Keloids are overgrown scar tissue that extends beyond the original wound boundaries. They are common after surgery, burns, piercings, or acne, especially in people with darker skin tones (Fitzpatrick types IV–VI). Radiotherapy is an effective adjuvant treatment to prevent keloid recurrence after surgical excision.
How It Works
Mechanism: Radiation damages DNA in rapidly dividing fibroblasts, reducing collagen overproduction and inhibiting keloid recurrence.
Timing: Usually starts within 24–48 hours after surgical removal of the keloid (the earlier, the better).
Modalities:
External beam radiotherapy (EBRT): Superficial X-rays or electrons (most common).
Brachytherapy: High-dose-rate (HDR) iridium-192 (used for irregular or large areas, e.g., earlobe).
Orthovoltage X-rays (50–150 kV) or electron beam (4–8 MeV) are preferred due to shallow penetration.
Standard Protocols (Evidence-Based)
Most widely used regimen (2023 consensus guidelines):
Total dose: 20 Gy in 4 fractions of 5 Gy each.
Schedule: Daily or every other day, starting <24–48 h post-excision.
Recurrence rate: 10–20% at 2 years (compared to 50–80% with surgery alone).
Alternative regimens:
12–18 Gy in 3–6 fractions (common in Asia).
Single fraction 13 Gy (brachytherapy, earlobe keloids).
Hypofractionated: 30 Gy in 6 fractions (older studies).
Efficacy (Meta-Analyses)
Flickinger (2011): Surgery + RT recurrence 19% vs surgery alone 60%.
van Leeuwen et al. (2018): Pooled recurrence 22% with RT vs 55% without.
Best results for earlobe keloids (<10% recurrence); worst for chest/presternal (>30%).
Side Effects
Acute: Erythema, dry desquamation (usually mild).
Late:
Hypo/hyperpigmentation (common in dark skin).
Telangiectasia.
Theoretical malignancy risk: Extremely low (<1 in 100,000). No confirmed radiation-induced cancers in keloid patients after >50 years of use (largest series: Ogawa et al., 30,000+ patients, zero malignancies).
Contraindicated in children <12 years, pregnancy, and collagen vascular diseases (lupus, scleroderma).
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