A Pilot 11C-Choline PET-CT Imaging Study in Patients With Locally Advanced Esophageal Cancer

Abstract

Purpose/Objectives: As concomitant chemoradiation followed by esophagectomy has become standard treatment for locally advanced esophageal cancer, there has been increasing emphasis on identifying a reliable imaging modality to assess treatment response. Given the high false negative and false positive findings with 18F-FDG-PET in the post-treatment setting, many have sought to pursue other radiopharmaceuticals that could potentially better delineate sites of malignancy. Choline, a component of the key cell membrane building block phosphatidylcholine, has emerged as a potential useful radiotracer target for PET/CT imaging in evaluating treatment-response after neoadjuvant chemoradiation. Materials/Methods: Eight eligible patients were selected to undergo baseline and post-treatment 11-C Choline PET/CT imaging. Treatmentrelated changes seen on 11-C Choline PET were then compared to pathologic, radiographic and/or clinical follow-up data. Results: On review of our small series, the observed pCR rate was 25%. Six of the eight patients had 11C Choline PET imaging that correlated with their overall clinical outcomes, as defined by pathology and/or follow-up imaging. Two of eight patients had resolution of their primary lesion following treatment, as visualized on 11-C Choline PET. Neither patient went on to surgery, but both had confirmed negative post-treatment EGD pathology and corresponding negative conventional imaging. Two patients exhibited partial responses to therapy, as seen on 11-C Choline PET, which was confirmed on surgical pathology. A single patient was found to have unchanged disease burden on post-treatment 11-C imaging with subsequent conventional follow up concordant with stable disease. On review of the eight patients, there was a greater difference in preand post-treatment primary lesion SUV observed in patients who reached a CR on 11-C imaging (SUV 7.8) as compared to those who reached PR/SD on 11-C imaging (SUV 2.5). Conclusions: To our knowledge, this is the only prospective pilot study investigating the use of 11-Choline PET/CT for response assessment in locally advanced esophageal cancer treated with neoadjuvant chemoradiation. Although no correlation between SUVmax and pathologic response could be established with such a small cohort, the overall findings support development of a larger trial to investigate the sensitivity, specificity, and positive and negative predictive values of 11C Choline PET/CT for neoadjuvant treatment assessment in esophageal cancer.