{'fraction_non_alphanumeric': 0.054000981836033385, 'fraction_numerical': 0.041237113402061855, 'mean_word_length': 4.405835543766578, 'pattern_counts': {'":': 0, '<': 2, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Timing and Impact of Posttreatment PET/CT After First 6 Months on Patient Management and Outcomes in Oropharyngeal Squamous Cell Carcinoma.

OBJECTIVE
The objective of this study was to investigate the impact of PET/CT on patient management and outcomes of oropharyngeal squamous cell carcinoma (OPSCC) after the first 6 months following treatment.


MATERIALS AND METHODS
We retrospectively identified patients with OPSCC who underwent chemoradiation therapy and had at least 2 years of posttreatment follow-up. Patients were grouped on the basis of whether they underwent PET/CT, as a result of clinical suspicion of recurrence or routine follow-up, in the last 18 months of the 2-year posttreatment period (experimental group) or not (control group). Association between PET/CT use and change in management was tested using chi-square analysis. Survival analyses were performed with Cox and Kaplan-Meier analyses.


RESULTS
In total, 149 patients underwent 294 PET/CT studies in the 2-year follow-up period. Eighty-three patients (55.7%) underwent PET/CT in the last 18 months of the 2 years. This group underwent 223 PET/CT studies, 22 (9.9%) of which were positive. Sixteen of the 22 (72.7%) changed management. Sixty-six patients (44.3%) did not undergo PET/CT in the last 18 months. This group underwent 71 PET/CT studies, six (8.5%) of which were positive. Two of the six studies (33.3%) changed management. Of first-time positive PET/CT studies in the last 18 months, five of nine (55.6%) were performed 6-12 months after treatment. PET/CT in the last 18 months was positively associated with change in management (odds ratio, 4.88; p = 0.02). Patients with positive PET/CT findings had worse overall survival (hazard ratio [HR], 31.6; p < 0.0001) and progression-free survival (HR, 40.8; p < 0.0001).


CONCLUSION
PET/CT in the last 18 months of the 2-year posttreatment period impacted patient management. Most first-time positive PET/CT studies in the last 18 months of the 2 years were performed 6-12 months after treatment.