Association between the thoroughness of the histopathological examination and survival in patients with esophageal squamous cell carcinoma who achieve pathological complete response after chemoradiotherapy.

ABSTRACT

The College of American Pathologists guidelines recommend examining at least four representative tumor blocks for determining pathological T stage in patients with primarily resected esophageal cancer. Whether the same pathological requirements are adequate in patients undergoing esophagectomy following neoadjuvant chemoradiotherapy (nCRT) remains unclear. We hypothesized that current examination protocols may underestimate the presence of microscopical residual disease after nCRT, potentially leading to under-staging. We retrospectively reviewed the records of patients with esophageal squamous cancer (ESCC) who were diagnosed as having pathological complete response (pCR) following nCRT. The thoroughness of the pathological examination in pCR patients was examined using (i) the number of blocks examined in suspicious tumor area (≤4 vs. >4), and (ii) the block quotient (calculated as the pretreatment tumor length divided by the number of blocks examined in suspicious tumor area). A total of 91 patients were enrolled. The mean number of blocks used to confirm pCR was 4.8 (range 2-14). The 5-year overall survival (OS) and disease-free survival (DFS) in the entire cohort were 55% and 65%, respectively. Multivariate analyses identified the block quotient as the only independent predictor of OS and DFS. Receiver operating characteristic curve analysis indicated an optimal cutoff value of 1.4 for the block quotient. Among the patients who achieved pCR, the 5-year DFS differed significantly between subjects with a low (≤1.4) or high (>1.4) block quotient (76% vs. 47%, respectively, P = 0.03). The block quotient (calculated by the pretreatment tumor length divided by the number of blocks) - which reflects the meticulousness of the histopathological examination for confirming pCR - is associated with survival in ESCC patients.