THE IMPACT OF RADIOTHERAPY COURSE LENGTH ON THE TREATMENT RESULTS OF NASOPHARYNGEAL CARCINOMA (NPC)
Abstract
Analyses were made among four radiotherapy schedules for NPC in order to determine whether there is an impact of radiotherapy course length on treatment results.
A series of 320 NPC patients were divided into four radiation treatment branches each with a schedule, this clinical trial was non- randomized. Radiotherapy comme length factor was considered with a derivative LQ model formula that biological effective dose (BED) = nd [ 1 + d/ (α/β)] - k(T - 28). The four branches were: 1. split - course 103 cases, with an intermediary rest of 3--4 weeks, mean total dose 70Gy/35fx, 73d, BED 51.6 Gy; 2. continuous 115 cases, 72Gy/36fx, 61d, BED 62.6 Gy; 3. hyperfroctionation I 52 cases, 1.5 Gy b.i.d., time interval (Ti)≥ 6 hr, 75Gy/49fx, 57d, BED 65.5Gy; 4. hyperfractionation K 50 cases, 1.2 Gy b.i.d., Ti≥6hr, 76Gy/60fx, 59d, BED 63.0 Gy.
Treatment results were compared with 1 -, and 3 - year loco- regional recurrent rotes, and 1 -, and 3 - year sm'vival rotes, and these rates were of a negative interrelation with prolonged course dtwation, but of a positive one with BED values. Continuous braneh was of a course mean 12 days shorter than the spilt-course one, its treatment results were nearly 10% higher in some subgroups ; and hyperfractionation branches were slightly better than continuous one.
A series of 320 NPC patients were divided into four radiation treatment branches each with a schedule, this clinical trial was non- randomized. Radiotherapy comme length factor was considered with a derivative LQ model formula that biological effective dose (BED) = nd [ 1 + d/ (α/β)] - k(T - 28). The four branches were: 1. split - course 103 cases, with an intermediary rest of 3--4 weeks, mean total dose 70Gy/35fx, 73d, BED 51.6 Gy; 2. continuous 115 cases, 72Gy/36fx, 61d, BED 62.6 Gy; 3. hyperfroctionation I 52 cases, 1.5 Gy b.i.d., time interval (Ti)≥ 6 hr, 75Gy/49fx, 57d, BED 65.5Gy; 4. hyperfractionation K 50 cases, 1.2 Gy b.i.d., Ti≥6hr, 76Gy/60fx, 59d, BED 63.0 Gy.
Treatment results were compared with 1 -, and 3 - year loco- regional recurrent rotes, and 1 -, and 3 - year sm'vival rotes, and these rates were of a negative interrelation with prolonged course dtwation, but of a positive one with BED values. Continuous braneh was of a course mean 12 days shorter than the spilt-course one, its treatment results were nearly 10% higher in some subgroups ; and hyperfractionation branches were slightly better than continuous one.