Abstract
Active surveillance for patients with esophageal cancer with a clinically complete response (cCR) after neoadjuvant chemoradiotherapy (nCRT) is being studied. Active surveillance requires accurate clinical response evaluations (CREs). 18F-FDG PET/CT might be able to detect local tumor recurrence after nCRT as soon as the esophagus recovers from radiation-induced esophagitis. The aims of this study were to assess the value of serial 18F-FDG PET/CT to detect local recurrence in patients beyond 3 months after nCRT and to determine when radiation-induced esophagitis has resolved. Methods: This retrospective multicenter study selected patients with a cCR after nCRT, who initially declined surgery and subsequently underwent active surveillance. CREs included 18F-FDG PET/CT, endoscopic biopsies and endoscopic ultrasound with fine-needle aspiration at regular intervals. Maximum standardized uptake values normalized for lean body mass (SULmax) were measured at the primary tumor site. The percentage change in SULmax (Δ%SULmax) between the last follow-up scan and the scan 3 months post-nCRT was calculated. Tumor recurrence was defined as biopsy-proven vital tumor at the initial tumor site. Results: Of forty-one eligible patients, 24 patients had recurrent disease at a median of 6.5 months post-nCRT and 17 patients remained cancer-free during a median follow-up of 24 months post-nCRT. Five of 24 patients with tumor recurrence had sudden intense SULmax-increases of >180%. In 19 of 24 patients with tumor recurrence, SULmax gradually increased (median Δ%SULmax +18%), whereas SULmax decreased (median Δ%SULmax -12%) in patients with ongoing cCR (P < 0.001, independent-samples t test). In patients with ongoing cCR, SULmax was lowest at 11 months post-nCRT. Conclusion: Serial 18F-FDG PET/CT might be a useful tool to detect tumor recurrence during active surveillance. In patients with ongoing cCR, lowest-SULmax is reached at 11 months post-nCRT, suggesting that radiation-induced esophagitis has mostly resolved by that time. These findings warrant further evaluation in a larger cohort.
- Oncology: GI
- PET/CT
- Esophageal neoplasms
- local neoplasm recurrence
- neoadjuvant therapy
- positron-emission tomography
- watchful waiting
- Copyright © 2020 by the Society of Nuclear Medicine and Molecular Imaging, Inc.