Okay so he his cancer free is what you're saying? This is good.

Ideally what they do upon discover of this type of cancer - is they perform a hemiglossectomy and dissection at the same time then hit him with the IMRT... which it appears they did though the dissection was done a tad later than the initial surgery. Now as far as I gather this was all to the right side of his neck and tongue.

SO, I am not sure what you mean the left side of his neck not responding to chemo and rads... If there was cancer present there they would have radiated it. It is on the opposite side of the surgery and cancer so it may have been left out of the radiation field. They would have treated only if there was evidence of cancer there.

The assumption is that after the surgery he is for all intents and purposes - cancer free. If he has risk factors for recurrence - the amount of nodal involvement in this case would qualify - then they follow up with rads and chemo.

now assuming there is no cancer there... this is just a precaution type treatment.

If they didn't get clear margins on the dissected tumors/nodes then it's more than merely precautionary.

So- in this instance whatever cancer is left is either eliminated during rads and chemo... (which would make him cancer free) or it's not - which would mean he didn't respond to IMRT and chemo, and still has cancer...

so assuming he is as you said cancer free then he should be monitored every three month

if he is not cancer free - then he needs further treatment ASAP and NOT only chemo as it is not curative.

hope I clarified everything.

hugs.