To validate and compare conventional metabolic tumor burden measurements with comprehensive metabolic tumor distribution patterns using [18F] fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) to predict small-cell lung cancer (SCLC) prognosis. This retrospective study included 520 patients with SCLC (mean age ± standard deviation, 67 ± 5.6 years; 84.8% men) who underwent PET/CT for staging. Of these, 364 scans were used for training (n = 291) and internal (n = 73) tests, while 156 other scans were used for external testing. Clinical data (age, sex, and stage) were reviewed. Volumes of interest were manually drawn using a threshold standard uptake value of 2.5 for total lesion glycolysis (TLG) for all tumor lesions on PET. TLG with distribution (TLGd) and organ-based tumor distribution (metastasis in organs, METAORG) was analyzed from CT-based automatic organ segmentation and overlaid on PET. Four survival prediction models (event and duration) were developed using a Random Forest classifier: (1) clinical factors, (2) tumor TLG, (3) TLGd and METAORG, and (4) combined models. The top 11 features were selected for survival duration prediction included clinical factors (age and stage), TLG, five TLGd radiomics features, and three METAORG features (axial and peripheral skeletal distribution patterns and the liver distribution pattern). In the internal test, C-indices for overall survival were 0.611, 0.592, 0.721, and 0.753 for tumor TLG, clinical, METAORG, and combined model, respectively. External test C-indices were 0.637, 0.326, 0.706, and 0.740, respectively. The combined model, which incorporated tumor distribution information such as TLGd and METAORG, demonstrated the highest predictive power for both test sets. The combined model outperformed the other models in predicting survival. Application of tumor distribution (TLGd and METAORG) to whole-body tumor distribution pattern analysis shows promise for improving prognosis evaluation, with advantages of quantifiable metastasis stratification.

ObjectiveTo investigate the value of Fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography ([18F]-FDG PET/CT) in the diagnostic of patients having gastrointestinal (GI) cancers with second primary malignancies (SPMs).MethodsFifty-seven patients (57/1384, 4.1%) diagnosed with SPMs were retrospectively enrolled. The analysis included the following factors: clinical information (sex, age, smoking and drinking history, BMI), site of the second primary tumor, the interval between the diagnoses of the first GI cancer and the SPMs, and histopathology. According to the incidence of SPMs, the patients were divided into lung cancer and non-lung cancer groups. The two groups were compared smoking and drinking history, interval time, distant metastasis, and [18F]-FDG PET/CT-related parameters (maximum standardized uptake value [SUVmax], metabolic tumor volume [MTV], and total lesion glycolysis [TLG]). Twenty-two patients with synchronous cancers were included to compare the Ki-67 index and [18F]-FDG PET/CT-related parameters (SUVmax, MTV, and TLG) between the first and second primary tumors.ResultsThe most common SPMs of the GI system was lung cancer (47.4%, 27/57). Genetic testing revealed abnormalities in three patients, and the pathological type was adenocarcinoma in all three cases. Among the 57 patients diagnosed with multiple cancers (27 synchronous, 30 metachronous), the lung was the most frequent site for both synchronous and metachronous tumors. Between the lung cancer group and the non-lung cancer group differences in the interval between the first GI, age, distant metastasis rate, SUVmax, MTV, and TLG were not statistically significant (P = 0.09, P = 0.288 and P = 0.57). Chest CT and PET/CT were performed preoperatively in all 27 patients in the lung cancer group, and the diagnostic accuracy of PET/CT for the second primary tumor in the group was 100% and chest CT diagnostic accuracy was 77.8%. We found significant differences in the Ki-67 indices between the synchronous cancers (64.5 ± 24.0 vs. 35.1 ± 22.7, p < 0.000). Furthermore, the Ki-67 index was highly expressed in patients with lymph node and distant metastases, but the SUVmax, MTV, and TLG were not significantly different between the groups with lymph node and distant metastases (P = 0.366, P = 0.565 and P = 0.869).ConclusionThe most common SPMs of the GI system was lung cancer. We found that [18F]-FDG PET/CT in patients with GI cancers can help identify primary and metastatic lesions and detect the presence of SPMs at an early stage. Patients with SPMs may have unique characteristics, can be beneficial in helping high-risk patients with early intervention.

