Prognostic value of the 2017 World Health Organization Classification System for gastric neuroendocrine tumors: A single-center experience.

BACKGROUND/AIMS: Gastric neuroendocrine tumors (G-NETs) are rare tumors, but their incidence is gradually increasing. Despite the existence of many classification systems, determining prognosis and planning treatment in patients with G-NETs remains a clinical challenge. In this study, the prognostic value of the World Health Organization (WHO) 2017 grading system and the effect of surgery on survival in low grade neuroendocrine tumors were investigated. MATERIALS AND METHODS: G-NETs who were diagnosed between January 2000 and May 2017 were included in the study. Patients' demographic characteristics, treatment details, and survival data were obtained from medical charts. Pathological samples were re-classified according to the WHO 2017 grading system. RESULTS: Of the total 94 evaluated patients, 50 (53.2%) were classified with G1 NETs, 37(39.4%) with G2 NETs, 4(4.2%) with well-differentiated G3 NETs, and the remaining 3 patients with poorly differentiated G3 neuroendocrine carcinoma (NEC). The median follow-up time was 83.2 months. There was a statistically significant difference in 5-year progression free survival (PFS) between G1 tumors (100%) and G2 tumors (76%) (p<0.001). However, there was no statistically significant deference in 5-year overall survival rate (OS) for G1 (97%) and G2 (82%) tumors (p=0.141). When G2 and G1 NETs were compared according to their surgical approach, radical surgery was more frequently performed in patients with G2 tumors (p<0.001). However, radical surgery did not improve PFS in G1 and G2 NETs. CONCLUSION: The WHO 2017 NET classification system may have low prognostic value for determining the prognosis of patients with G1 and G2 tumors. Radical surgery for G1 and G2 NETs did not improve PFS in our study.

Oncological predictive value of the 2004 World Health Organisation grading classification in primary T1 non-muscle-invasive bladder cancer. A step forward or back?

OBJECTIVE: To compare the clinical reliability of the 1973 and 2004 World Health Organisation (WHO) classification systems in pT1 bladder cancer. PATIENTS AND METHODS: We retrospectively evaluated 291 consecutive patients who had pT1 high grade bladder cancer between 2004 and 2011. All tumours were simultaneously evaluated by a single uro-pathologist as high grade and G2 or G3. All patients underwent a second transurethral resection (TUR) and those confirmed with non-muscle-invasive bladder cancer at second TUR received bacille Calmette-Guérin. Follow-up included urine cytology and cystoscopy 3 months after second TUR and then every 6 months for 5 years. Univariate and multivariate analysis to determine recurrence-free survival (RFS) and progression-free survival (PFS) rates were performed using the Kaplan­Meier method with the log-rank test. RESULTS: G2 tumours were found in 124 (46.6%) and G3 in 142 (53.4%) patients. The mean (median; range) follow-up period was 31.1 (19; 1­93) months. The 5-year RFS rate was 39.1% for the overall high grade population, and 49.1 and 31.8% for G2 and G3 subgroups, respectively. The 5-year PFS was 82% for the overall high grade population and 89 and 73% for G2 and G3 subgroups, respectively. RFS (P < 0.002) and PFS (P < 0.001) rates were significantly different between the G2 and G3 subgroups. In multivariate analysis, only the grade assessed according to the 1973 WHO significantly correlated with both RFS (P = 0.003) and PFS (P < 0.001). CONCLUSION: The results suggest that the 1973 WHO classification system has higher prognostic reliability for patients with T1 disease. If confirmed, these findings should be carefully taken into account when making treatment decisions for patients with T1 bladder cancer.