Aim:Predicting axillary pathologic complete response (pCR) after neoadjuvant systemic therapy (NST) may enable risk-adapted axillary management in clinically node-positive breast cancer (BC), but practical baseline PET-derived predictors are limited. Methods:Single-center retrospective cohort of consecutive cN+, M0 patients with baseline [18F]FDG PET/CT-reported axillary nodal metastasis treated with NST and surgery (complete-case n=115). Axillary pCR was defined as no residual invasive carcinoma in axillary lymph nodes; isolated tumor cells and/or micrometastases were classified as non-pCR. Two prespecified ridge-penalized logistic models combined routine clinical variables with baseline PET-defined axillary burden as (i) hypermetabolic ALN count (Model A) or (ii) limited (1-3) versus advanced (≥4) burden group (Model B). Stratified 5-fold cross-validation generated out-of-fold (OOF) predictions; AUC, Brier score, and logistic recalibration slope/intercept were bootstrapped on OOF predictions (2000 resamples). Results:Axillary pCR occurred in 59/115 (51.3%). Discrimination was good: AUC 0.80 (95% CI 0.72-0.88) for Model A and 0.79 (95% CI 0.71-0.87) for Model B. Calibration was acceptable (bootstrap-mean slope/intercept ≈1.10/0.04 and 1.08/0.03, respectively). Greater baseline PET-defined axillary extent was associated with lower odds of pCR; molecular subtype and neoadjuvant anti-HER2 therapy remained strongly associated with response. Conclusion:Prespecified ridge models combining routine clinical variables with baseline [18F]FDG PET/CT-defined axillary burden showed good internal performance for predicting axillary pCR. External validation is required before response-adapted clinical use.

The aim of this study is to explore the association between baseline [18F]fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT)–derived metabolic parameters and blood-based systemic inflammatory indices in a real-world breast cancer (BC) cohort and to evaluate their associations with overall survival (OS). Our single-centre retrospective cohort study included 247 BC patients who underwent pre-treatment baseline [¹⁸F]FDG PET/CT imaging. PET-derived metabolic parameters, including lean body mass–normalised peak uptake (SULpeak) and background-normalised bone marrow activity (bone marrow–to–liver ratio; BLRmean), were evaluated alongside systemic inflammatory indices derived from complete blood counts (CBC), namely the systemic immune-inflammation index (SII) and the pan-immune-inflammation value (PIV). OS was the sole study endpoint. To reduce clinical heterogeneity, analyses were stratified by disease stage and performed separately in Non-metastatic (Non-met) (stage I–IIIC) and metastatic (MET) (stage IV) cohorts. We fitted prespecified Cox proportional hazards models with all continuous predictors z-standardised, and hazard ratios were expressed per 1-standard deviation increase. Model performance was evaluated at clinically relevant time points of 12, 36, and 60 months. In prespecified Cox proportional hazards models, age and BLRmean were associated with OS. The addition of PET-derived or systemic inflammatory metrics provided limited incremental discrimination. Discriminative performance was higher at earlier follow-up intervals and declined at longer time horizons. Findings in the MET cohort showed similar directional patterns, although with reduced precision. In this real-world BC cohort, stage-stratified analyses indicate that age and background-normalised bone marrow metabolic activity provide modest but consistent prognostic information for OS across prespecified models, particularly in Non-met disease. The incremental prognostic value of systemic inflammatory indices and tumour uptake metrics was limited.

Fibroblast activation protein inhibitor (FAPI) PET is an emerging molecular imaging modality that is widely used in oncology and increasingly investigated in nononcologic diseases. Abdominal wall endometriosis (AWE) is a rare form of endometriosis, characterized by ectopic endometrial tissue in the abdominal wall. We present a patient with a right external obturator mass, biopsy-confirmed as endometriosis, in whom 68 Ga-FAPI-04 PET/CT revealed extensive multifocal AWE and adenomyosis. These lesions demonstrated intense FAPI uptake, in contrast to their low or absent FDG uptake. This case highlights the potential of FAPI PET for detecting atypically located endometriosis, a capability lacking in current imaging methods.