This study aimed to assess the prognostic significance of novel and established intratumoral heterogeneity indices (HIs) derived from 18F-fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) and multiparametric composite risk scores (CRS) combining these indices with PET/CT-derived metrics, clinical parameters, and metastatic variables in breast cancer (BC) patients. We retrospectively evaluated 135 BC patients who underwent [18F]FDG PET/CT for pretreatment staging. Metabolic and volumetric data of primary tumors obtained from [18F]FDG PET/CT images, such as the maximum, mean, peak, and minimum standardized uptake values (SUVmax, SUVmean, SUVpeak, and SUVmin), the SUV corrected for lean body mass (LBM) calculated by James's and Janmahasatian's methods (SULmax, SULmean, SULpeak, and SULmin), metabolic tumor volume (MTV), and total lesion glycolysis (TLG), and two predefined and seven novel HIs were compared between molecular subtypes via the Kruskal-Wallis (KW) test. All relevant HI, PET/CT-derived metrics, and clinical, pathological, and metastatic variables were included in the cross-validated LASSO regression models to estimate the overall survival (OS) endpoints for 1, 2, 3, 4, and 5 years. Significant differences were observed between molecular subtypes for SUVmax, SUVpeak, TLG_40, and HI5 (Janma/James) (p < 0.05), with the highest values in the HER2-enriched and triple-negative (TNBC) subtypes. CRS, which combines clinical factors, metastatic status, PET/CT-derived metrics, and HI, demonstrated robust discrimination of OS (area under the curve [AUC]: 0.79-0.91) and outperformed single-parameter models. Among the heterogeneity indices, HI2 and HI4 showed the strongest independent predictions of OS at multiple time points, although a combination of multiple parameters was required for optimal prognostic accuracy. CRS, which integrates imaging-derived heterogeneity and metabolic and clinical data, offers improved OS prediction and individualized risk stratification in BC patients.

Baseline PET-CT in predicting CRS and survival outcomes of R/R MM patients following CAR T-cell therapy

Assessment of the prognostic value of FDG PET-derived markers and responses in POLARIX

Radiomic features from PET-CT enable diagnostic and prognostic stratification in peripheral T-cell lymphoma

Prognostic role of FDG-PET in outcomes of relapsed/refractory large B-cell lymphoma treated with CD3-CD20 directed bispecific antibodies

Clinical contribution of 18F-FDG PET/CT in patients with pediatric bone tissue and soft tissue sarcoma; a retrospective study.

To develop and validate an AI method for automated quantification of whole-skeleton bone marrow (BM) metabolic activity using Carbon 11 (11C)-methionine (MET) PET/CT and to evaluate its prognostic value compared with Fluorine 18 (18F)-fluorodeoxyglucose (FDG) PET/CT in patients with newly diagnosed MM. This prospective study included 49 patients (median age, 68 years; 29 males) with newly diagnosed MM. All patients underwent both 11C-MET and 18F-FDG PET/CT. An AI algorithm initially segments the skeleton on CT images, then propagates the resulting mask to the standardized uptake value (SUV) PET images for automated PET/CT segmentation and quantitative volumetric assessment of BM metabolism. By applying a series of SUV thresholds, the algorithm calculates 11C-MET metabolic tumor volume (MTV) and total lesion methionine uptake (TLMU). Associations with clinical markers (bone marrow plasma cell [BMPC] percentage, serum β₂-microglobulin, International Staging System [ISS]/Revised ISS [R-ISS] stage) and progression-free survival (PFS) were assessed. AI-quantified 11C-MET MTV and TLMU showed significant correlations with BMPC percentage (MTV: r = 0.32, p = 0.02; TLMU: r = 0.31, p = 0.03), serum β₂-microglobulin (MTV: r = 0.29, p = 0.05; TLMU: r = 0.29, p = 0.05), ISS stage (MTV: r = 0.31, p = 0.03; TLMU: r = 0.32, p = 0.03), and R-ISS stage (MTV: r = 0.40, p = 0.02; TLMU: r = 0.37, p = 0.03). In multivariable Cox analysis, both ¹¹C-MET MTV (HR = 1.0023; [95% CI: 1.0004-1.0042]; p = 0.02) and TLMU (HR = 1.0003; [95% CI: 1.0001-1.0005]; p = 0.01) independently predicted PFS. For PFS prediction, 11C-MET MTV (Area Under the Receiver Operating Characteristic Curve [AUC] = 0.743; [95% CI: 0.563-0.903]; p < 0.01) and TLMU (AUC = 0.749; [95% CI: 0.576-0.904]; p < 0.01) outperformed ¹⁸F-FDG PET/CT total lesion glycolysis (TLG) (AUC = 0.713, p < 0.01) and MTV (AUC = 0.719, p < 0.01) using the proposed thresholds. AI-quantified 11C-MET MTV and TLMU act as objective biomarkers of disease burden, they independently predict MM prognosis more effectively than 18F-FDG parameters and may enhance risk stratification.

