Second malignant tumors after treatment of nasopharyngeal carcinoma: four case reports and literature review.

The purpose of this study was to identify the histopathology, location, and latency interval for the development of second malignant tumors (SMT) after successful treatment for nasopharyngeal carcinoma (NPC). Of 55 patients, four developed SMT after successful treatment of NPC in a single institutional series for an incidence of 7%. An additional 31 patients with SMT after treatment for NPC were identified from the literature. At minimum, all patients were treated with radiotherapy to the primary site. The histopathology of SMT included sarcoma (69%), squamous cell carcinoma (17%), adenocarcinoma (6%), meningioma (6%), and lymphoma (3%). SMT occurred at various sites in the head and neck, but most (51%) arose in the sinonasal cavity. For the entire group, the mean latency interval between treatment for NPC and the development of SMT was 11.8 years. These findings indicate that the development of SMT in patients achieving long-term survival after treatment for NPC may be radiation induced. Long-term follow-up for these patients is important to assess for this potentially late complication.