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.

Duke Scholars

Author Rathan Markandan Subramaniam Radiology