A Cochrane review [Abstract] 1 included 9 studies with a total of 8228 subjects. The women were highly selected: tumours were node negative and 89.9 % were smaller than 3 cm. Data for local recurrence and breast appearance were not available in a form which could be combined. There were no difference between delivering radiation therapy in larger amounts each day but over fewer days (unconventional fractionation: fraction size greater than 2 Gy) and conventional fractionation (2 Gy per fraction) regimes in local-recurrence free survival, breast appearance,or survival at 10 years; high quality evidence (table T1). Altered fraction size was associated with less patient-reported and physician-reported fatigue at six months (1 trial, n=287). There was no difference for patient-reported outcomes of physical, functional, emotional, or social well-being.
| Outcome | Relative effect(95% CI) | Risk with conventionally fractionated radiation therapy | Risk with hypofractionated radiation therapy (95% CI) | №of participants(studies) |
|---|---|---|---|---|
| Local recurrence-free survival at 10 years | HR 0.94(0.77 to 1.15) | 70 / 1000 | 66 / 1000(54 to 80) | 7095(4) |
| Cosmetic appearancefollow-up: 42 months-12 years | RR 0.90(0.81 to 1.01) | 311 / 1000 | 280 / 1000(252 to 314) | 2103(4) |
| Mortality at 10 years | HR 0.91(0.80 to 1.03) | 166 / 1000 | 153 / 1000(135 to 171) | 5685(3) |
| Breast cancer-specific survival (BC-SS) at 10 years | HR 0.91(0.78 to 1.06) | 123 / 1000 | 113 / 1000(98 to 130) | 5685(3) |
| Late subcutaneous toxicity,follow-up: 6 years | RR 0.93(0.83 to 1.05) | 4 / 1000 | 4 / 1000(3 to 4) | 5130(4) |
Comment: The quality of evidence is downgraded by indirectness (follow up of five years is not adequate to detect differences in breast cancer mortality).
Primary/Secondary Keywords