Characteristics and outcome of radiation and chemotherapy-related mucoepidermoid carcinoma of the salivary glands

Background: Mucoepidermoid carcinoma (MEC) of the salivary glands has been reported to occur in patients previously treated with chemotherapy and/or radiation. The purpose of our study is to review the patient, tumor, and treatment characteristics of patients who develop a treatment-related MEC. Procedure: A PubMed search of English language articles was performed using the keywords and MeSH terms: mucoepidermoid, salivary gland, radiation-induced, second malignancy, radiotherapy, and chemotherapy. Results: The search yielded 23 articles describing 58 patients who received chemotherapy and/or radiotherapy (RT) and subsequently developed MEC. The most common initial diagnoses were acute lymphoblastic leukemia (n=18), acne (n=9), and Hodgkin lymphoma (n=6). Patients were divided into three groups according to chemotherapy and RT treatment: chemotherapy alone (n=14), RT alone (n=14), or chemotherapy and RT (n=30). The parotid gland was the most common site for secondary MEC. Latent time (LT) to development of MEC from initial tumor treatment was significantly shorter in the patients treated with chemotherapy±RT versus RT alone (7.9 years vs. 27.2 years, P<0.01). The most common treatment for MEC was surgery alone followed by surgery and postoperative RT. The 2- and 5-year overall survival rates were 98% and 93.4% while the 2- and 5-year locoregional control rates were 97.7% and 92.5%, respectively. There was no difference in survival or locoregional control between groups exposed to RT alone, chemotherapy alone, or chemotherapy with RT for the initial tumor. Conclusion: Radiation and chemotherapy-related MEC has an excellent prognosis.