Dosimetric Results of Postoperative Tomodirect Radiotherapy of Keloid on Ear Cartilage

Abstract

In radiotherapy following surgical excision of a keloid, radiation has been delivered using various techniques, doses, and fractions. TomoDirect (TD) is a static delivery mode of TomoTherapy (Accuray, Sunnyvale, CA, USA), allowing for the use of a fixed gantry angle in place of rotational beam delivery. Described in the present report is the first instance of TD used for postoperative radiotherapy of keloid scar. A 21-year-old woman presented with keloid scar that had developed and gradually progressed on the left ear cartilage following a piercing 2 years prior. The patient underwent TD radiotherapy with 2 tangential beams 33 hours after excision. Dose to planning target volume (PTV) was 15 Gy in 3 fractions of 5.0 Gy daily, every other day, and V95 was 100%. Mean dose of left parotid was 0.21 Gy, and maximum doses of brain and left lens were 0.34 Gy and 0.02 Gy, respectively. Optimal dose and technique for safe and effective postoperative keloid radiation therapy are unclear and depend upon keloid area and size. Treatment of keloid on ear or other sites with TD radiotherapy may be an optimal strategy.