Purpose The aim of this study is to explore the association between baseline [F-18]fluorodeoxyglucose positron emission tomography/computed tomography ([F-18]FDG PET/CT)-derived metabolic parameters and blood-based systemic inflammatory indices in a real-world breast cancer (BC) cohort and to evaluate their associations with overall survival (OS). Methods Our single-centre retrospective cohort study included 247 BC patients who underwent pre-treatment baseline [& sup1;F-8]FDG PET/CT imaging. PET-derived metabolic parameters, including lean body mass-normalised peak uptake (SULpeak) and background-normalised bone marrow activity (bone marrow-to-liver ratio; BLRmean), were evaluated alongside systemic inflammatory indices derived from complete blood counts (CBC), namely the systemic immune-inflammation index (SII) and the pan-immune-inflammation value (PIV). OS was the sole study endpoint. To reduce clinical heterogeneity, analyses were stratified by disease stage and performed separately in Non-metastatic (Non-met) (stage I-IIIC) and metastatic (MET) (stage IV) cohorts. We fitted prespecified Cox proportional hazards models with all continuous predictors z-standardised, and hazard ratios were expressed per 1-standard deviation increase. Model performance was evaluated at clinically relevant time points of 12, 36, and 60 months. Results In prespecified Cox proportional hazards models, age and BLRmean were associated with OS. The addition of PET-derived or systemic inflammatory metrics provided limited incremental discrimination. Discriminative performance was higher at earlier follow-up intervals and declined at longer time horizons. Findings in the MET cohort showed similar directional patterns, although with reduced precision. Conclusions In this real-world BC cohort, stage-stratified analyses indicate that age and background-normalised bone marrow metabolic activity provide modest but consistent prognostic information for OS across prespecified models, particularly in Non-met disease. The incremental prognostic value of systemic inflammatory indices and tumour uptake metrics was limited.

Endometriosis is a chronic condition in reproductive-age women, and diagnosis can be delayed for 4-11 years due to nonspecific symptoms and limited imaging. This underscores the need for new methods to overcome these diagnostic challenges. Fibroblast activation protein, strongly expressed in the perilesional stroma of endometriotic lesions, is a promising PET target. We included 8 women who underwent 68Ga-FAPI-04 PET/CT for cyclic pelvic or extrapelvic pain and solid nodular lesions, later histopathologically confirmed as endometriosis. In these patients, we showed the targeting diagnostic potential of FAPI PET/CT and endometriotic foci with high accuracy compared with other imaging methods.

Adipose tissue may contribute to systemic inflammation in breast cancer. This study evaluated whether visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) [18F]fluorodeoxyglucose ([18F]FDG) uptakes on positron emission tomography/computed tomography (PET/CT) are associated with inflammatory indices after adjustment for PET-derived tumor metabolic burden and whether metastatic status modifies these associations. In this retrospective single-center cohort (n = 358) undergoing baseline [18F]FDG PET/CT, metastatic status was defined using an internal three-level clinical stage grouping: early-stage or locally advanced disease was classified as M0 and metastatic disease was classified as MET. VAT and SAT FDG uptakes were quantified as z-scored mean standardized uptake values normalized to lean body mass (SULmean) using the James lean body mass equation. Inflammatory indices from complete blood counts were log-transformed. Prespecified linear regression models with heteroskedasticity-consistent type 3 (HC3) robust standard errors were adjusted for age, body mass index (BMI), fasting glucose, stage, molecular subtype, and PET-derived primary-tumor metabolic burden metrics. Effect modification was tested via exposure × MET interaction. Sensitivity analyses used total-body tumor burden metrics in MET and recalculated SUL using the Janmahasatian lean body mass equation; overall survival (OS) was explored with Cox models. Of 358 patients, 284 (79.3

Fibroblast activation protein inhibitor (FAPI) PET is an emerging molecular imaging modality that is widely used in oncology and increasingly investigated in nononcologic diseases. Abdominal wall endometriosis (AWE) is a rare form of endometriosis, characterized by ectopic endometrial tissue in the abdominal wall. We present a patient with a right external obturator mass, biopsy-confirmed as endometriosis, in whom 68Ga-FAPI-04 PET/CT revealed extensive multifocal AWE and adenomyosis. These lesions demonstrated intense FAPI uptake, in contrast to their low or absent FDG uptake. This case highlights the potential of FAPI PET for detecting atypically located endometriosis, a capability lacking in current imaging methods.

