Case series report: radiation-induced oropharyngeal carcinoma

The incidence of radiation-induced secondary primary tumors (SPTs) is estimated to be between 1 and 20%. The oropharynx is not a common site for postradiotherapy head and neck SPTs. We describe the cases of eight patients, each with an SPT of the oropharynx. These developed after a long median latency of 17.7 years with each receiving two-dimensional radiation therapy and delivery of at least 5000 cGy per pharynx, except for one who was treated with IMRT. Tumor histological commonalities revealed squamous cell carcinoma p16 negative staining, local invasion, and limited lymphatic spread, with posterior wall of the oropharynx and the base of the tongue being the most common locations. Limited and challenging treatment options have been reported such as surgery, reirradiation, or clinical trials. Radiation-induced SP oropharyngeal carcinoma has unique clinical and pathological features. Patients with this disease have limited treatment options, which should be discussed in a multidisciplinary tumor board meeting. For this population, lifelong follow-up may help in early diagnosis and improve outcomes.