Abstract 2145
Background
The pathological classification of pancreatic neuroendocrine neoplasms (PanNENs) has been revised based on the World Health Organization (WHO) 2017 classification. Well-differentiated PanNENs were previously classified as G1, G2, or G3 according to the Ki-67 labeling index (LI), which shows the cell proliferation ability. Although the Ki67 LI cut-off for G1 and G2 was changed from ≤2% to < 3% from WHO 2010 to 2017, there are few reports on the impact of G2 tumor malignancy associated with this change.
Methods
Patients with PanNENs G1/G2 classified by WHO 2017 Ki-67 LI cut-off who underwent pancreatic resection at our institution between July 1987 and March 2019 were retrospectively analyzed. We excluded patients with synchronous distant metastasis at the time of diagnosis. Their clinicopathological variables were analyzed.
Results
Sixty-two patients (median age: 58 years; range: 18–84 years) were examined. The G1/G2 groups comprised 40/22 and 48/14 patients based on WHO 2010 and 2017 classifications, respectively. Eight patients were reclassified from G2 to G1, two of which were T2 or more based on TNM classification; one patient had lymph node metastasis positivity, and all patients survived without recurrence. Disease recurrence occurred in 4/4 G1/G2 patients according to both WHO 2010 and 2017. G2 patients had shorter 5- and 10-year disease-free survivals (DFSs) than those of G1 patients based on WHO 2010 (90.9% and 90.9% vs. 84.5% and 70.4%, p = 0.179) and significantly shorter DFS based on WHO 2017 (91.9% and 91.9% vs. 78.6% and 58.9%, p = 0.036). The Ki-67 LI cut-off by ROC analysis was 3%, supporting the WHO 2017 classification. In multivariate analysis for DFS, tumor size >25 mm and vascular invasion positivity, but not G2, were risk factors for recurrence. The high-risk group with these factors had significantly worse 5- and 10-year disease-specific survivals (DSSs) compared to the low-risk group (100% and 100% vs. 90.9% and 68.2%, p = 0.045).
Conclusions
Revision of the Ki-67 LI cut-off for PanNENs G1/G2 based on WHO 2017 may be appropriate but G2 is not a risk factor for DFS. Tumor size >25 mm and vascular invasion positivity are potential risk factors. High-risk patients should be closely monitored during follow-up.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
4304 - A user-friendly nomogram to predict relapse-free survival (RFS) in western patients with resected gastric cancer (GC)
Presenter: Massimiliano Salati
Session: Poster Display session 2
Resources:
Abstract
4546 - Efficacy and toxicity of weekly carboplatin and paclitaxel as induction or palliative treatment in advanced esophageal cancer patients
Presenter: Femke de Man
Session: Poster Display session 2
Resources:
Abstract
5908 - Perioperative chemotherapy with Docetaxel, Oxaliplatin, Fluorouracil and Leucovorin (FLOT) versus Epirubicin, Platinum and Capecitabine or Flourouracil (EOX/ECF) in Resectable Gastric or Gastroesophageal Junction Adenocarcinoma- Safety and response data from India.
Presenter: Tanuj Chawla
Session: Poster Display session 2
Resources:
Abstract
937 - Phase II Study of Preoperative Radiotherapy Combined with S-1 plus Cisplatin in Clinically Resectable Type 4 or Large Type 3 Gastric Cancer: OGSG1205
Presenter: Shunji Endo
Session: Poster Display session 2
Resources:
Abstract
1119 - Observational Study of the Peritoneal Washing Cytology Positive Gastric Cancer without Gross Peritoneal Metastasis Underwent Radical D2 Gastrectomy.
Presenter: Jun Eul Hwang
Session: Poster Display session 2
Resources:
Abstract
3744 - Primary results of multicenter phase II study of neoadjuvant chemotherapy with S-1 and oxaliplatin for locally advanced gastric cancer (Neo G-SOX PII)
Presenter: Akira Miki
Session: Poster Display session 2
Resources:
Abstract
5091 - Multicenter Phase I/II Feasibility Study of Adjuvant Treatment with S-1 in Patients after R0-Resection of Adenocarcinoma of the Stomach and Esophagogastric Junction (GMBH-STO-0114)
Presenter: Kathrin Heinrich
Session: Poster Display session 2
Resources:
Abstract
2891 - A phase I study of Docetaxel/Oxaliplatin/S-1 (DOS) combination neoadjuvant chemotherapy for patients with locally advanced adenocarcinoma of the esophagogastric junction
Presenter: Kei Hosoda
Session: Poster Display session 2
Resources:
Abstract
2994 - Apatinib combined with docetaxel in second-line treatment of advanced gastric cancer: a prospective clinical study (Data updated)
Presenter: Mudan Yang
Session: Poster Display session 2
Resources:
Abstract
3000 - A multicenter phase II study of TAS-114 in combination with S-1 in patients with pre-treated advanced gastric cancer (EPOC1604)
Presenter: Daisuke Takahari
Session: Poster Display session 2
Resources:
Abstract