To investigate whether whole-brain (WB) metabolic activity measured on pretreatment [18 F]FDG PET/CT provides prognostic information beyond global metabolic tumour burden in patients with breast cancer. This single-centre retrospective cohort included 358 patients with biopsy-confirmed breast cancer who underwent pretreatment [18 F]FDG PET/CT for staging. WB SUVmean, WB SULmean, and total metabolic tumour volume (TMTV) were measured using a semi-automated PET/CT analysis workflow. The primary endpoint was overall survival (OS). Sequential Cox models evaluated the incremental prognostic value of WB SUVmean beyond clinical variables and TMTV; WB SULmean was assessed in sensitivity analysis. Complete-case data were available for 354 patients. In univariable analysis, higher TMTV was associated with worse OS (HR 1.167 per 100 mL; P < 0.001), whereas higher WB SUVmean (HR 0.785; P < 0.001) and WB SULmean (HR 0.733; P < 0.001) were associated with better OS. After adjustment for age, body mass index, disease extent, fasting glucose, and TMTV, WB SUVmean remained independently associated with OS (HR 0.810, 95

Objective: This study aimed to evaluate whether adding a broad set of pre-treatment [18F] fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) metabolic and volumetric parameters to routine clinical variables improves the prediction of overall survival (OS) in patients with gastric cancer (GC). Secondary objectives were to assess the prognostic value of blood-and spleen-normalized metabolic indices and to explore associations between PET metrics and HER2 status. Methods: In this retrospective cohort, pre-treatment 18F-FDG PET/ CT data were analyzed to extract standardized uptake value (SUV)and volume-based PET metrics, BLR_mean, and SLR_mean. Clinical variables, pathological features, treatment details, HER2 status, and survival outcomes were obtained from institutional records. OS was calculated based on the date of initial management. Prognostic performance was evaluated using Cox models, calibration metrics, time-dependent area under the curve (AUC), and decision curve analysis (DCA). Nested models (clinical-only vs. clinical+PET) were compared to determine the incremental value. Results: SUV-and volume-based PET metrics showed variable but directionally consistent associations with OS. Metabolic tumor volume (MTV_40) and total lesion glycolysis (TLG_40) demonstrated trendstoward worse outcomes, although these effects did not consistently reach statistical significance in multivariable analyses. Blood-and spleen-normalized parameters (BLR_mean and SLR_mean) showed stronger effects in the PET-only model but became attenuated after adjustment for clinical covariates. Incorporating PET parameters into the clinical model modestly improved discrimination and yielded acceptable calibration. HER2-positive tumors exhibited higher metabolic activity; however, no significant interaction was observed between HER2 status and the prognostic effect of PET metrics. Across clinically relevant decision thresholds (10-40%), the combined Clinical+PET model achieved higher net benefitthan the clinical model alone. The combined model demonstrated a higher net benefit at 12 and 24 months. Conclusion: Pretreatment 18F-FDG PET/CT appears to provide additional prognostic information beyond routine clinical variables in GC. The inclusion of SUV-based, volumetric, and normalized metabolic parameters modestly improves risk stratification and is associated with favorable decision-analytic performance. These findings support integrating quantitative PET metrics into prognostic evaluation frameworks for patients undergoing management for GC.

A 60-year-old man with signet-ring-component poorly differentiated rectal adenocarcinoma (pMMR, HER2-negative, KRAS/NRAS/BRAF wild-type) received total neoadjuvant therapy, low anterior resection, and adjuvant CAPOX. During biochemical progression (CEA 7.85 → 171.0 µg/L over ∼4 mo), 18F-DG PET/CT showed postoperative/anastomotic uptake (SUVmax 8.5) without definite peritoneal-serosal disease. 68Ga-FAPI-04 PET/CT performed 38 days later demonstrated intense uptake in peritoneal-serosal and mesenteric implants (SUVmax 51.2), the anastomotic and colostomy-site regions (SUVmax 9.3), and a Couinaud segment VI hepatic lesion (SUVmax 6.3). The case illustrates the complementary value of 68Ga-FAPI-04 PET/CT in suspected stromal-rich peritoneal recurrence in a sequential imaging setting.