Background/AimPositron emission tomography/computed tomography with 18F-fluorodeoxyglucose (18F-FDG PET/CT) is frequently used to differentiate schwannomas from malignant peripheral nerve sheath tumors. Schwannomas exhibit pathological heterogeneity, with highly cellular (Antoni A) and hypocellular (Antoni B) areas, but current PET/CT methods do not adequately reflect this heterogeneity. This study aimed to compare imaging characteristics of schwannomas in the trunk versus the extremities, with emphasis on metabolic heterogeneity.Patients and MethodsThis retrospective study included patients with solitary schwannomas who underwent MRI and 18F-FDG PET/CT before surgical excision (June 2013-September 2023). Exclusion criteria were plexiform, multiple, biopsy-only lesions, and tumors originating from internal organs. Tumors were classified as trunk or extremity lesions. MRI was used to determine size and volume, while PET/CT measured SUVmax, SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG). Heterogeneity was assessed using three indices: MTV-to-volume ratio (MTV/volume), SUV-based heterogeneity index (HISUV), and metabolic region-adjusted SUV-based heterogeneity index (MRA-HISUV).ResultsFifty-six patients were included. Trunk schwannomas were larger than extremity tumors in diameter (4.33 cm vs. 2.77 cm; p<0.05) and volume (27.71 cm3vs. 6.25 cm3; p<0.05). SUVmax (4.09 vs. 3.71) and SUVmean (2.47 vs. 2.22) did not differ significantly. MTV (18.43 cm3vs. 6.19 cm3, p<0.05) and TLG (58.41 vs. 14.40, p<0.05) were higher in trunk tumors. MTV/volume ratio was lower (0.77 vs. 1.12, p<0.05), while HISUV and MRA-HISUV were higher in trunk schwannomas (1.79 vs. 1.65 and 2.36 vs. 1.49, p<0.05).ConclusionTrunk schwannomas were larger and exhibited higher metabolic activity and heterogeneity. Novel parameters such as MTV/volume and MRA-HISUV may enhance the characterization of schwannoma heterogeneity.

