Response Evaluation Criteria in Solid Tumors (RECIST) and PET Response Criteria in Solid Tumors (PERCIST) for response evaluation of the neck after chemoradiotherapy in head and neck squamous cell carcinoma

Background An optimal approach to imaging assessment of neck after chemoradiotherapy must be established to avoid unnecessary neck dissection. Methods We retrospectively examined 101 patients and compared between Response evaluation criteria in solid tumors (RECIST), PET response criteria in solid tumors (PERCIST), and positron emission tomography/computed tomography (PET/CT) qualitative assessment. Results PERCIST was superior to RECIST in positive predictive value (PPV; 47% vs. 36%), with equivalent negative predictive value (NPV; 78%). Only 3 of 15 patients with incomplete responses on either RECIST or PERCIST alone had regional treatment failure, and the combination of RECIST and PERCIST improved PPV (55%) without reducing NPV. This combination yielded the highest hazard ratio of regional treatment failure. The combination of RECIST and PET/CT qualitative assessment also improved PPV (50%). In human papillomavirus (HPV)-related oropharyngeal cancer, NPV was 100% across the imaging assessments, while PPV was poor (14%-33%). Conclusions Combining RECIST and PERCIST might optimize decision making in neck management after chemoradiotherapy. HPV status would affect the accuracy of response evaluation.