It could mean that your tumor has had a "complete response" (CR)to treatment - which means they killed it dead - period.

"Remission" is used more often for cancers that can be arrested temporarily, such as Hodgkins disease or Leukemia, but may come back requiring another round of treatment. Solid tumors often have a "complete response" to treatment.

A "recurrence" would be a new tumor at the original tumor bed (locoregional).

H&N cancers may metastasize however and start new tumors in regional or distant locations, such as the liver, kidneys, lungs or brain.

I have to admit that we don't see many nasal cavity cancers here. The majority are base of tongue or tonsil.