Brian,
Ditto what Michele said about occult primary. We also found the unknown primary status extremely distressing and pushed doctors to make sure they had not missed something. I had never considered the possibilty either that it might be gone. I know you just never know with cancer so I have adopted the theory take it as it comes.
Thank you again Brian for keeping all of the invaluable information on this site so up to date.
Kim

Caregiver to Father:Stage III unknown primary; modified left side neck dissection 2/2006; 8 wk trmts of Erbitux 3/2006 with-37 radition treatments; 11.2010; biopsy of base of tongue results questionable. 9.2013 tumor on left side of tongue; squamous cell cancer. 10.2.2013 Hemiglossectomy(1/2 tongue removed) with reconstruct tongue using left thigh tissue;surgery included IORT.
25 additional IMRT radiation trtmts & 5 wks/chemo. Carbo & Taxol combo.NPO;100% PEG depend;aspiration pneumonia 3/2014