Eye and skin
Keloids and hypertrophic scars
Raised, expanding scars after surgery or injury that post-excision radiation stops from regrowing.
Definition
Keloids are benign fibroproliferative scars that grow beyond the boundaries of the original wound, invading surrounding normal skin; hypertrophic scars stay within the wound margins but remain raised, red, and symptomatic. They cause pain, itching, burning, and cosmetic deformity, and occur most often on the earlobes, jawline, chest, shoulder, and deltoid regions, with higher rates in patients with darker skin.
How radiation treats it
Radiation, delivered within 24–48 hours after surgical excision, inhibits the proliferating fibroblasts and endothelial cells in the fresh wound bed before they can re-lay the excessive collagen matrix. The wound then heals with a flatter, softer, more normal scar. Combined excision plus radiation reduces keloid recurrence from roughly 50–80% with surgery alone to about 10–25%.
Side effects
- Acute: mild redness and dryness of the treated skin, resolving in a few weeks.
- Temporary or occasionally lasting hypopigmentation in the treated area, which is a notable cosmetic consideration in darker skin.
- Theoretical long-term skin cancer risk at the treated site is extremely low at these doses but influences the decision for young patients and areas of sun-exposed skin.
Simulation process
Most cases need no CT — orthovoltage (50–150 kV) photons or low-energy electrons (4–9 MeV) with bolus are planned on the treatment machine or simple simulator images. The excision bed plus a 2–3 mm margin is outlined with radiopaque wire, and lead or custom shielding protects surrounding skin. The lesion must be traceable to the original wound, so marks are placed directly on the fresh (closed) wound at the time of simulation, ideally the same day as excision.
Treatment process
Typical regimens deliver 10–20 Gy total — for example, three fractions of 5 Gy or five fractions of 3 Gy over one to two weeks — beginning within 24–48 hours after excision. The shallow beams treat only the skin surface. Silicone sheeting and pressure earrings complement radiation for earlobe keloids. Patients are followed at one to three months to confirm flat, quiescent healing.
Key takeaways for students
- Timing is everything — treat within 24–48 hours of excision.
- 10–20 Gy in a few fractions with superficial beams.
- Compliance with compression or silicone helps prevent regrowth after radiation.