Radiotherapy in Larynx Squamous Cell Carcinoma is not Associated with an Increased Diagnosis of Second Primary Tumours

Aims: Larynx cancer is the most common form of head and neck squamous cell carcinoma (HNSCC). Radiotherapy is a major treatment modality and is implicated in the possible formation of second primary tumours (SPT). The aims of this retrospective study were to establish the incidence of SPTs and their correlation with previous radiotherapy and to establish overall survival and the SPT diagnostic time lag from the index tumour according to subtype as well as radiotherapy status. Materials and methods: In a retrospective study of 987 patients with larynx SCCs (1967-2004) associations between radiotherapy, diagnosis of SPTs, median SPT diagnostic time lag, disease-free survival and overall survival were analysed. Results: In total, 184 (18.6%) patients developed metachronous SPTs with an overall survival of 93.0 (standard error 6.8 months). One hundred and seventy (92.4%) underwent radiotherapy, whereas 14 (7.6%) patients were not exposed to radiotherapy. No significant increased incidence of SPT was shown in the radiotherapy group. A statistically non-significant increase in SPT diagnostic time lag trend was noted for both HNSCC SPTs (radiotherapy vs non-radiotherapy; 76.0 [standard error 6.7] vs 50.0 [standard error 23.0]) and lung SPTs (45.0 [standard error 12.1] vs 24.0 [standard error 4.9]) months. Conclusion: This study suggests that radiotherapy is not a risk for SPT induction; it may, however, neutralise a proportion of cancerised fields in the lung and head and neck areas without any significant benefit on overall survival.