PET-CT versus contrast CT for restaging oesophagogastric cancer

Design

Single-centre cohort study with contemporaneous paired imaging

Population

66 patients with oesophagogastric adenocarcinoma restaged after neoadjuvant chemotherapy

Primary outcome

Accuracy for pathological stage, treatment response and metastasis detection

Effect

Comparable for stage; PET-CT better for response (AUC 0.72 vs 0.51); metastasis 8/8 vs 4/8

After neoadjuvant chemotherapy for oesophagogastric adenocarcinoma, both FDG PET-CT and contrast-enhanced CT (CECT) are used for restaging, but whether PET-CT adds enough to justify its cost is unsettled. This single-centre study compared the two in patients who had both scans contemporaneously.

Among 66 patients with matched scans, the two modalities were comparable for predicting pathological tumour stage (area under the curve 0.65 vs 0.62) and nodal stage (0.52 vs 0.53). PET-CT was the better predictor of pathological tumour response (0.72 vs 0.51) and detected all eight cases of metastatic disease at restaging, versus four of eight for CECT, a difference that did not reach significance.

For practice, both are useful for restaging, but PET-CT earns its place where response assessment or occult metastasis would change the plan, typically more advanced disease. Where resources are limited, CECT remains reasonable for stage, with PET-CT reserved for the higher-stakes decisions.

• Single-centre comparison of FDG PET-CT and contrast CT in 66 patients restaged after neoadjuvant chemotherapy.
• The two were comparable for predicting pathological tumour and nodal stage.
• PET-CT better predicted pathological tumour response (AUC 0.72 vs 0.51).
• PET-CT detected all 8 metastatic cases versus 4 of 8 for CECT (not statistically significant).
• Reserve PET-CT for decisions where response or occult metastasis would change management.

Why it matters

It helps target an expensive scan to the patients in whom it changes decisions, rather than ordering it reflexively for all.

Don't overread it

This was a single-centre study of 66 patients, and the metastasis-detection advantage was not statistically significant.

The statistics, in plain English

Comparable AUCs for stage mean neither modality was clearly better there; PET-CT's higher response AUC is meaningful, but the metastasis difference (8 vs 4) did not reach significance in this small sample, so it is suggestive rather than proven.

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