Ultra-short immunotherapy may spare cutaneous squamous cell carcinoma (CSCC) patients from mutilating surgery, but early identification of (non-)response is needed to safely guide treatment adaptation. This study evaluated the feasibility of sequential [18F]FDG-PET/CT (FDG-PET) as a response biomarker in resectable CSCC patients. In the MATISSE, a randomized phase-II trial, 50 CSCC patients received two courses of neoadjuvant nivolumab (weeks 0 and 2) with or without low-dose ipilimumab (week 0) before surgery (week 4). FDG-PET scans were obtained pre-treatment and shortly prior to surgery to assess the change (Δ) in maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) at the primary tumour and largest (= index) lymph node metastasis (ILN). ΔMTV50%/4.0 and ΔTLG50%/4.0 were calculated using thresholds of 50% SUVmax and SUV ≥ 4.0. In 42 evaluable patients, 31 (74%) patients showed major or partial responses to immunotherapy. EORTC-criteria underestimated response but accurately identified non-responders (70% sensitivity, 100% specificity). In 28 primary tumours and 22 ILNs, a significant reduction in median SUVmax, MTV50%, MTV4.0, TLG50%, and TLG4.0 was observed in responders versus non-responders (overall, p ≤ 0.004, and p ≤ 0.03, respectively). ΔTLG50% and ΔTLG4.0 correlated strongly with response (primary: 92% and 96% accuracy; ILN: 91% and 89% accuracy). Quantitative FDG-PET-response assessment allows early identification of (non-)responders upon neoadjuvant immunotherapy prior to surgery in locoregionally advanced CSCC patients. Early changes in FDG-PET's TLG can support future trials aiming at safe de-escalation of current standard of care surgery with or without adjuvant radiotherapy. EudraCT 2020-001074-30. Registered 9 March 2020, https://www.clinicaltrialsregister.eu/ctr-search/search?query=2020-001074-30.

BackgroundsPatients with differentiated thyroid cancer (DTC) and bone metastases (BM) exhibit heterogeneous radioactive iodine (RAI) and fluorine-18-fluorodeoxyglucose (18F-FDG) uptake patterns at diagnosis. This study is aimed to evaluate clinical outcomes influenced these distinct uptake patterns.MethodsPatients confirmed DTC with BM were involved in this study between 2006 and 2021. All patients received 131I treatment and performed 18F-FDG positron emission tomography with computed tomography (PET/CT) at diagnosis. Variables including patient’s gender, age, pathology, laboratory examination, uptake pattern of bone lesions, treatment protocols, and metabolic parameters of PET/CT were analyzed for the prognosis.ResultsAmong 67 enrolled DTC patients with BM, three uptake patterns were identified: RAI+/PET- (18 patients, 26.9%), RAI+/PET+ (40 patients, 59.7%), and RAI-/PET+ (9 patients, 13.4%). Univariate analysis revealed that age stratification, serum thyroglobulin (Tg) levels, and BM uptake pattern significantly impacted progression-free survival (PFS) and overall survival (OS). Critically, RAI+/PET + patients with RAI(+) ratio > 50% showed better PFS (range 12–156 months, median 38.5 months, p = 0.000) and OS (range 20–156 months, median 61.5 months, and p = 0.012) than those with RAI(+) ratio :le::50% (PFS: range 6-92months, median 24 months; OS: range 28–112 months, median 51 months). Multivariate analysis identified total total lesion glycolysis of all bone lesions (tTLG) from PET/CT as an independent prognostic factor for both PFS and OS (p = 0.021 and p = 0.035, respectively).ConclusionsThe RAI(+) ratio determines clinical outcomes, and the prognosis of RAI+/PET + patients resembles that of RAI+/PET- patients, suggesting similar biological behavior in DTC patients with BM. Pretreatment tTLG is a significant independent prognostic marker for PFS and OS.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12885-025-15036-5.

To assess the detectability of residual tumor-involved lymph nodes (LNs) using 18F-FDG PET/CT and contrast-enhanced CT (CECT) parameters in patients with esophageal squamous cell carcinoma (ESCC) following neoadjuvant immunochemotherapy (NICT). This retrospective study analyzed 161 ESCC patients who received esophagectomy following NICT. All patients underwent preoperative 18F-FDG PET/CT, and 137 also received CECT. Metastatic and nonmetastatic LNs, confirmed pathologically, were evaluated according to the Japanese Esophageal Society (JES) staging system. Diagnostic accuracy was assessed using receiver operating characteristic (ROC) curve analysis and logistic regression was used to integrate metrics for the prediction of LNs status. For overall lymph node analysis, there was no significant difference in diagnostic performance between the optimal PET parameter, total lesion glycolysis (TLG), and the best CECT parameter, short-axis diameter (SAD) (AUC: 0.830 vs. 0.797, P = 0.08). Nevertheless, a combined model incorporating TLG and SAD of PET/CT demonstrated significantly superior diagnostic performance compared to SAD of CECT (AUC: 0.863 vs. 0.797, P < 0.001). In subregional analyses, TLG performed best in the paraesophageal group and abdominal area, with AUCs of 0.824 and 0.857. The SUVmax ratio of lymph nodes to liver blood pool (LLR) demonstrated the highest diagnostic performance in the recurrent nerve group and subcarinal area, with AUCs of 0.885 and 0.884, respectively. 18F-FDG PET/CT is superior to CECT in assessing LNs status in ESCC patients after NICT. The optimal predictive parameters and thresholds vary across LN regions, underscoring the importance of region-specific diagnostic criteria.

