Utility of PET/CT in the prediction of response and disease-free survival in locally advanced esophageal cancer

Objectives To evaluate the utility of FDG-PET/CT in the assessment of neoadjuvant therapy response and prediction of disease-free survival in patients with locally advanced esophageal cancer.

Methods Thirty-six patients with locally advanced esophageal cancer (23 squamous cell, 13 adenocarcinoma) treated with neoadjuvant chemoradiotherapy and surgery were included in the study. All patients underwent FDG-PET/CT scans 4 weeks before and after neoadjuvant therapy and were classified in 3 groups based on the decrease of SUVmax between the two PET/CT scans performed. Group 1: Non-significant response (decrease <50%). Group 2: Partial response (decrease >50%). Group 3: Complete response. It was evaluated whether decrease of SUVmax could predict histopathologic response to treatment and Free Recurrence Interval (FRI). Reference standards for treatment response and recurrence were histopathology results.

Results Four patients were excluded due to absence of FDG uptake in the staging PET-CT and two due to dead related to post-surgery complications. Attending to metabolic response, groups 1, 2 and 3 included 4, 22 and 5 patients respectively. Recurrence was detected in 50% of patients of group 1 (avFRI: 13 months), 50% of group 2 (avFRI: 16 m) and 25% of group 3 (avFRI: 25 m). Independent analysis of adenocarcinoma and squamous cell, showed the same recurrence rate (50% en both groups) and very similar avFRI (15 and 17 months respectively).

Conclusions Decrease of SUVmax after neoadjuvant therapy evaluated by PET/CT in locally advanced esophageal cancer seems to be a predicting factor of treatment response and disease-free survival. In our study, patients with adenocarcinoma showed worse metabolic response to neoadjuvant therapy than squamous cell patients, but similar avFRI and recurrence rate