Give it time.
The Study: The next obvious question is whether a lack of response at the tested time point of 12 weeks mandates a dissection. Here is a lookback at 254 patients with node(+), HPV(+) oropharyngeal cancer with a 12-week PET demonstrating a complete response at the primary site with no evidence of metastatic disease. All patients with a complete PET-response in nodes (defined as uptake less than background, n=194) underwent standard clinical surveillance. The rest, with an incomplete PET-response (n=41), were re-imaged with another PET at 16 weeks. Notably, at 16 weeks, 29 of these 41 (71%) were found to be complete-responders having been treated with nothing but more time. Among the other 12 of 41, 4 had reduced avidity, 8 had stable avidity, and none had clinical progression. In the end, only 6 patients underwent planned neck dissection, and, most importantly, locoregional control at 5 years was an impressive 93% across the board.
Bottom Line: Not only can the majority of patients avoid a neck dissection following definitive chemoradiation for HPV(+) oropharyngeal cancer based on re-staging PET at 12 weeks, the majority of the remaining patients can also avoid one with another PET at 16 weeks. | Hy, Oral Oncol 2019