Radiotherapy is not associated with an increased rate of Second Primary Tumours in Oral Squamous Carcinoma: A study of 370 patients

Oral Squamous Cell Carcinoma (OSCC) remains a public health scourge. Radiotherapy (RT) is a major treatment modality and has been implicated in possible formation of Second Primary Tumours (SPT). In a single centre retrospective study of 370 patients with OSCCs (1967-2004) associations between RT, diagnosis of SPTs, median SPT diagnostic time lag, Disease Free Survival (DFS) and overall survival (OS) were analysed. Sixty-eight (18.4%) patients developed metachronous SPTs. Two hundred and twenty patients (59.3%) underwent some form of RT whilst 151 (40.7%) patients were not exposed to RT. No significant increased incidence of SPTs was demonstrated in the RT group. No significant difference in SPT diagnostic time lag was noted amongst the groups. This study suggests that RT is neither a risk for SPT induction nor increases the relative diagnostic time delay of upper aero-digestive tract SPTs.