Development and validation of a radiomics model based on pretreatment deoxy-2-[fluorine-18]-fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) imaging for predicting lymph node metastasis (LNM) in esophageal squamous cell carcinoma (ESCC). A retrospective analysis was performed on 145 patients with ESCC, using pretreatment 18F-FDG PET/CT imaging data and clinical information. Patients were randomly divided into training and validation cohorts in a 7:3 ratio. In the training cohort, independent risk factors for LNM in ESCC were identified through univariate and multivariate logistic regression analyses. Radiomic features were extracted from the PET images, and the least absolute shrinkage and selection operator (LASSO) regression was used for dimensionality reduction. Features highly correlated with LNM in ESCC were selected. The weighted radiomics score (Radscore) was then calculated based on these selected features. The diagnostic performance of each factor was evaluated using receiver operating characteristic (ROC) curves, and a prediction model nomogram was established. Decision curve analysis (DCA) was conducted to evaluate the clinical utility of the model. Finally, the model was validated using the validation cohort. Maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and gender were significantly associated with LNM in ESCC (all P < 0.05). SUVmax was found to be an independent risk factor for predicting LNM in ESCC. In the training and validation cohorts, the areas under the curve (AUC) for SUVmax combined with Radscore were 0.809 (95% CI: 0.723-0.894) and 0.801 (95% CI: 0.661-0.941), respectively, both of which were higher than those for SUVmax and Radscore alone. A nomogram, a comprehensive predictive model based on SUVmax and Radscore, may improve the net clinical benefit for patients. The nomogram, a predictive model developed using 18F-FDG PET/CT-based radiomics, offers reliable predictive value for LNM in ESCC and is expected to serve as a reference tool for therapeutic decision making in patients with ESCC.

Current guidelines recommend adding local radical therapy (LRT) to systemic treatment in synchronous oligometastatic non-small-cell lung cancer (sOM-NSCLC), but survival data on immunotherapy-based regimens are limited. Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) are prognostic in NSCLC, with higher values linked to worse outcomes. This study examines their association with survival in sOM-NSCLC patients treated with immunotherapy. We conducted a multicenter retrospective study including all consecutive patients with [18F]FDG-PET and brain imaging-staged sOM-NSCLC, between 2015 and 2022, who received first-line (chemo)-immunotherapy and had baseline PET-scan available for review. Subgroups were analyzed based on median MTV and TLG values (high vs. low: H-MTV vs. L-MTV, H-TLG vs. L-TLG). Study endpoints were progression-free survival (PFS) and overall survival (OS), according to MTV and TLG distribution (high vs. low), in the overall population (primary endpoint) and in relation to LRT and systemic treatment type (secondary endpoints). 105 patients were included, 50% were male and 73% had non-squamous histology, median age was 64.9 years. Median PFS was significantly longer for L-MTV vs. H-MTV (14.73 months (95%CI, 7.06-22.40) vs. 7.63 months (95%CI, 5.73-9.52), p = 0.028), but also LRT was associated with PFS (19.04 months (95%CI, 8.47-29.60) versus 7.46 months (95%CI, 5.25-9.67), p = 0.045), while neither MTV nor TLG had impact on OS. In multivariate analysis, only PD-L1 < 50% and soft tissue metastases remained significantly associated with shorter PFS. Baseline MTV is preliminarily associated with PFS in sOM-NSCLC patients treated with immunotherapy, but results are exploratory and need prospective validation in larger cohorts.

