High-dose planned adaptive helical tomotherapy for cutaneous angiosarcoma of the scalp.

Purpose: The purpose of this study was to investigate the feasibility and effectiveness of high-dose planned adaptive intensity-modulated radiation therapy (IMRT) with helical tomotherapy (HT) for cutaneous angiosarcoma (cAS) of the scalp.

Methods: This retrospective cross-sectional included a total of 12 consecutive patients with cAS of the scalp who underwent high-dose planned adaptive IMRT with HT. Prescribed doses were 72.5-74 Gy in 35-37 fractions for the gross tumor volume plus a 1-2 mm margin (PTV1), 58-60 Gy in 29-30 fractions for the clinical target volume plus a 2-3 mm margin (PTV2), and 46 Gy in 23 fractions for the clinical target volume plus a 5-15 mm margin (PTV3) over periods of 7.5, 6 and 4.5 weeks, respectively.

Results: The estimated 1‑year and 2‑year overall survival rate were 65.6% and 27.3%, respectively, and the local progression-free survival at 2 years was 74.1%. All local recurrences were either in or marginal to the PTV2 or PTV3. No local recurrence was observed in the PTV1. All patients tolerated the treatment without grade 3 or higher adverse events during the radiotherapy period. No late adverse events were observed during the follow-up period.

Conclusion: Planned adaptive high-dose IMRT with HT has the potential to improve local control rate without increasing adverse events.