Published online Dec 14, 2019. doi: 10.3748/wjg.v25.i46.6752
Peer-review started: October 15, 2019
First decision: November 4, 2019
Revised: November 12, 2019
Accepted: November 29, 2019
Article in press: November 29, 2019
Published online: December 14, 2019
Processing time: 59 Days and 22 Hours
The 8th edition of the American Joint Committee on Cancer (AJCC) staging system for pancreatic ductal adenocarcinoma (PDAC) excludes extrapancreatic extension from the assessment of T stage and restages tumors with mesenterico-portal vein (MPV) invasion into T1-3 diseases according to tumor size.
In recent studies, MPV invasion is believed to be correlated with a poor prognosis. It would be useful for clinicians and researchers to study on whether the 8th edition of the AJCC staging system of PDAC could accurately predict the prognosis of patients with MPV invasion.
To study whether the inclusion of MPV invasion can further improve the 8th edition of the AJCC staging system for PDAC.
This study retrospectively included 8th edition AJCC T1-3N0-2M0 patients undergoing pancreaticoduodenectomy/total pancreatectomy from two databases: 7539 patients from the surveillance, epidemiology, and end results (SEER) database and 689 patients from the West China Hospital database. Survival data were comprehensively analyzed.
This study showed that MPV invasion is an independent factor for predicting survival. The prognosis of patients with MPV invasion cannot be accurately evaluated according to the 8th edition of AJCC staging. The prognosis of patients with stage IIA and stage IIB was not different. A modified staging system which restages tumors with MPV invasion into T3 diseases outperformed the 8th edition of the AJCC staging system in predicting the prognosis of pancreatic cancer.
This study confirmed that MPV invasion is closely associated with the prognosis of PDAC patients. However, the 8th edition of the AJCC staging could not accurately predict the prognosis of patients with MPV invasion. We demonstrated that tumors with MPV invasion should be incorporated into T3 diseases and developed an available modified staging system that outperformed the 8th edition of the AJCC staging system in predicting the prognosis of PDAC patients.
The T stage of cancer is generally evaluated according to tumor diameter and local extension. Previous staging system evaluated the T stage of pancreatic cancer with extrapancreatic extension which is difficult to be determined, and is differently implemented in each center. With the publication of the 8th edition AJCC cancer staging manual, extrapancreatic extension was excluded from the assessment of T stage of pancreatic exocrine tumors, and the effect of local extension on the prognosis has been neglected (except for artery invasion). The newest data of the SEER database has no information about the extension. However, MPV invasion does have impact on the survival of PDAC patients. We were inspired by the comparison of the prognosis of patients with several different extrapancreatic tissue extensions. Not all the extrapancreatic extension but certain type of local extension should be valued.