Quantitative Pretreatment CT Parameters as Predictors of Tumor Response of Neuroendocrine Tumor Liver Metastasis to Transcatheter Arterial Bland Embolization

An interpretable machine learning model based on contrast-enhanced CT parameters for predicting treatment response to conventional transarterial chemoembolization in patients with hepatocellular carcinoma

OBJECTIVE

To explore the potential of pre-therapy computed tomography (CT) parameters in predicting the treatment response to initial conventional TACE (cTACE) in intermediate-stage hepatocellular carcinoma (HCC) and develop an interpretable machine learning model.

METHODS

This retrospective study included 367 patients with intermediate-stage HCC who received cTACE as first-line therapy from three centers. We measured the mean attenuation values of target lesions on multi-phase contrast-enhanced CT and further calculated three CT parameters, including arterial (AER), portal venous (PER), and arterial portal venous (APR) enhancement ratios. We used logistic regression analysis to select discriminative features and trained three machine learning models via 5-fold cross-validation. The performance in predicting treatment response was evaluated in terms of discrimination, calibration, and clinical utility. Afterward, a Shapley additive explanation (SHAP) algorithm was leveraged to interpret the outputs of the best-performing model.

RESULTS

The mean diameter, ECOG performance status, and cirrhosis were the important clinical predictors of cTACE treatment response, by multiple logistic regression. Adding the CT parameters to clinical variables showed significant improvement in performance (net reclassification index, 0.318, P < 0.001). The Random Forest model (hereafter, RF-combined model) integrating CT parameters and clinical variables demonstrated the highest performance on external validation dataset (AUC of 0.800). The decision curve analysis illustrated the optimal clinical benefits of RF-combined model. This model could successfully stratify patients into responders and non-responders with distinct survival (P = 0.001).

CONCLUSION

The RF-combined model can serve as a robust and interpretable tool to identify the appropriate crowd for cTACE sessions, sparing patients from receiving ineffective and unnecessary treatments.

Comparison of [18F]-OC PET/CT and contrast-enhanced CT/MRI in the detection and evaluation of neuroendocrine neoplasms

OBJECTIVES

Gallium-68 (68Ga)-labeled somatostatin analog (SSA) PET imaging has been widely used in clinical practice of neuroendocrine neoplasms (NENs). Compared with 68Ga, 18F has a great practical and economic advantage. Although a few studies have shown the characteristics of [18F] AlF-NOTA-octreotide ([18F]-OC) in healthy volunteers and small NEN patient groups, its clinical value needs further investigation. Herein, this retrospective study aimed to evaluate the diagnostic accuracy of [18F]-OC PET/CT in detecting NENs, as well as to compare it with contrast-enhanced CT/MRI.

METHODS

We retrospectively reviewed the data of 93 patients who had undergone [18F]-OC PET/CT and CT or MRI scans. Of these patients, there were 45 patients with suspected NENs for diagnostic evaluation, and 48 patients with pathologically confirmed NENs for detecting metastasis or recurrence. [18F]-OC PET/CT images were evaluated visually and semi-quantitatively by measuring maximum standardized uptake value of tumor (SUVmax), tumor-to-background SUVmax ratio (TBR), and SUVmax of hypophysis (SUVhypophysis). A total of 276 suspected NEN lesions were found in these 93 patients. The results of histopathology or radiographic follow-up served as the reference standard for the final diagnosis.

RESULTS

Forty-five patients with suspected NENs were confirmed by histopathological examination via resection or biopsy. [18F]-OC PET/CT showed high radiotracer uptake in the lesions of G1-G3 NENs. [18F]-OC PET/CT showed superior performance with 96.3% of sensitivity, 77.8% of specificity, and 88.9% of accuracy in diagnosing NENs compared to CT/MRI. When cutoffs of SUVmax, TBR, and SUVhypophysis were 8.3, 3.1, and 15.4, [18F]-OC PET/CT had the best equilibrium between sensitivity and specificity for differentiating NEN from non-NEN lesions. For a total of 276 suspected NEN lesions, the sensitivity, specificity, and accuracy of [18F]-OC PET/CT for diagnosis of NENs were 90.5%, 82.1%, and 88.8%, respectively, and were higher than those of CT and MRI. G1 and G2 NENs had higher TBR and lower CT enhancement intensity than G3. The SUVmax and TBR had a positive correlation with CT enhancement intensity in G2 rather than in G1 or G3.

