Standardized thresholds of volume-based PET/CT parameters predicting survival of patients with pancreatic head cancer treated with stereotactic body radiation therapy

Histology-Based Radiomics for [18F]FDG PET Identifies Tissue Heterogeneity in Pancreatic Cancer

Radiomics features can reveal hidden patterns in a tumor but usually lack an underlying biologic rationale. In this work, we aimed to investigate whether there is a correlation between radiomics features extracted from [18F]FDG PET images and histologic expression patterns of a glycolytic marker, monocarboxylate transporter-4 (MCT4), in pancreatic cancer. Methods: A cohort of pancreatic ductal adenocarcinoma patients (n = 29) for whom both tumor cross sections and [18F]FDG PET/CT scans were available was used to develop an [18F]FDG PET radiomics signature. By using immunohistochemistry for MCT4, we computed density maps of MCT4 expression and extracted pathomics features. Cluster analysis identified 2 subgroups with distinct MCT4 expression patterns. From corresponding [18F]FDG PET scans, radiomics features that associate with the predefined MCT4 subgroups were identified. Results: Complex heat map visualization showed that the MCT4-high/heterogeneous subgroup was correlating with a higher MCT4 expression level and local variation. This pattern linked to a specific [18F]FDG PET signature, characterized by a higher SUVmean and SUVmax and second-order radiomics features, correlating with local variation. This MCT4-based [18F]FDG PET signature of 7 radiomics features demonstrated prognostic value in an independent cohort of pancreatic cancer patients (n = 71) and identified patients with worse survival. Conclusion: Our cross-modal pipeline allows the development of PET scan signatures based on immunohistochemical analysis of markers of a particular biologic feature, here demonstrated on pancreatic cancer using intratumoral MCT4 expression levels to select [18F]FDG PET radiomics features. This study demonstrated the potential of radiomics scores to noninvasively capture intratumoral marker heterogeneity and identify a subset of pancreatic ductal adenocarcinoma patients with a poor prognosis.

The Impact of Metabolic 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Parameters on the Prognosis of Resectable Pancreatic Adenocarcinoma

Objectives

¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) is a useful staging method in pancreatic cancer. The prognosis of pancreatic adenocarcinoma is affected by the tumor stage and resectable state. Maximum standardized uptake value (SUV_max), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of primary tumors are related to prognostic parameters in pancreatic cancer. This study compared ¹⁸F-FDG PET/CT findings with prognostic factors and overall survival of patients with pancreatic cancer.

Methods

Patients with pancreatic adenocarcinoma, referred to our department between 2015 and 2022 for staging, were retrospectively evaluated. Head-to mid-thigh PET/CT images were obtained 1 h after ¹⁸F-FDG injection. Demographic data, survival, and clinical and pathological findings of 39 patients, who underwent surgery after PET/CT imaging, were collected. All primary tumor MTV, SUV_max, background SUV_max, and TLG data have were measured.

Results

The images of 39 patients (24 women and 15 men) with a mean age of 66.62±9.60 years were evaluated. The mean SUV_max, MTV 40%, and TLG of the primary tumors in the pancreatic tissue were 6.28±2.33, 19.33±9.77, and 66.56±45.99, respectively. The average survival after disease diagnosis was 18.97±11.47 (2-55) months. MTV and TLG were significantly higher in patients who died during our study. SUV_max has a significant effect on mortality.

Conclusion

¹⁸F-FDG PET/CT metabolic parameters of SUV_max, MTV, and TLG could help predicting the prognosis of pancreatic cancer preoperatively and follow-up in patients with resectable tumors. Additionally, in our study group tumor grade and perineural invasion significantly affected overall survival.

Prognostic Evaluation Based on Dual-Time 18F-FDG PET/CT Radiomics Features in Patients with Locally Advanced Pancreatic Cancer Treated by Stereotactic Body Radiation Therapy

Background

18F-FDG PET/CT is widely used in the prognosis evaluation of tumor patients. The radiomics features can provide additional information for clinical prognostic assessment.

Purpose

Purpose is to explore the prognostic value of radiomics features from dual-time 18F-FDG PET/CT images for locally advanced pancreatic cancer (LAPC) patients treated with stereotactic body radiation therapy (SBRT).

Materials and Methods

This retrospective study included 70 LAPC patients who received early and delayed 18F-FDG PET/CT scans before SBRT treatment. A total of 1188 quantitative imaging features were extracted from dual-time PET/CT images. To avoid overfitting, the univariate analysis and elastic net were used to obtain a sparse set of image features that were applied to develop a radiomics score (Rad-score). Then, the Harrell consistency index (C-index) was used to evaluate the prognosis model.

Results

The Rad-score from dual-time images contains six features, including intensity histogram, morphological, and texture features. In the validation cohort, the univariate analysis showed that the Rad-score was the independent prognostic factor (p < 0.001, hazard ratio [HR]: 3.2). And in the multivariate analysis, the Rad-score was the only prognostic factor (p < 0.01, HR: 4.1) that was significantly associated with the overall survival (OS) of patients. In addition, according to cross-validation, the C-index of the prognosis model based on the Rad-score from dual-time images is better than the early and delayed images (0.720 vs. 0.683 vs. 0.583).

Conclusion

The Rad-score based on dual-time 18F-FDG PET/CT images is a promising noninvasive method with better prognostic value.

