What dose constraints are appropriate for SBRT treatment to a 5 cm neck metastasis from renal cell carcinoma?

Constraints for thyroid cartilage are not well defined. Trachea/skin one could certainly look up RTOG/NRG, SABR UK consortium, COMET-10 constraints as these are all publically accessible.

To me, the most important questions are as follows:

1. 5 cm is a large met, are there any other mets? Would the e...