Is there data to suggest that definitive chemoradiation to 70Gy vs. postoperative chemoradiation to 60 or 66Gy has any different clinically significant effects on long term swallowing function and other side effects of H&N cancer treatment?

There are no good comparisons. The surgical literature that focuses on TLM/TORS tries to make this claim, but if you look at modern IMRT series, G-tube rates are equivalent, and are in part dependent on T_stage, since a T4 pt is more likely than a T1 pt to get chronic dysphagia. There are also no co...