Noel Donlon, Jessie Elliott, Claire Donohoe, Conor Murprhy, Tim Nugent, Brendan Moran, Sinead King, Narayasaman Ravi, John Reynolds
Background: The Siewert classification, used to anatomically classify carcinoma of the esophagogastric junction was first proposed in the 1980’s. It has become commonplace since the publication of Siewerts landmark study at the turn of the century. Here we critically evaluate the Siewert classification system and suggest a new classification based on adverse features and tumour biology.
Methods: A prospective maintained database was analysed to identify patients with AEG I, II, III treated with curative intent. Patients were also categorised based on the adverse pathologic features of poor differentiation (PD), lymphatic invasion (LI), vascular invasion (VI), or perineural invasion (PN). Three groupings were defined: no adverse feature, 1–2 adverse features, and 3–4 adverse features.
Results: A total of 650 consecutive patients were treated with curative intent, 358 (55%) post-neoadjuvant therapy. AEG I was significantly (P<0.001) associated with Barrett’s, lower c/p/yp T and c/p/yp N stages, and less LI, VI and PN, but not PD (P=0.08). The aforementioned adverse pathologic features were also associated (P<0.001) with more advanced T, N stages, and fewer major (TRG1/2) histomorphologic responses to neoadjuvant therapy, at 36%, 35%, and 5% for AEG I, II, and III, respectively. By multivariable analysis (y)pT, (y)pN, and the adverse features classification were significant (P<0.001) for survival, as was neoadjuvant therapy (P=0.034) however, this was not the case in the Siewert classification (P=0.577).
Conclusions: The adverse biology scoring system is functional in determining prognosis and response, significantly better than anatomic sub-classification and this is true irrespective of treatment modality.
