The value of post-neoadjuvant therapy PET-CT in the detection of interval metastases in esophageal carcinoma.

Background: PET-CT scanning is increasingly applied in the primary work-up of esophageal cancer patients. The additional value of a second PET-CT after completion of neoadjuvant therapy (NT) prior to surgery is presently unclear. Therefore, a consecutive series of esophageal cancer patients underwent PET-CT scanning after completion of NT for evaluation of metastatic disease that became manifest under NT.

Methods: A consecutive series of patients planned for curative esophagectomy who underwent a PET-CT prior to and after NT were included in this study. Neoadjuvant therapy consisted of 5FU and cisplatinum combined with 50.4Gy radiotherapy. The first PET-CT was performed as part of the diagnostic work-up, the second PET-CT was performed after completion of NT and prior to surgery. Median interval between NT and second PETCT was 6 weeks. In case of metastatic disease on the post-neoadjuvant therapy PET-CT confirmed by a biopsy, patients were excluded from surgical resection.

Results: Between November 2008 and July 2010 a total of 50 patients underwent first and second PET-CT scanning. 80% of patients was diagnosed with adenocarcinoma, 18% with squamous cell carcinoma. Confirmed metastatic disease on the second PET-CT was present in 4/50 patients (8%). These patients were excluded from resection. A false-positive diagnosis concerning a pulmonary lesion was present in 1 patient (2%); this infiltrate had disappeared on follow up imaging.

Discussion: This study showed development of metastatic disease during NT detected by PET-CT in 8% of esophageal cancer patients, suggesting an additional value of a second PET-CT in order to prevent unnecessary surgical resections.