(2%) were ECOG 1, 2, 3 and 4, performance status respectively. Oral cavity was the most common cancer site in our cohort (60%, 36 patients), followed by oropharyngeal cancer (15%, 9 patients), larynx (7%, 4 patients), hypopharynx (5%, 3 patients), parotid cancer (5%, 3 patients), unknown primary (5%, 3 patients) and nasal cavity/sinonasal cancer (3%, 2 patients). Tx-2 and T3-4 lesions were found in 18(30%) and 42(70%), respectively, while 32(53%) and 28(47%) were staged N0-1, N2-3, respectively. GTV was prescribed to 45 Gy in 5 fractions, most commonly used (55%), followed by 40 Gy in 5 fractions (37%). A high dose CTV was not used around GTV although an elective nodal volume of 25 Gy in 5 fractions was also used. 52 patients were treated twice a week completed in 13-20 days, 2 patients completed their treatments in 9 and 10 days, while 5 patients over 21-28 days. The cumulative incidence of LF at 6 and 12 months was 5.3% (95% CI 1.4-13.3) and 12.4% (95% CI 4.9-23.7), respectively. The median (OS) was 9.2 months. The 6 and 12 month OS rates were 67.9% (95% CI 56.6-81.4) and 41.4% (95% CI 29.2-58.7), respectively. Cancer was the cause of death in 12 patients (38%), while 20 deaths (62%) were not related to malignant disease. Acute G3 toxicity was observed in 23 patients, including G3 mucositis in 19 patients, G3 dermatitis in 2 patients and G3 dysphagia in 2 patients. Five patients developed G3+ late toxicity, including osteoradionecrosis (n = 3), soft tissue supraglottic ulceration (n = 1) and trismus (n = 1). Four of these 5 patients did not have evidence of concurrent local recurrence.HN SBRT has been largely reported in the re-irradiation setting, however, SBRT may have greater utility in the palliative management of previously untreated HNC patients. Despite the advanced age and performance status noted in this group of patients with mucosal SCC of the head and neck, who were not eligible for conventional RT, SBRT was associated with low local failure rates and reasonable toxicity profile. A randomized controlled trial is warranted to confirm the efficacy of HN SBRT in this setting.