Postoperative radiation protocol for keloids and hypertrophic scars: statistical analysis of 370 sites followed for over 18 months.

Background: Before 2002, keloids and intractable hypertrophic scars were treated at our facility with postoperative irradiation of 15 Gy (the traditional protocol). Analysis of the therapeutic outcomes of patients treated with this protocol showed that the recurrence rates of keloids and intractable hypertrophic scars in the anterior chest wall, as well as the scapular and suprapubic regions, were statistically higher than at other sites, while the recurrence rates in earlobes were lower. Thus, we customized doses for various sites. This report describes our trial of postoperative radiation therapy.

Methods: Between January 2002 and September 2004, 109 patients with 121 keloid and intractable hypertrophic scar sites were treated with surgical excision following the new protocol: electron-beam irradiation at total doses of 10, 15, or 20 Gy, depending on the site. The recurrence rates and toxicities were historically followed in 218 patients with 249 keloid and intractable hypertrophic scar sites treated with the old protocol of surgical removal followed by irradiation at 15 Gy (without variation by site). The minimal follow-up time was 18 months. Statistical analysis was performed using Fisher exact probability test.

Results: Total recurrence rates were 29.3% before 2002 and 14.0% after 2003. The recurrence rate in the anterior chest wall was statistically reduced. Outcomes of earlobe did not differ between irradiation with 15 Gy or 10 Gy.

Conclusions: Keloids and intractable hypertrophic scars should be treated with dose protocols customized by site. Our results suggest that keloid and intractable hypertrophic scar sites with a high risk of recurrence should be treated with 20 Gy in 4 fractions over 4 days and that earlobe should be treated with 10 Gy in 2 fractions over 2 days.