Nodal FDG-PET/CT uptake influences outcome and relapse location among esophageal cancer patients submitted to chemotherapy or radiochemotherapy.

PURPOSE: Our aim was investigate whether lymph node uptake is associated with survival and regional relapses, and relapse patterns with respect to the radiotherapy fields in esophageal cancer (EC). MATERIALS AND METHODS: The FDG-PET/CT image datasets of 56 patients were analyzed. All patients underwent definitive or neoadjuvant radio/chemotherapy (RCT). All patients suffering from persistent or recurrent local/regional-only disease after RCT were considered for salvage resection. Patients with adenocarcinoma without metastatic disease were considered for planned resection (usually within 3 months of treatment). RESULTS: Patients with PET-positive lymph nodes before treatment had a worse overall survival and a shorter disease-free survival than those without PET-positive nodes. They also had worse node and metastatic relapse-free survival. N2 patients had statistically significant poorer outcomes than N1-N0 patients and a better survival if the involved nodes were closer to the esophageal tumor. Involved node location by PET/CT also affected global, nodal and metastatic relapses. In addition, an increment of SUVmax value increased relative risk of death and increased relative risk of node and metastatic relapses. The first site of relapse was metastatic recurrence and, second, local recurrence. The most frequent were "in-field" loco/regional recurrence. We observed a relationship between patients classified-N1 and out-field nodal recurrence (p = 0.024), and between patients-N2 and in-field nodal recurrence. The number of PET-positive nodes was an independent significant prognostic predictor for relapse (p < 0.001). CONCLUSION: Our study shows that only FDG-PET/CT can provide prognostic information in EC. Nodal PET/CT uptake influences outcome and relapse location among EC patients.

Radiotherapy volume delineation using 18F-FDG-PET/CT modifies gross node volume in patients with oesophageal cancer.

PURPOSE: Evidence supporting the use of 18F-FDG-PET/CT in the segmentation process of oesophageal cancer for radiotherapy planning is limited. Our aim was to compare the volumes and tumour lengths defined by fused PET/CT vs. CT simulation. MATERIALS AND METHODS: Twenty-nine patients were analyzed. All patients underwent a single PET/CT simulation scan. Two separate GTVs were defined: one based on CT data alone and another based on fused PET/CT data. Volume sizes for both data sets were compared and the spatial overlap was assessed by the Dice similarity coefficient (DSC). RESULTS: The gross tumour volume (GTVtumour) and maximum tumour diameter were greater by PET/CT, and length of primary tumour was greater by CT, but differences were not statistically significant. However, the gross node volume (GTVnode) was significantly greater by PET/CT. The DSC analysis showed excellent agreement for GTVtumour, 0.72, but was very low for GTVnode, 0.25. CONCLUSIONS: Our study shows that the volume definition by PET/CT and CT data differs. CT simulation, without taking into account PET/CT information, might leave cancer-involved nodes out of the radiotherapy-delineated volumes.