Hi Roger,
Kris had a residual hard node left after he finished treatment too. 3 months post Tx he had a PET scan which showed residual activity in that node so the decision was made to have a level 11 - iv neck dissection. This was tricky according to the surgeon as the mass was wrapped around his Carotid artery. However , the good news was that the pathology showed no residual Ca cells. Some atypical cells only and necrotic tissue. Guess that's why a lot here aren't too keen on PET scans as they show up residual inflammation too - this was the case re Kris's residual node.
Have to say he has had no problems from the neck dissection. I did feel all along that it was just dead necrotic tissue but am happier that it was removed.
Wait and see what your PET shows and be guided by the decision of your tumour Board. Our RO did tell us that in 18 months no one would be getting a neck dissection post Tx as Chemo and rads will have done the job.
Try not too worry, You are not long out of Tx and believe that chemo/rads has done its job.
Take care,
Tammy

Caregiver/advocate to Husband Kris age 59@ diagnosis
DX Dec '10 SCC BOT T4aN2bM0 HPV+ve.Cisplatin x3 35 IMRT.
PET 6/11 clear.
R) level 2-4 neck dissection 8/1/11 to remove residual node - necrotic with NED
Feb '12 Ca back.. 3/8/12 total glossectomy/laryngectomy/bilat neck dissection/partial pharyngectomy etc. clear margins. All nodes negative for disease. PEG in.
March 2017 - 5 years disease free. Woohoo!