ABSTRACT
<p><b>OBJECTIVE</b>To study the diagnosis and treatment of a second primary malignant tumor induced by previous radiotherapy.</p><p><b>METHODS</b>From March 1970 to March 1997, 108 nasopharyngeal cancer (NPC) patients who developed a second primary malignant tumor induced by radiotherapy were treated. There were squamous carcinoma 43 (39.8%), sarcoma 26 (24.1%), malignant fibrous histiocytoma 14 (13.0%), adenoid cystic carcinoma 12 (11.1%), thyroid papillary adenocarcinoma 8 (7.4%) and malignant melanoma 5 (4.6%). Fifty patients underwent operation, 32 received radiotherapy, 18 received chemotherapy and 8 received operation combined with chemotherapy.</p><p><b>RESULTS</b>The 3- and 5-year tumor-free survival rates were 64.0% and 36.0% in the operation group. They were 34.4% and 18.8% in the radiotherapy group.</p><p><b>CONCLUSION</b>Surgery, if not contra-indicated, is the first choice for the second primary malignant tumor induced by radiotherapy. Aggressive treatment for these patients is, hence, indicated clinically.</p>