The role of primary tumor SUVmax in the diagnosis of invasion depth: a step toward clinical T2N0 esophageal cancer

BACKGROUND: The controversy regarding optimal clinical T2N0 esophageal cancer treatment ultimately stems from the clinical staging modalities’ inaccuracy. Because most inaccuracies lie in clinical T2 to pathological T1, it is vital to discriminate whether the muscularis propria is invaded. METHODS: We investigated the association between the primary tumor maximal standard uptake value (SUVmax), and the pathological features and overall survival. We attempted to construct a discriminative model through logistic regression analysis. RESULTS: A total of 140 cN0 esophageal squamous cell carcinoma (ESCC) patients were enrolled. Primary tumor SUVmax differed significantly in paired pathological T categories (P<0.05), but not pT2 vs. pT3 (P=0.648). Age (≤65 vs. >65), biopsy differentiation grades (well or moderately vs. poorly vs. unknown), and primary tumor SUVmax (continuous) were independent risk factors for invasion depth. Subsequently, the age categories, the biopsy differentiation grade categories, and the primary tumor SUVmax categories (≤7.4 vs. >7.4) were included in the logistic regression analysis to construct a discriminative model, showing a good performance in discriminating pT2–3 vs. pT1 in terms of accuracy 87.1%, sensitivity 93.6%, specificity 73.9%, and area under the curve (AUC) 0.887 [95% confidence interval (CI): 0.822 to 0.951]. Of these factors, biopsy differentiation grades and primary tumor SUVmax showed significant differences in overall survival (P<0.05), while the age categories did not. CONCLUSIONS: The novel baseline model comprised of age, biopsy differentiation grades, and primary tumor SUVmax provide much discriminative performance in determining whether the muscularis propria is invaded. Further studies are necessary to validate the findings and guide clinical practice for cT2N0 esophageal cancer.