Somatostatin receptor activity assessed by 68Ga-DOTATOC PET can preoperatively predict DAXX/ATRX loss of expression in well-differentiated pancreatic neuroendocrine tumors.

PURPOSE: To evaluate the role of 68Ga-DOTATOC PET parameters in predicting DAXX/ATRX loss of expression in patients with Pancreatic neuroendocrine tumors (PanNET) candidate to surgery. METHODS: This retrospective study included 72 consecutive patients with PanNET (January 2018-March 2022) who underwent to 68Ga-DOTATOC PET for preoperative staging. Image analysis: qualitative assessment and extraction of SUVmax, SUV mean, somatostatin receptor density (SRD), and total lesion somatostatin receptor density (TLSRD) from primary PanNET. Radiological diameter and biopsy information (grade, Ki67) were collected. Loss of expression (LoE) of DAXX/ATRX was assessed by immunohistochemistry on surgical specimen. Student t-test, univariate and multivariate logistic regression and ROC curves have been used to investigate the predictive value of PET parameters on DAXX/ATRX LoE. RESULTS: Forty-two/72 patients had a G1, 28/72 a G2, and 2/72 a G3 PanNET. Seven/72 patients had DAXX LoE, 10/72 ATRX LoE, and 2/72 DAXX/ATRX LoE. SRD and TLSRD could predict DAXX LoE (p = 0.002, p = 0.018, respectively). By evaluating SRD in combination with radiological diameter, only SRD maintained statistical significance (multivariate logistic regression: p = 0.020, OR = 1.05), providing the best prediction (AUC-ROC = 79.01%; cut-off = 46.96; sensitivity = 77.78%; specificity = 88.89%). In the sub-analysis performed on 55 patients with biopsy availability, SRD demonstrated its role in providing useful and additional information (multivariate logistic regression: SRD p = 0.007; grade p = 0.040). CONCLUSION: SRD has a predictive role on DAXX LoE in PanNETs, with higher probability of LoE at increasing SRD values. SRD provides complementary/additional information to grade assessed on biopsy material, and the combined use of these approaches might support patients' management by preoperatively identifying subjects with more aggressive diseases.

Effectiveness and safety of infliximab dose escalation in patients with refractory Takayasu arteritis: A real-life experience from a monocentric cohort.

OBJECTIVES: To evaluate effectiveness and safety of infliximab dose escalation in Takayasu arteritis (TAK) patients. To identify factors associated with refractoriness to standard-dose infliximab. METHODS: Medical records of infliximab-treated TAK patients from a large single-centre observational cohort were reviewed. Infliximab therapy duration, concomitant therapies, and reasons for dose escalation and therapy suspension were evaluated. Occurrence of adverse events was recorded. A comparison between patients who maintained infliximab standard-dose and those who needed dose-escalation was performed. Factors associated with refractoriness to standard dose were analysed. RESULTS: Forty-one patients were included. Starting infliximab dose was 5 mg/kg 6-weekly and 28 patients (68%) needed dose escalation. Persistence/recurrence of clinical symptoms was the most frequent reason for escalation. Median therapy duration was 39 (IQR, 26-61) months in the standard-dose group and 68 (38-87) months in the intensified-dose group. In the intensified-dose-group, infliximab was suspended in eight patients (29%) after a median of 38 (31-71) months, due to loss of response (n = 7) or patient's request (n = 1). Patients in the intensified-dose group had a higher number of relapses (3.4 vs 0.8 events/patient) and received a higher cumulative steroid dose (1.7 [1.6-2.3] vs 1.3 [1-1.6] g/month of prednisone). Three patients from the intensified-dose group had serious infections; one patient from the standard-dose group developed paradoxical psoriasis. At univariate analysis, age at diagnosis and age at infliximab start were associated with infliximab escalation. CONCLUSION: In TAK, dose escalation is safe and allows to optimise infliximab durability in refractory patients. Younger patients seem to be more refractory to standard dosages.

External validation of a convolutional neural network for the automatic segmentation of intraprostatic tumor lesions on 68Ga-PSMA PET images.

Introduction: State of the art artificial intelligence (AI) models have the potential to become a "one-stop shop" to improve diagnosis and prognosis in several oncological settings. The external validation of AI models on independent cohorts is essential to evaluate their generalization ability, hence their potential utility in clinical practice. In this study we tested on a large, separate cohort a recently proposed state-of-the-art convolutional neural network for the automatic segmentation of intraprostatic cancer lesions on PSMA PET images. Methods: Eighty-five biopsy proven prostate cancer patients who underwent 68Ga PSMA PET for staging purposes were enrolled in this study. Images were acquired with either fully hybrid PET/MRI (N = 46) or PET/CT (N = 39); all participants showed at least one intraprostatic pathological finding on PET images that was independently segmented by two Nuclear Medicine physicians. The trained model was available at https://gitlab.com/dejankostyszyn/prostate-gtv-segmentation and data processing has been done in agreement with the reference work. Results: When compared to the manual contouring, the AI model yielded a median dice score = 0.74, therefore showing a moderately good performance. Results were robust to the modality used to acquire images (PET/CT or PET/MRI) and to the ground truth labels (no significant difference between the model's performance when compared to reader 1 or reader 2 manual contouring). Discussion: In conclusion, this AI model could be used to automatically segment intraprostatic cancer lesions for research purposes, as instance to define the volume of interest for radiomics or deep learning analysis. However, more robust performance is needed for the generation of AI-based decision support technologies to be proposed in clinical practice.