The diversity between curatively resected pancreatic head and body-tail cancers based on the 8th edition of AJCC staging system: a multicenter cohort study

Background: To our knowledge, there are no studies to systematically compare the detailed clinical significance between curatively resected pancreatic head (ph) and body-tail (pbt) ductal adenocarcinoma based on the new 8th edition of AJCC staging system (8 th AJCC stage) that was just applied in clinical practice in 2018. Methods : 351 patients with curatively resected pancreatic adenocarcinoma (PC) from three center hospitals were entered into this multicenter cohort study. Results: Increasing tumor size ( P <0.001), T stage (T1+T2 vs T3+T4, P =0.003), frequent postoperative liver metastasis (PLM) ( P =0.002) and 8 th AJCC stage (IA to VI, P <0.001; I+II vs III+IV, P =0.002) were closely associated with the progression of pbt cancers compared with that in ph cancer patients. Moreover, tumor size≥3cm ( P =0.012), 8 th AJCC stage (III+IV) ( P =0.025) and PLM ( P =0.010) were identified as independent risk factors in pbt cancers in logistic analysis. Patients with pbt cancers had a significantly worse overall survival compared with ph cancer patients ( P =0.007). Moreover, pbt was an independent unfavorable factor in multivariate analysis ( P =0.009). In addition to 8 th AJCC stage, vascular invasion and PLM, increasing tumor size and advanced T stage were also closely associated with the poor prognosis in 131 cases of pbt cancer patients compared with Ph cancer patients. Conclusion: Pbt, as an independent unfavorable factor for the prognosis of PC patients, are much more aggressive than that in ph cancers according to 8 th AJCC staging system. 8 th AJCC staging system are more comprehensive and sensitive to reflect the malignant biology of pbt cancers.