Initial experience with a practical hyperfractionated accelerated radiotherapy regimen

• Published in: International journal of radiation oncology, biology, physics Vol. 21; no. 5; pp. 1275 - 1281
• Main Authors: Herskovic, Arnold, Orton, Colin, Seyedsadr, Mahmoud, Lattin, Paul, Kraut, Michael, Han, Ihn, Han, Sue, Ahmad, Khursid, Holt, Jennifer
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.10.1991; Elsevier
• Subjects: Accelerated hyperfractionation; Aged; Biological and medical sciences; Carcinoma, Bronchogenic - radiotherapy; Carcinoma, Small Cell - radiotherapy; Diseases of the respiratory system; Female; Humans; L-Q model; Lung cancer; Lung Neoplasms - radiotherapy; Male; Medical sciences; Middle Aged; Models, Biological; Models, Theoretical; Radiation therapy; Radiotherapy - methods; Radiotherapy Dosage; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Accelerated hyperfractionation; Radiation therapy; L-Q model; Lung cancer; Carcinoma; Radiotherapy; Respiratory disease; Lung; Fractionated dose
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/0360-3016(91)90286-D

This paper presents early results of a trial of a three-fractions-per-day (TID) regimen that is more convenient to schedule than the Continuous Hyperfractionated Accelerated Radiotherapy (CHART) protocol currently being tested in Europe. The treatment schedule used in the CHART regimen has been modified from 36 fractions of 1.5 Gy TID in 12 days to 72 fractions of 1.1 Gy in 24 treatment days, with all fractions delivered during normal working hours. With no weekend treatments, the entire course of radiotherapy is completed in less than 5 weeks. The doses used were determined using the L-Q model, with correction for incomplete repair between fractions and for accelerated repopulation of cancer cells. Comparison with historical controls shows statistically significant improvements both in CR rates for the primary tumor and in acute toxicity, as measured by reduced treatment interruptions. L-Q model calculations predict that, compared to the highest dose achieved in previous studies without exceeding tolerance, we are able to obtain a 12% increase in bioeffect dose to the primary tumor due to accelerating the treatment. An analysis of the potential tumoricidal effectiveness of this new treatment regimen shows that it should be better than several other accelerated fractionation schedules being tested for all values of T ot. For short T pot times, the advantage may be as much as one log cell kill, corresponding to a 10–15% potential improvement in local control.