Correlation between standardized uptake value in pre- and post-neoadjuvant chemoradiotherapy and tumor regression grade in patients with locally advanced esophageal cancer.

Abstract

150 Background: A multimodality approach with neoadjuvant chemotherapy and radiation is the standard of care in the United States in the treatment of patients with locally advanced esophageal cancer. It is well established that neoadjuvant chemoradiotherapy (CRT) in these patients can facilitate downstaging, correlating with pathologic response, and improving overall survival. Our clinical practice involves the use of positron emission tomography (PET) to assist with staging in patients prior to undergoing neoadjuvant CRT and surgery. While there has been evidence showing correlation between tumor regression grade (TRG) and increased overall survival in these patients, the relationship between standardized uptake values on PET scans and TRG has not been discerned. The purpose of this study was to determine whether pre and post-chemoradiotherapy SUV on PET scans correlate with TRG in esophageal cancer patients receiving neoadjuvant chemoradiotherapy. Methods: A retrospective review of 56 patients with stage II-III esophageal cancer treated with neo-adjuvant CRT followed by surgery was performed. Pre- and post- treatment PET scans were reviewed. Maximum SUV at the site of the primary tumor was recorded. Upon completion of surgery, tumor regression grade was determined by a specialized pathologist. Spearman correlation was used to compare pre, post, and change in max SUV, to the 4 level TRG variables. Results: The median follow-up was 24 months. No significant correlation was found between pre-treatment or post treatment SUV and TRG with p value of 0.73 and 0.94 respectively. There was no significant correlation between decreased FDG uptake following CRT and TRG with p value of 0.82. Consistent with previous data, TRG predicted the therapeutic efficacy and prognosis for patients with locally advanced esophageal carcinoma treated by neoadjuvant chemotherapy. Conclusions: Our results are preliminary and retrospective in nature. A larger sample is needed to confirm these findings. Decreased FDG uptake in sequential PET scans strongly correlates with tumor response, but is not accurate enough to predict pathological response.