In patients with nasopharyngeal SCC that have an excellent response to induction chemo, do you alter your chemo-RT dose/volumes in any way?

I agree with Dr. @Dr. First Last. I do not change my volumes based on response to induction chemotherapy. It may be difficult to outline the nodal volume if there is complete response to chemo but I have not really encountered that scenario so far. I use the initial PET and diagnostic CT scans fused...

No

No volume reduction - i.e. include all of pre induction chemo volume. But may reduce dose to appx 60 Gy (like intermediate risk) to that pre chemo volume, while treating any gross residual dz to 70 Gy. We usually don't go above 66 Gy to the plexus and 66 Gy is indeed a tumoricidal dose.

Also as an a...

There is evidence that using post-induction volumes is acceptable Yang et al., PMID 28864073.

There are more recent papers that discuss this:

2024- Lin et al., PMID 40419028

2025- Tang et al., PMID 40907527