Randomized trial of breast irradiation schedules after lumpectomy for women with lymph node-negative breast cancer. Five year results of a randomized trial comparing hyperfractionated to conventional radiotherapy over four weeks in locally advanced head and neck cancer. A Radiation Therapy Oncology Group (RTOG) phase III randomized study to compare hyperfractionation and two variants of accelerated fractionation to standard fractionation radiotherapy for head and neck squamous cell carcinomas: first report of RTOG 9003.
Breast irradiation after lumpectomy is an integral component of breast-conserving therapy that reduces the local recurrence of breast cancer. Because an optimal fractionation schedule (radiation dose given in a specified number of fractions or treatment sessions over a defined time) for breast irradiation has not been uniformly accepted, we examined whether a 22-day fractionation schedule was as effective as the more traditional 35-day schedule in reducing recurrence.
                Women with invasive breast cancer who were treated by lumpectomy and had pathologically clear resection margins and negative axillary lymph nodes were randomly assigned to receive whole breast irradiation of 42.5 Gy in 16 fractions over 22 days (short arm) or whole breast irradiation of 50 Gy in 25 fractions over 35 days (long arm). The primary outcome was local recurrence of invasive breast cancer in the treated breast. Secondary outcomes included cosmetic outcome, assessed with the European Organisation for Research and Treatment of Cancer (EORTC) Cosmetic Rating System. All statistical tests were two-sided.
                From April 1993 through September 1996, 1234 women were randomly assigned to treatment, 622 to the short arm and 612 to the long arm. Median follow-up was 69 months. Five-year local recurrence-free survival was 97.2% in the short arm and 96.8% in the long arm (absolute difference = 0.4%, 95% confidence interval [CI] = -1.5% to 2.4%). No difference in disease-free or overall survival rates was detected between study arms. The percentage of patients with an excellent or good global cosmetic outcome at 3 years was 76.8% in the short arm and 77.0% in the long arm; the corresponding data at 5 years were 76.8% and 77.4%, respectively (absolute difference = -0.6%, 95% CI = -6.5% to 5.5%).
                The more convenient 22-day fractionation schedule appears to be an acceptable alternative to the 35-day schedule. Fractionation strategies delivered over 4 weeks are of clinical and radiobiological interest because treatment is completed before radiotherapy (RT) induced clonogen proliferation commences in earnest approximately 3 to 4 weeks into a course of RT. We wished to test the clinical hypothesis that an increased total dose delivered over 4 weeks with smaller than standard doses per fraction in locally advanced squamous cell carcinoma (SCC) may result in relative protection of late responding tissues and an increased tumor control compared to a conventional daily course in the same overall time.
                Between 1988 and 1995 a randomized controlled trial employing RT alone was undertaken at the Princess Margaret Hospital that included 331 eligible patients with T3 or T4 N0 or any N-positive oropharynx, hypopharynx, or larynx primary SCC. RT was randomly assigned to one of two 4 week schedules, either 51 Gy in 20 equal daily fractions, termed conventional fractionation (CF), or 58 Gy in 40 equal fractions given twice per day as a hyperfractionated (HF) experimental arm.
                The 5-year local relapse rate was reduced in the HF (41%) compared to the CF arm (49%). This difference was marginally not significant (p=0.082) when the effect was not adjusted. When the effect of the treatment was adjusted by Cox model for clinical factors that included N-category, ECOG performance status, site of disease, T-category, age, hemoglobin, and gender the HF achieved a significant effect (p=0.02). Survival (40% vs. 30%) was also improved with HF compared to CF arm. This difference was only marginally not significant (p=0.069) but again achieved statistical significance when the model was adjusted for clinical factors (p=0.01). Similar results were observed for disease free survival. Although reversible acute toxicity was increased with HF, the overall 5-year rate of grade 3 and 4 late toxicity for the CF was 10.5% compared to 7.7% in the higher dose HF arm.
                HF delivered in 4 weeks permits enhanced RT doses achieving improved tumor control, without increased late toxicity, compared to daily fractionated radiotherapy in the same overall time. The optimal fractionation schedule for radiotherapy of head and neck cancer has been controversial. The objective of this randomized trial was to test the efficacy of hyperfractionation and two types of accelerated fractionation individually against standard fractionation.
                Patients with locally advanced head and neck cancer were randomly assigned to receive radiotherapy delivered with: 1) standard fractionation at 2 Gy/fraction/day, 5 days/week, to 70 Gy/35 fractions/7 weeks; 2) hyperfractionation at 1. 2 Gy/fraction, twice daily, 5 days/week to 81.6 Gy/68 fractions/7 weeks; 3) accelerated fractionation with split at 1.6 Gy/fraction, twice daily, 5 days/week, to 67.2 Gy/42 fractions/6 weeks including a 2-week rest after 38.4 Gy; or 4) accelerated fractionation with concomitant boost at 1.8 Gy/fraction/day, 5 days/week and 1.5 Gy/fraction/day to a boost field as a second daily treatment for the last 12 treatment days to 72 Gy/42 fractions/6 weeks. Of the 1113 patients entered, 1073 patients were analyzable for outcome. The median follow-up was 23 months for all analyzable patients and 41.2 months for patients alive.
                Patients treated with hyperfractionation and accelerated fractionation with concomitant boost had significantly better local-regional control (p = 0.045 and p = 0.050 respectively) than those treated with standard fractionation. There was also a trend toward improved disease-free survival (p = 0.067 and p = 0.054 respectively) although the difference in overall survival was not significant. Patients treated with accelerated fractionation with split had similar outcome to those treated with standard fractionation. All three altered fractionation groups had significantly greater acute side effects compared to standard fractionation. However, there was no significant increase of late effects.
                Hyperfractionation and accelerated fractionation with concomitant boost are more efficacious than standard fractionation for locally advanced head and neck cancer. Acute but not late effects are also increased.
Two new studies have been published since the last version of the review, altering our conclusions. We have evidence from four low to medium quality randomised trials that using unconventional fractionation regimens (greater than 2 Gy per fraction) does not affect local recurrence, is associated with decreased acute toxicity and does not seem to affect breast appearance or late toxicity for selected women treated with breast conserving therapy. These are mostly women with node negative tumours smaller than 3 cm and negative pathological margins. Long-term follow up (> 5 years) is available for a small proportion of the patients randomised. Longer follow up is required for a more complete assessment of the effect of altered fractionation.