Characteristics and risk differences of different tumor sizes on distant metastases of pancreatic neuroendocrine tumors: A retrospective study in the SEER database.

BACKGROUND: The rate of distant metastasis in patients with pancreatic neuroendocrine tumors (PNETs) is 20%-50% at the time of initial diagnosis. However, whether tumor size can predict distant metastasis for PNETs remains unknown up to date. METHODS: We used Surveillance, Epidemiology, and End Results (SEER) population-based data to collect 6089 patients with PNETs from 2010 to 2019. The optimal cut-off point of tumor size to predict distant metastasis was calculated by Youden's index. Multivariate logistic regression analysis was used to figure out the association between tumor size and distant metastasis patterns. RESULTS: The most common metastatic site was liver (27.2%), followed by bone (3.0%), lung (2.3%) and brain (0.4%). Based on an optimal cut-off value of tumor size (25.5 mm) for predicting distant metastasis determined by Youden's index, patients were categorized into groups of tumor size < 25.5 mm and ≥ 25.5 mm. Multivariate logistic regression analyses showed that, compared with < 25.5 mm, tumor size ≥ 25.5 mm was an independent risk predictor of overall distant metastasis [odds ratio (OR) = 4.491, 95% confidence interval (CI): 3.724-5.416, P < 0.001] and liver metastasis (OR = 4.686, 95% CI: 3.886-5.651, P < 0.001). CONCLUSIONS: Tumor size ≥ 25.5 mm was significantly associated with more overall distant and liver metastases. Timely identification of distant metastasis for tumor size ≥ 25.5 mm may provide survival benefit for timely and precise treatment.

Radiofrequency ablation versus liver resection and liver transplantation for small combined hepatocellular-cholangiocarcinoma stratified by tumor size.

PURPOSE: Although radiofrequency ablation (RFA) has been proven to provide a good survival benefit for small hepatocellular carcinoma (HCC), there is limited information about RFA for combined hepatocellular-cholangiocarcinoma (cHCC-CC). The purpose of this study was to explore the clinicopathological features of cHCC-CC and the curative effect of RFA in small cHCC-CC without distant metastases compared with liver resection (LR) and liver transplantation (LT). METHODS: Patients with cHCC-CC, intrahepatic cholangiocarcinoma, or HCC were identified in the Surveillance, Epidemiology, and End Results database. RESULTS: cHCC-CC had the highest rate of poor pathological grade and the lowest rate of bone metastases compared with intrahepatic cholangiocarcinoma and HCC (all P < 0.05). In patients with cHCC-CC after surgery, multivariate analysis showed that compared with RFA, LR and LT were independent protective factors for survival (all P < 0.05). But in cHCC-CC stratified by tumor size, for tumor size ≤ 3.0 cm, there was no significant difference among RFA, LR, and LT in univariate survival analysis (P = 0.285). For tumor size 3.0-5.0 cm, multivariate analysis showed that RFA for cHCC-CC yielded worse survival outcomes in comparison with that of LR (hazard ratio [HR]: 7.51, 95% confidence interval [CI]: 2.09-26.94, P = 0.002) and LT (HR: 4.48, 95% CI: 1.20-16.64, P = 0.025). CONCLUSIONS: In patients with cHCC-CC without distant metastases, for tumor size ≤ 3.0 cm, there was no significant survival difference among RFA, LR, and LT. However, for tumor size 3.0-5.0 cm, RFA may provide a worse survival benefit than LT and LR.

Radiofrequency ablation is an inferior option to liver resection for solitary hepatocellular carcinoma ≤ 5 cm without cirrhosis: A population-based study with stratification by tumor size.

BACKGROUND: About 10%-20% of all individuals who develop hepatocellular carcinoma (HCC) do not have cirrhosis. Comparisons are rarely reported regarding the effectiveness of radiofrequency ablation (RFA) and liver resection (LR) in survival of HCC without cirrhosis and stratification by tumor size ≤ 5 cm. METHODS: We used the Surveillance, Epidemiology, and End Results (SEER) database and identified 1505 patients with a solitary HCC tumor ≤ 5 cm who underwent RFA or LR during 2004-2015. Patients were classified into non-cirrhosis and cirrhosis groups and each group was categorized into three subgroups, according to tumor size (≤ 30 mm, 31-40 mm, 41-50 mm). RESULTS: In patients without cirrhosis, LR showed better 5-year HCC cancer-specific survival than RFA in all tumor size subgroups (≤ 30 mm: 82.51% vs. 56.42%; 31-40 mm: 71.31% vs. 46.83%; 41-50 mm: 74.7% vs. 37.5%; all P < 0.05). Compared with RFA, LR was an independent protective factor for HCC cancer-specific survival in multivariate Cox analysis [≤ 30 mm: hazard ratio (HR) = 0.533, 95% confidence interval (CI): 0.313-0.908; 31-40 mm: HR = 0.439, 95% CI: 0.201-0.957; 41-50 mm: HR = 0.382; 95% CI: 0.159-0.916; all P < 0.05]. In patients with cirrhosis, for both tumor size ≤ 30 mm and 31-40 mm groups, there were no significant survival differences between RFA and LR in multivariate analysis (all P > 0.05). However, in those with tumor size 41-50 mm, LR showed significantly better 5-year HCC cancer-specific survival than RFA in both univariate (54.72% vs. 23.06%; P < 0.001) and multivariate analyses (HR = 0.297; 95% CI: 0.136-0.648; P = 0.002). CONCLUSIONS: RFA is an inferior treatment option to LR for patients without cirrhosis who have a solitary HCC tumor ≤ 5 cm.