Statistical evaluation of a total dose-dose rate relationship in oral tongue cancer 192 Ir implants

A statistical tool has been made by us on 55 patients treated for oral tongue cancer with unique 192 Ir interstitial curietherapy in Brescia from 1973 to 1981. Our aim was to verify a simple analytical relationship proposed and adopted by us for oral tongue cancer implants in order to reduce the total dose with increasing dose rates and to calculate the equivalent total dose when referred to 0.357 Gy/hr. Recurrences and radionecroses are studied in a variance analysis, distinguishing according to stage and total dose; within the dose rate range used, a highly significant difference in radionecrosis rate (P less than 0.005) confirms our isoeffect relationship.