Short-course radiation for palliation of squamous cell carcinoma of an unknown primary of the head and neck.

62 Background: The purpose of this study was to examine the treatment patterns used for palliative radiotherapy for squamous cell carcinoma of an unknown primary of the head and neck and to compare the acute toxicity and tumor response for these patients for the most common dose-fractionation regimens. Methods: Patients with biopsy-proven squamous cell carcinoma of an unknown primary with cervical lymphadenopathy were included who were treated with radiation therapy with palliative intent at a single institution between 1966 and 2015 (N = 45). Chart abstraction was performed on the radiation therapy records and follow-up visit notes. Results: Most patients presented with N3 disease (32/45, 71%), with symptoms of pain (19/45, 42%), or with difficulty swallowing (12/45, 27%). Patients were most commonly treated with 20 Gy in 2 fractions (13/45, 29%) or 30 Gy in 10 fractions (13/45, 29%). Toxicity was mild regardless of dose-fractionation, with only 6 patients experiencing dysphagia and 1 having a pulmonary embolus. Most patients had a partial nodal response during the radiation course (25/45, 56%), and partial symptom response by the first followup (17/33, 52%). Results were similar for 20 Gy and 30 Gy courses. Median survival was approximately 5 months and did not differ by radiation course. Conclusions: Patients treated with dose-fractionations of 20 Gy in 2 weekly treatments or 30 Gy in 10 fractions had minimal toxicity. Most patients had an excellent response in nodal size during radiation and nearly all had symptomatic response within the first month of follow. Patients with advanced disease of the head and neck may have a surprising durability of response with even a short course of palliative radiation therapy.