OBJECTIVETo investigate the clinical characteristics of second primary tumor of tongue after nasopharyngeal carcinoma (NPC) radiotherapy and the prognostic factors of patients.

METHODSFifty-three cases with second primary tumor of tongue after NPC radiotherapy, presenting to Cancer Centre, Sun Yat-sen University from Jan. 1st 1975 to Dec. 31st 2000 were analyzed retrospectively with regard to mortality and survival rate (Kaplan-Meier method); A multivariate analysis was performed in these patients with Cox proportional hazard model.

RESULTSForty of 53 patients died. Among them,37 died of second primary tumor of tongue, 2 of recurrence of NPC, 1 of perioperative period. The overall 5-year and 10-year survival rate of 51 patients receiving therapy were 41.64% and 35.69% respectively. The subsites of tumor were: tip 0, margin 26 (49.06%), ventral lateral 8 (15.09%) and dorsal aspect 19 (35.85%). Eighteen cases had recurrence of second primary tumor of tongue (33.96%) ; Six (11.32%) cases had clinical lymph node metastasis from second primary tumor of tongue and 3 (5.66%) had pathological lymph node metastasis; The univariate analysis showed the major prognostic factors influencing survival of these patients were tumor size, clinical TNM stage at presentation; Using multivariate analysis, risk factors that independently influence survival were clinical and pathological stage and the interval between two tumors.

CONCLUSIONSThe clinical and pathological stage and the interval between two tumors are the prognostic factors for second primary tumor of tongue after NPC radiotherapy.