Patients with cutaneous squamous cell carcinoma (CSCC) frequently require mutilating surgery and adjuvant radiotherapy (RT). CSCC has been demonstrated to be highly responsive to neoadjuvant anti-PD-1 immune-checkpoint blockade (ICB). However, efficacy and safety of neoadjuvant anti-PD-1 combined with anti-CTLA-4 are lacking. In the MATISSE trial, the primary objective was met to investigate the pathological response rate on neoadjuvant nivolumab (NIVO) and nivolumab plus ipilimumab (NIVO + IPI) at the time of standard of care (SOC: surgery ± RT), defined as the proportion of remaining viable tumor cells in the surgical specimen. Fifty patients with stage I-IVa resectable CSCC were treated with NIVO (weeks 0 and 2) or NIVO (weeks 0 and 2) plus low-dose IPI (week 0) before SOC in week 4. The median follow-up was 31 months. Forty patients underwent SOC; 9 of 20 (45%) patients who received NIVO and 10 of 20 (50%) patients who received NIVO + IPI reached a major pathological response (MPR) and 2 of 20 (10%) patients with NIVO and 6 of 20 (30%) with NIVO + IPI reached a partial pathological response (PPR), resulting in pathological response rates of 55% and 80%, respectively. MPR or PPR was accompanied by 2-year disease-specific survival (DSS) of 100%. ICB was safe with 12% (NIVO) and 8% (NIVO + IPI), grade 3, immune-related toxicity without surgical delays. Ten patients opted to decline surgery and RT, of whom nine reached durable organ preservation and a clinical complete remission on two ICB infusions alone, accompanied by a 2-year DSS of 100% and favorable health-related quality of life. Early changes in [18F]fluorodeoxyglucose positron emission tomography/computed tomography's total lesion glycolysis can safely select patients for response-guided treatment de-escalation in future trials. The ClinicalTrials.gov identifier is: NCT04620200 .

Primary mediastinal large B-cell lymphoma (PMBCL) is a rare, aggressive lymphoma affecting young adults. Interim PET/CT (iPET/CT) scans are used to assess treatment response, but the positive predictive value of standard Deauville score remains limited. This retrospective multicenter study analyzed 116 PMBCL patients treated with anthracycline-based chemoimmunotherapy, focusing on 90 patients with high quality iPET/CT. Semiquantitative radiomics metrics, including changes in maximum standardized uptake value (dSUVmax), metabolic tumor volume (dMTV), and total lesion glycolysis (dTLG), were assessed alongside event-free survival (EFS). All interim and final PET/CT scans were independently reviewed by two nuclear medicine physicians blinded to outcomes. Among the 90 patients, 62 (68.9%) were iPET-positive (Deauville scores 4–5). Event-free survival (EFS) at 3 years was significantly higher in iPET-negative patients compared to iPET-positive patients (75% vs. 29%; p < 0.01). Radiomics analysis demonstrated that dSUVmax, dMTV, and dTLG provided superior predictive accuracy for EFS. Values below optimized cut-off thresholds demonstrated significantly better outcomes (e.g., 3-y EFS: 77.8% for dSUVmax ≥ 80% vs. 11.1% for dSUVmax < 80%, p < 0.01). Radiomics-based metrics outperformed visual iPET/CT assessment in identifying high-risk patients, underscoring their potential in guiding treatment. Future research should integrate radiomics with clinical factors to enhance PET-guided treatment strategies.