CONCLUSIONS

[18F]-OC PET/CT is a promising imaging modality for initial diagnosis and detecting metastasis or postoperative recurrence in NENs.

The incidence, prevalence, and survival analysis of pancreatic neuroendocrine tumors in the United States

PURPOSE

The incidence of pancreatic neuroendocrine tumors (pNETs) was increasing. The main purpose of this study was to statistically analyze the incidence and prevalence of pNETs and the main risk factors for the prognosis.

METHODS

Based on the Surveillance, Epidemiology, and End Results (SEER) database, with three registries integrated, this study comprehensively displayed the annual age adjust incidence of pNETs from 1975 to 2018, the estimated 20-year limited-duration prevalence, and conducted the univariate and multivariate survival analysis.

RESULTS

The incidence of pNETs has increased to about 1.5 per 100,000 population, and the prevalence has reached about 0.008% with the aged, Grade 1 and nonfunctional tumors accounting for the majority. The average median overall survival (OS), 5-year survival rate, and median disease-free survival (DFS) of pNETs patients from 1975 to 2018 were 85 months, 57.55%, and 220 months, respectively. From 2000 to 2018, the median OS was 94 months, and the 5-year survival rate was 59.94%. In multivariate survival analysis, the greatest risk factor was Grade 3&4 with HR = 3.62 (3.10-4.28), followed by distant stage with HR = 2.77 (2.28-3.36), and aged over 80 years old with HR = 2.26 (1.33-3.83). Surgery was a protective prognostic factor with HR = 0.34 (0.29-0.40).

CONCLUSION

The incidence and prevalence of pNETs were still increasing, but the trend was gradual and aging in recent years. The survival time of pNETs was longer but has not changed much in recent years. The degrees of malignancy, stage, and operation were the most important prognosis factors.

Prolonged progression-free survival achieved by octreotide LAR plus transarterial embolization in low-to-intermediate grade neuroendocrine tumor liver metastases with high hepatic tumor burden

Objective

To evaluate the efficacy and outcome of transarterial embolization (TAE) plus octreotide long‐acting repeatable (LAR) on patients with low‐to‐intermediate neuroendocrine tumor liver metastases (NETLM).

Methods

One hundred and sixteen patients with G1/G2 NETLM treated with TAE plus octreotide LAR at the First Affiliated Hospital, Sun Yat‐sen University between January 12, 2016 and September 24, 2020 were reviewed. Radiological response was evaluated according to response evaluation criterion in solid tumor version 1.1. Overall progression‐free survival (PFS) was assessed. Intrahepatic and extrahepatic PFS were evaluated in the whole cohort and in patients with the extrahepatic disease (EHD), respectively. Factors affecting treatment response and overall PFS were analyzed using the logistic regression model and Cox proportional hazard model. Adverse events were recorded and evaluated according to Common Terminology Criteria for Adverse Events 5.0.

Results

The median overall PFS of the whole cohort was 13.6 months. For the patients with EHD, the median intrahepatic PFS and extrahepatic PFS were 13.6 and 26.1 months, respectively. The median overall PFS of patients with hepatic tumor burden (HTB) <10%, 10%–25%, 25%–50%, and >50% were 25.2, 13.6, 11.2, and 12.3 months, respectively. Ki67 >10%, HTB >50%, and bone metastasis were independently associated with overall PFS. The objective response rate was 78.4%. In patients with HTB 25%–50% and >50%, responders (complete response or partial response) had significant prolonged PFS compared with nonresponders (stable disease or progression disease). Ki67 >10%, bone metastasis, and clear tumor margin were independently associated with response to TAE. The most frequent adverse events that occurred after TAE were postembolization syndrome, and no treatment‐associated death occurred during the perioperative period.

Conclusion

Transarterial embolization plus octreotide LAR can significantly prolong the PFS of neuroendocrine tumor liver metastases, especially with high HTB over 50%. Selected patients with HTB >25% (ki67 ≤10%, absence of bone metastasis, clear tumor margin) could derive prognostic advantage from the combined treatment.