We had a similar case last week.
P16-negative (different from the U Penn protocol) SCC diagnosed by enlarged nodes in the neck (Level II), no sign of primary. Panendoscopy and PET were negative.
Neck dissection performed with pN2b disease with 4 nodes, ECE present
Tonsillectomy performed during Neck dissection, revealed a 1mm primary in the ipsilateral tonsil. Wide margins (>1 cm), L0.
Now what?
This is a pT1 pN2b tonsil cancer. Adjuvant radiotherapy is indicated because of the pN2b and chemotherapy on top because of the ECE. Good.
We will be including the tonsilar bed, as it would be s.o.c. Because the nodes were actually quite big, we will be treating the contralateral neck too. I am aware that there are quite good data on ipsilateral data only for node-positive tonsil cancer (especially in T1), but the data apply mostly for pN1 or pN2a. This is pN2b disease. It was a debate during the chart round, I would have been comfortable with ipsilateral RT only but was not in the majority.
But let's just assume that the pathologist had missed that 1mm primary in the tonsil. So it would have been a CUP. What would that patient get?
A few may have opted for observation, although I would be against it, data for observation is not good in pN2b.
Most (I assume) would have treated the ipsilateral neck only.
Some would have treated the neck and possible sites of primary ( you would have had a false-negative resected tonsil, so you may have been betting on a primary in the floor of the mouth or the hypopharynx or somewhere else, p16-negativity and the big nodes in level II make it more difficult to guess).
Few may have treated the bilaterall neck + the pharynx.
Perhaps some would have given chemo on-top (no clear data for role of chemo in ECE if it's a CUP)?