PET metabolic tumor volume as a new prognostic factor in childhood rhabdomyosarcoma

PURPOSE

Childhood RMS is a rare malignant disease in which evaluation of tumour spread at diagnosis is essential for therapeutic management. F-18 FDG-PET imaging is currently used for initial RMS disease staging.

MATERIALS AND METHODS

This multicentre retrospective study in six French university hospitals was designed to analyse the prognostic accuracy of MTV at diagnosis for patients with RMS between 1 January 2007 and 31 October 2017, for overall (OS) and progression-free survival (PFS). MTV was defined as the sum of the primitive tumour and the largest metastasis, where relevant, with a 40% threshold of the primary tumour SUVmax. Additional aims were to define the prognostic value of SUVmax, SUVpeak, and bone lysis at diagnosis.

RESULTS

Participants were 101 patients with a median age of 7.4 years (IQR [4.0-12.5], 62 boys), with localized disease (35 cases), regional nodal spread (43 cases), or distant metastases (23). 44 patients had alveolar subtypes. In a univariate analysis, a MTV greater than 200 cm3 was associated with OS (HR = 3.47 [1.79;6.74], p<0.001) and PFS (HR = 3.03 [1.51;6.07], p = 0.002). SUVmax, SUVpeak, and bone lysis also influenced OS (respectively p = 0.005, p = 0.004 and p = 0.007) and PFS (p = 0.029, p = 0.019 and p = 0.015). In a multivariate analysis, a MTV greater than 200 cm3 was associated with OS (HR = 2.642 [1.272;5.486], p = 0.009) and PFS (HR = 2.707 [1.322;5.547], p = 0.006) after adjustment for confounding factors, including SUVmax, SUVpeak, and bone lysis.

CONCLUSION

A metabolic tumor volume greater than 200 cm3, SUVmax, SUVpeak, and bone lysis in the pre-treatment assessment were unfavourable for outcome.

Clinical Impact of 18F-FDG PET/CT in the Diagnostic Workup of Pancreatic Ductal Adenocarcinoma: A Systematic Review

In this review, the performance of fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in the diagnostic workup of pancreatic ductal adenocarcinoma (PDAC) is evaluated. A comprehensive literature search up to September 2020 was performed, selecting studies with the presence of: sample size ≥10 patients and index test (i.e., “FDG” or “18F-FDG” AND “pancreatic adenocarcinoma” or “pancreas cancer” AND “PET” or “positron emission tomography”). The methodological quality was evaluated using the revised quality assessment of diagnostic accuracy studies (QUADAS-2) tool and presented according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Basic data (authors, year of publication, country and study design), patients’ characteristics (number of enrolled subjects and age), disease phase, type of treatment and grading were retrieved. Forty-six articles met the adopted research criteria. The articles were divided according to the considered clinical context. Namely, besides conventional anatomical imaging, such as computed tomography (CT) and magnetic resonance imaging (MRI), molecular imaging with FDG PET/CT is an important tool in PDAC, for all disease stages. Further prospective studies will be necessary to confirm the cost-effectiveness of such imaging techniques by testing its real potential improvement in the clinical management of PDAC.

A novel combination of percutaneous stenting with iodine-125 seed implantation and chemotherapy for the treatment of pancreatic head cancer with obstructive jaundice

PURPOSE

Insertion of radioactive strips through the biliary stent has been reported to offer longer survival and patency than an uncovered conventional self-expanding metal stent in patients with unresectable malignant biliary obstruction. The aim of this study was to investigate the safety and effectiveness of intraluminal brachytherapy combined with ¹²⁵I seed implantation and transarterial infusion chemotherapy for the treatment of pancreatic head cancer with obstructive jaundice.

METHOD

From October 2012 to January 2018, 21 consecutive patients diagnosed with biliary obstruction caused by locally advanced, nonmetastatic pancreatic cancer with cytologically or histologically confirmed by biopsy were enrolled and receive treatment with intraluminal brachytherapy using ¹²⁵I seed strand and CT-guided percutaneous radioactive seed implantation therapy. The procedure-related and radiation complications were assessed. The outcomes were measured in terms of stent patency, patient survival, complications related to the procedure.

RESULT

One of the 22 patients (4.5%, 1/22) with pancreatic head cancer failed to perform the above procedure because the guidewire was unable to pass through the obstruction segment. The remaining 21 patients (95.5%, 21/22) with pancreatic head cancer with obstructive jaundice were successfully placed with biliary stents and radioactive strips through drainage tubes. The median number of ¹²⁵I seeds loaded was 15, ranging from 12 to 17. After the chemotherapy with gemcitabine and cisplatin, no adverse reaction of Grade Ⅲ ∼ Ⅳ occurred in all cases. Median stent patency was 12.50 months (95% CI: 10.26, 14.74). By May 2019, all 21 patients had died, with overall survival of 5.2-23.3 months, with a median survival of 13.20 months (95% CI: 10.96, 15.44).

CONCLUSION

Percutaneous ¹²⁵I seed implantation combined with insertion of radioactive strips through the biliary stent has the characteristics of less trauma, fewer complications, simple operation, and so on. These procedures bring remission of obstructive jaundice combined with the increased survival for the treatment of obstructive jaundice caused by unresectable pancreatic head cancer if follow-up chemotherapy is carried out. The long-term efficacy of this treatment combination needs to be confirmed by further multicenter, large sample size prospective randomized controlled studies.