Validation of the eighth edition of the AJCC staging system for patients with pancreatic adenocarcinoma initially receiving chemoradiotherapy and proposal of modifications

Xiaofei Zhu, Di Chen, Yangsen Cao, et al.

Abstract


Objective: To validate the eighth edition of the AJCC staging system in patients with pancreatic adenocarcinoma receiving onlystereotactic body radiation therapy and chemotherapy, and to propose modifications to improve prognostic accuracy.

Methods: Patients with pathologically confirmed pancreatic adenocarcinoma without metastasis who were undergoing onlychemoradiotherapy were included and staged according to the seventh and eighth editions of the AJCC staging system. Meanwhile,another group of stage T4 patients from the above enrollment with only portal vein involvement with or without tumor thrombi(PV ± PVTT) were retrieved for survival comparisons. Modifications were proposed according to the survival comparisons. A cohortfrom the SEER database was used for external validation of the modified staging system.

Results: A total of 683 patients were included. Patients with N2 or N1 but different T stages had significantly different survivaloutcomes according to the eighth edition. The survival of patients with PV ± PVTT was comparable to that of patients with T4tumors. The concordance index of the seventh and eighth editions, and the modified staging system was 0.744 (95%CI: 0.718–0.769),0.750 (95%CI: 0.725–0.775), and 0.788 (95%CI: 0.762–0.813), respectively. For external validation, the concordance index was 0.744(95%CI: 0.718–0.770), 0.750 (95%CI: 0.724–0.776), and 0.788 (95%CI: 0.762–0.814), respectively.

Conclusions: The modified staging system is suggested to have the most accurate prognostic value. Hence, PV ± PVTT should beadded to the definition of T4 tumors regardless of tumor size. Patients with N2 or N1 in different T stages could be regrouped intodifferent substages. Additionally, stage III should be subclassified into IIIA (T3N2 and T4N0) and IIIB (T4N1-2).

Cite this article as: Zhu X, Chen D, Cao Y, Zhao X, Ju X, Shen Y, et al. Validationof the eighth edition of the AJCC staging system for patients with pancreaticadenocarcinoma initially receiving chemoradiotherapy and proposal ofmodifications. Cancer Biol Med. 2020; 17: 492-500. doi: 10.20892/j.issn.2095-3941.2019.0101


Keywords


Chemotherapy; modifications; pancreatic cancer; stereotactic body radiation therapy; the eighth edition of the AJCC staging system

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