What dose would you use for multifocal, recurrent, subtotally resected pleomorphic adenoma of the left neck salivary glands?

A retrospective review of the use of adjuvant radiation in the recurrent setting for pleomorphic adenoma of the parotid gland reported a 20 year actuarial control rate of 94% with a median dose of 50 Gy (45-60 Gy range) (Chen et al. IJROBP 2006). Would you treat to 50 Gy or 60 Gy in this post-operative setting?