Second Primary Malignancies in Pediatric and Adolescent Nasopharyngeal Carcinoma Survivors: Experience of a Single-center

OBJECTIVE The aim of this study is to investigate the incidence and clinicopathologic characteristics of second primary malignancies (SPMs) in pediatric and adolescent nasopharyngeal carcinoma (NPC) survivors from the point of patients' age, emergence time, location and histopathology. METHODS Medical reports of pediatric NPC patients (patients at or under the age of 19) treated between 1990 and 2017 and followed till the end 2020 were reviewed. SPMs are classified depending on the organ, histopathology, location (whether in or out of the radiation field). Additionally time period between NPC treatment and diagnosis of second primaries are recorded. RESULTS The median age of the 108 patients at diagnosis was 15 years (5-19 years). The male-to-female ratio was 2.1. The median follow-up was 118 months (3-332 months). Eight patients developed 9 second malignancies (one patient with two SPMs). Eight of SPMs were in the radiation field. SPMs developed at a median of 15 years (5-26 years) after the conclusion of the primary treatment. Among patients, whose malignancy developed in the irradiation field 6 were treated primarily with complete surgical resection and 3 of them died because of SPM. CONCLUSION Incidences of SPMs have been increasing in parallel with the increase in life expectancy of pediatric and adolescent NPC survivors. Due to relatively high numbers of SPMs, pediatric/adult nasopharyngeal cancer survivors should be followed regularly not only for recurrences and long term morbidities but also for second malignancies which may be treated with curative surgeries and additional treatments when diagnosed early. The patient follow-up should continue and patients should be evaluated comprehensively, taking into account cancers outside the irradiation field. Since the most of the SPMs develops in the irradiation field, prospective clinical studies investigating dose reduction in the treatment of pediatric NPC should be considered and evaluated with further prospective trials.