Hypofractionated radiation therapy for basal and squamous cell skin cancer: A meta-analysis

Abstract

PurposeTo characterize the cosmetic outcomes and local recurrence (LR) rates of various hypofractionated radiation therapy (RT) regimens for skin basal and squamous cell cancers (BCCs/SCCs). MethodsA PICOS/PRISMA/MOOSE selection protocol was performed to identify 344 articles published between 1985–2016 evaluating patients with T1–2 N0 SCCs/BCCs treated with definitive RT. Biologically equivalent doses with α/β=3 (BED3s) were calculated. The primary endpoint was post-treatment cosmesis. Mixed effects regression models were used to estimate weighted linear relationships between BED3 and cosmetic outcomes. ResultsA total of 21 studies were identified detailing the treatment of 9729 skin BCC/SCC patients, across seven countries, with external beam RT (n=9255) or brachytherapy (n=474). Median follow-up was 36months (range: 12–77). Median dose was 45Gy/11 fractions (interquartile range: 37.5Gy/6–55Gy/18) at 4Gy/fraction (interquartile range: 2.5–6Gy); most hypofractionated 18.75Gy/1. There was a trend to decreased “good” cosmesis with higher total dose: −3.4% “good” cosmesis/10Gy BED3, p=0.01. Similarly, there was a trend to increased “fair” cosmesis with higher dose: +3.8% “fair” cosmesis/10Gy BED3,p=0.006. At a BED3 of 100Gy, the expected rate of “good” cosmesis is 79% (95% confidence interval: 70%, 88%). Hypofractionated schedules produced similar cosmesis to conventionally fractionated schedules, at the same BED3. Fewer than 8% of patients experienced “poor” cosmesis, independent of dose or fractionation regimen. ConclusionHypofractionated RT has favorable cosmesis for patients with skin BCCs/SCCs. We recommend clinicians consider these commonly-used regimens, which all have BED3 of ∼100Gy: 50Gy/15 fractions, 36.75Gy/7 fractions, or 35Gy/5 fractions, as they result in “good” cosmesis in 80% of patients.