Highly Conformal Ct Based Flap Brachytherapy For Non-Melanoma Skin Cancers Of The Face

Non-melanoma skin cancers (NMSC) in “area H” or the “mask area” of the face are at high-risk for local recurrence due to surface irregularity and proximity to critical structures. Radiation is the treatment of choice when surgery is contraindicated. We hypothesize that catheter Flap HDR brachytherapy will provide high rates of local control and acceptable cosmetic outcomes. Elderly patients with early stage histologically proven NMSC in the “mask area” of the face (central face, eye lids, eye brows, periorbital, nose, lips, mandible, periauricular skin/sulci, ear) were treated with 192Ir HDR brachytherapy delivered via flap applicators (Varian Medical Systems, Inc., Palo Alto, CA). The appropriate applicator was fitted to the inner surface of a thermoplastic cast. CTV included the visible tumor plus a 0.5 cm radial margin, with no additional PTV margin. A total dose of 40 Gy in 8 fractions (5 Gy twice weekly for four weeks) was prescribed to encompass ≥95% of the PTV via CT-based volume planning. Acute skin toxicity was evaluated weekly during radiation using the modified RTOG morbidity criteria. Local response was monitored at periodic intervals after treatment completion. Late cosmetic results were evaluated in all patients using the EORTC skin late radiation morbidity scoring at 6 and 12 months following treatment completion. Local control rates were assessed using Kaplan Meier analysis. Fifty patients with 53 lesions were included with a mean follow-up of 22.3 months. Forty lesions (75%) were located in the “high risk” of the face, including 17 nasal lesions, 8 eye lid tumors and 4 external auricle lesions. Thirteen lesions (25%) were located in the "intermediate risk” regions. Median tumor size and thickness were 1.2 cm and 0.5 cm. Median PTV volume and D90 were 1.7 cc and 92%. 3 patients (5%) experienced acute grade 2 toxicity. 4 patients (8%) continued to experienced chronic grade 1 skin toxicity at 12 months post-RT. 49 lesions (92%) were found to have a good/excellent cosmetic outcome with complete tumor remission. Local control was 95.2% with a mean and median time to failure of 11.3 and 13 months. CT-based flap applicator brachytherapy is a valid treatment option for patients with NMSC of the face when surgery is not feasible. This modality offers high rates of local control with acceptable cosmetic outcomes and low rates of toxicity.