Accurate differentiation between non-cancerous, benign, and malignant lung cancer remains a diagnostic challenge due to overlapping clinical and imaging characteristics. This study proposes a multimodal machine learning (ML) framework integrating positron emission tomography/computed tomography (PET/CT) anatomic-metabolic parameters, sarcopenia markers, and inflammatory biomarkers to enhance classification performance in lung cancer. A retrospective dataset of 222 patients was analyzed, including demographic variables, functional and morphometric sarcopenia indices, hematological inflammation markers, and PET/CT derived parameters such as maximum and mean standardized uptake value (SUVmax, SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG). Five ML algorithms-Logistic Regression, Multi-Layer Perceptron, Support Vector Machine, Extreme Gradient Boosting, and Random Forest-were evaluated using standardized performance metrics. Synthetic Minority Oversampling Technique was applied to balance class distributions. Feature importance analysis was conducted using the optimal model, and classification was repeated using the top 15 features. Among the models, Random Forest demonstrated superior predictive performance with a test accuracy of 96%, precision, recall, and F1-score of 0.96, and an average AUC of 0.99. Feature importance analysis revealed SUVmax, SUVmean, total lesion glycolysis, and skeletal muscle index as leading predictors. A secondary classification using only the top 15 features yielded even higher test accuracy (97%). These findings underscore the potential of integrating metabolic imaging, physical function, and biochemical inflammation markers in a non-invasive ML-based diagnostic pipeline. The proposed framework demonstrates high accuracy and generalizability and may serve as an effective clinical decision support tool in early lung cancer diagnosis and risk stratification.

BACKGROUND. Combined positron emission tomography/computed tomography (PET-CT) with [18F]fluorodeoxyglucose is an essential instrument of monitoring the response to chemotherapy in primary mediastinal (thymic) large B-cell lymphoma (PMBCL). Of outstanding interest is the interpretation of PET-CT findings with respect to the frequent persistence of large residual mediastinal tumor after the end of drug therapy in PMBCL patients. AIM. To assess the prognostic value of PET-CT findings at different treatment stages in patients with newly diagnosed PMBCL. MATERIALS &amp; METHODS. This study is based on the clinical data from 28 PMBCL patients (altogether, 131 patients are followed-up) who were treated with R-DA-EPOCH ± radiotherapy at the NN Blokhin National Medical Cancer Research Center from 2011 to 2024. The median age was 35 years (range 21–48 years), most patients were women (n = 23; 82 %). This group of patients was selected because of the availability of PET-CT data to be closely analyzed prior to treatment, after 3 cycles (interim PET-CT), and by the end of the drug stage. This paper focuses on the data of 20 PMBCL patients including not only Deauville criteria (DC) for response but also the following technically determinable volumetric parameters: total metabolic tumor volume (TMTV), total lesion glycolysis (TLG), as well as standardized uptake values (SUVmax, SUVpeak, ΔSUVmax, ΔSUVpeak, and rSUVmax), maximum diameter (Dmax and ΔDmax), and products of perpendicular lesion diameters (PD, ΔPD). RESULTS. With a 23-month median follow-up, the 2-year progression-free survival (PFS) in the total group was 78.6 % whereas the 2-year overall survival was 100 %. Incomplete metabolic response (DC 4–5) was reported in 19 (68 %) patients by the interim PET-CT and in 15 (54 %) patients by the end-of-treatment PET-CT. At the same time, the prognosis in patients with DC 4 and DC 5 was markedly different, but the 2-year PFS in the groups with complete (DC 1–3) and partial (DC 4) metabolic response appeared to be identical and accounted for 85 %. Moreover, all patients with DC 5 showed disease progression after chemotherapy. In PMBCL, two volumetric parameters (TMTV and TLG) have a particularly high prognostic value: the 2-year PFS in the group with high and low TMTV was 40 % and 93 %, respectively, and with high and low TLG it was 57 % and 92 %, respectively. CONCLUSION. PET-negative status (DC 1–3) confirmed already by the interim analysis is a reliable factor for favorable prognosis in PMBCL. After completing drug therapy, a considerable proportion of patients show incomplete metabolic response (DC 4–5). However, long-term survival rates corresponding to DC 4 are noninferior to those in patients with DC 1–3, whereas in patients with DC 5, they are considerably worse. High TMTV and TLG values prior to chemotherapy are associated with unfavorable course of the disease.

Prognostic Value of Pseudotime from Texture Parameters of [18F]fluorodeoxyglucose PET/CT in Resectable Pancreatic Ductal Adenocarcinoma.