Do acute mucosal reactions lead to consequential late reactions in patients with head and neck cancer?

Background and purpose: The relationship between acute and late mucosal rea ctions remains ill defined but is of considerable relevance to efforts to p roduce therapeutic gains through the use of altered fractionation schemes a nd concurrent chemotherapy. We therefore investigated whether acute mucosal reactions in patients treated with an accelerated and a conventionally fra ctionated radiotherapy regime predicted the severity of late mucosal reacti ons. Patients and methods: The study population consisted of 191 patients random ised on a prospective trial comparing conventional fractionation at 2 Gy/fr action per day, 70 Gy over 47 days with an accelerated regimen of 59.4 Gy, 1.8 Gy BID over 24 days for Stage III-IV carcinoma of the head and neck. Ac ute and late mucosal reactions were scored according to RTOG/EORTC criteria and analyzed using multiple regression techniques. Results: The duration of time spent by patients at the acute confluent muco sitis grade 3 level was inversely related to the time to onset of the react ion for both fractionation schedules, Time to onset was more rapid for pati ents treated on the accelerated schedule but time spent at the reaction gra de did not differ significantly between the schedules. After correction for treatment and patient related factors, anatomical site (oral cavity/oropha rynx versus hypopharynx/larynx) and increasing duration of confluent mucosi tis emerged as independent predictors of the hazard of late mucosal reactio ns with the latter effect being more pronounced in the accelerated treatmen t arm. The expected reduction in late mucosal effects in the accelerated fr actionation arm, predicted by the LQ model for late effects was identified only in patients whose acute confluent mucosal reactions lasted less than 2 0 days. Conclusions: The presence of individual patient susceptibility factors that determine the severity of acute mucosal reactions is suggested. A link bet ween severe and prolonged acute reactions and the risk of developing late m ucosal reactions that is independent of biological dose, has also been foun d. Purpose designed prospective studies of these issues are necessary, (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.