Estimation of esophageal involvement length in esophagogastric junction tumors using PET-CT

Esophageal involvement length (EIL) is crucial to determining the surgical strategy for esophagogastric junction (EGJ) tumors. This study developed a positron emission tomography-computed tomography (PET-CT)-based method using anatomical landmarks to estimate EIL and evaluated the clinical utility of the model.

We enrolled 50 patients with EGJ adenocarcinoma who underwent surgical resection. Among patients who underwent upfront surgery (Cohort 1, n = 24), craniocaudal distances were measured from the right and left diaphragms and vena cava foramen (VCF) to the proximal tumor margin on PET-CT images and correlated with histological EIL to establish the best-performing model. Predictive ability was validated in patients who underwent surgery after neoadjuvant chemotherapy (Cohort 2, n = 26).

In Cohort 1, among the three anatomical landmarks, VCF most strongly correlated with histological EIL (r = 0.81), providing the following formula: Predicted EIL (mm) = 22 + 0.3 × [Craniocaudal distance from VCF to proximal tumor margin (mm)]. The median absolute difference between the histological and predicted EILs was 4.6 mm (interquartile range, 1.6-6.3 mm), with 96% of cases (23/24) within 10 mm. Evaluation of the model in Cohort 2 found r = 0.81, a median absolute difference of 3.3 mm (interquartile range, 1.1-7.2 mm), and 92% of cases (24/26) within 10 mm. Predictive errors were significantly smaller in both cohorts than in endoscopic findings (Cohort 1, P = 0.004; Cohort 2, P = 0.002).

A PET-CT-based approach using the craniocaudal distance from the VCF to the proximal margin could estimate EIL with sufficient accuracy to support surgical decision-making in clinical practice.