Keloids and Radiation

Radiation therapy following keloidectomy:20-year experience

Kovalic JJ, Perez CA: A Int J Radiat Oncol Biol Phys 17:77, 1989)

The preferred treatment is excision followed by a procedure tailored to prevent fibroblast proliferation leading to recurrence. Although good results have been reported with local injections of triamcinolone, postoperative radiation therapy is effective and is more comfortable for patients.Radiation therapy is usually started within 24 hours after excision, using 100- to 140-kV x-rays with a 1- to 7-mm aluminum half-value layer (HVL) or low-energy electrons with appropriate bolus. The radiation field is custom-shaped with lead, with a 0.5-cm margin around the suture lines. The ear lobes, when treated, are taped away from the face, and a direct anterior or posterior field is used with a small cone. If the lobe is more than 1-cm thick and the wound extends
around it, a higher-energy beam is needed. The total dose is 10 to 15 Gy in two to five fractions in 1 to 2 weeks.

Borok and colleagues used various dose schedules of kilovoltage postoperative irradiation in 375 sites, reporting recurrence in 2.4% (9 sites) and excellent cosmetic results in 92%. They recommended 12 Gy in three fractions immediately after excision. Doornbos and co-workers, reporting results in 218 keloids, demonstrated a dose response relative to total dose, with local control in 21 (40%) of 53 sites receiving less than 9 Gy, compared with 92 (77%) of 120 sites receiving 9 Gy or more. There was a trend for improved local control with doses of 15 Gy. Lo used single-fraction postoperative electron irradiation (1.5 to 3.5 MeV) to treat 168 keloids and hypertrophic scars, reporting local control in 128 (87%) of 147 receiving doses of 9 Gy or greater, compared with 9 (43%) of 21 receiving less than 9 Gy. Klumpar and colleagues found no difference in local control between orthovoltage and electron-beam irradiation. Interstitial irradiation has been used after excision with recurrence rates comparable to those obtained with external-beam irradiation, but it may be associated with more complications and decreased cosmesis. Most recurrences occur within 1 year, and a minimum follow-up of 2 years is recommended.Kovalic and Perez monitored 75 patients with 113 treated sites for a mean of 9.75 years. Most patients were treated to a dose of 12 Gy in three fractions over 3 days delivered with superficial x-rays. The overall local control rate was 73%. No advantage to starting radiation therapy within 1 day of surgery was demonstrated. Significant prognostic factors were size greater than 2 cm, previous treatment, and keloids occurring in men (Table above).

Treatment of established keloids by irradiation alone is not as successful but may be attempted if surgery is not indicated (e.g., in an elderly patient with a large symptomatic lesion or in presternal and shoulder keloids that commonly recur even after combined treatment). Inalsingh reported good results with 4 Gy given once a month for one to five treatments, using energies between 60 and 90 kV. Doornbos and co-workers achieved 90% local control without excision when 15 Gy or more in fractionated doses was given within 1 year after the keloids first appeared. (They treated 15 keloids with 9 to 18Gy in 3- 5 fractions and reported complete disappearance in 11. Keloids present for less than a years responder better (8 of 9) than those present longer (3 of 6.)