When my husband was treated for SCC of the tonsil in 2002, he had concurrent chemorad after a tonsillectomy and then had what the MO called "consolidation therapy" a few months after. The drugs used were Cisplatin and 5FU. He was pretty sick, lost his hair, and dropped weight.
I don't know what the studies indicate, but my husband did experience a recurrence about four years after. I suppose one could speculate that the additional chemo kept the cancer in check for that additional time, or one could also speculate that it did no good whatsoever. Who really knows.
I will share that he was treated with more Cisplatin and additional radiation with the recurrence and is doing well.
Good luck.
Loretta