For head and neck cancers do you ever reduce PTV coverage in the post-op setting to meet an OAR constraint?

There is no real clinical constraint regarding parotid glands doses. The threshold of 26 Gy mean dose was based on forward-planning IMRT in the early 1990s, which could spare the contralateral but not the ipsilateral glands. Once inverse planning was available and partial sparing of the ipsilateral ...

This question has been examined by Allen Chen et al. if I recall. (PMID 29904734)

In their study, patients (n=305) were treated either with an ipsilateral parotid sparing IMRT technique vs one that prioritized PTV coverage. 49% of their patients were post-op.

For ipsilateral parotid sparing patients,...

I would only do this if it were a low-risk PTV where the risk of nodal spread is very low because of what we know about disease spread and biology. For example, high level II contralateral nodal PTV for a well lateralized T1N1 oral cavity cancer without bulky ipsilateral nodes.

It's great to spare ...