The role of qualitative and quantitative analysis of F18-FDG positron emission tomography in predicting pathologic response following chemoradiotherapy in patients with esophageal carcinoma.

OBJECTIVE

The aim of this study was to determine if a qualitative and quantitative assessment of pre- and post-chemoradiotherapy (CRT) F18-FDG PET scans of esophageal cancer patients could predict for residual disease in esophagectomy specimens.

METHODS

We retrospectively reviewed the records of esophageal cancer patients who had undergone CRT at a single institution. Analysis was limited to esophagectomy patients with both pre- and post-CRT F18-FDG PET scans. The maximum standardized uptake value (SUV), location, and measured length of esophagus with increased F18-FDG uptake were obtained from the PET scan before and 3-4 weeks following CRT (preoperatively). The pattern of F18-FDG uptake was qualitatively assigned a category of diffuse, focal, or diffuse with focal component.

RESULTS

Fifty-seven patients with localized esophageal carcinoma underwent F18-FDG PET/CT scans as part of their initial staging and post-CRT restaging workup, followed by esophagectomy. The pathologic complete response (pCR) rate was 25%. The presence of a focal component on post-CRT PET predicted residual disease on univariate analysis (86% vs. 64%), and achieved significance when controlling for SUV and presence of diabetes on MVA (OR = 5.59, p = 0.028). There was no significant relationship between pre- or post-CRT SUV, tumor histology, or length of increased F18-FDG uptake and presence of residual disease. SUV and focality did not interact significantly to predict residual disease.

CONCLUSIONS

Qualitative but not quantitative PET imaging can help predict increased likelihood of residual tumor in esophageal cancer patients following CRT; however, it is not sensitive enough to solely rule out the presence of residual disease. Additional investigation with a larger cohort of patients is warranted.