A 49-year-old father and his 18-year-old son were diagnosed with multiple endocrine neoplasia syndrome type 1 (MEN-1). 68 Ga-DOTATATE PET/CT detected several insulinomas, and subsequent surgical intervention resulted in a complete cure. The father and son patients have both experienced episodes of hypoglycemia, in addition to having a parathyroid adenoma and a pituitary adenoma. Patients exhibit elevated levels of insulin, C-peptide, calcium, corrected calcium, parathyroid hormone (PTH), and prolactin.

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 [18 F]FDG PET/CT for pretreatment staging. Metabolic and volumetric data of primary tumors obtained from [18 F]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.

Subcutaneous emphysema may occur iatrogenically, spontaneously, or post-traumatically as a result of free air passage under the skin from the respiratory tract or gastrointestinal tract. In this case, we present the typical appearance of a case of massive subcutaneous emphysema observed on [18F]-FDG PET/CT for metabolic characterization due to a massive lesion in the lung and the images of complete resorption after seven months.

The PRIMARY scoring system is a scale designed to identify clinically significant intraprostatic malignancies on 68Ga-PSMA PET/CT images. Active surveillance is a management method for patients with low-risk prostate cancer. In this study, we aimed to assess the efficacy of PRIMARY scoring in identifying appropriate candidates for active surveillance based on the distribution within prostate cancer risk groups. The data of 134 patients diagnosed with PCa by biopsy who underwent 68Ga-PSMA PET/CT imaging for post-diagnostic staging purposes were retrospectively analyzed. Age, total PSA, ISUP grade, prostate lesion SUVmax values, PI-RADS scores, and PRIMARY scores were recorded. Patients were classified into low-risk and intermediate/high-risk groups. In the intermediate/high-risk group, the PRIMARY score was 1–2 in 17.6

Germ cell neoplasia in situ (GCNIS)-associated tumors encompass both seminomatous and non-seminomatous germ cell tumors (NSGCT), with teratoma being a subtype of NSGCT [1]. Growing teratoma syndrome (GTS) is a rare benign tumor that manifests as metastases of the teratoma component in patients with germ cell tumors, despite the normalization of tumor markers during and after chemotherapy. It has three main components: clinical enlargement of tumors during or after chemotherapy, normalization of previously elevated tumor markers, and presence of only mature elements upon histologic examination of the tumor [2]. The diagnosis is established by sequential radiological imaging and the presence of mature teratoma remnants in the surgical specimen. These growing teratomas are resistant to chemotherapy and radiation therapy, therefore extensive surgeries may be needed [3]. Patients with disease on imaging, even if stable, should continue to be followed as these lesions can begin to grow even years later [4]. We present a rare case of testicular-derived GTS identified by F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and confirmed by histopathology.

Introduction and objective: Prediction of the pathologic response to neoadjuvant chemotherapy (NAC) in patients with locally advanced breast cancer is essential for optimal treatment strategy. The current approach of adjuvant or neoadjuvant treatment is based on the molecular subtype. Obesity may have affected chemotherapy response. This study aims to evaluate the relationship between metabolic activity of adipose tissue (AT) and pathological responses to NAC. And to define the association with body mass index (BMI) and metabolic parameters of standardized uptake value (SUV) of adipose tissue measured by positron emission computed tomography (PET/CT). Material and methods: One-hundred and sixteen consecutive patients with stage II and III breast cancer who underwent PET/CT before receiving NAC, were evaluated in the study. Metabolic parameters of visceral adipose tissue (VAT-SUV), subcutaneous adipose tissue (SAT-SUV), and calculated SUV of visceral-to-subcutaneous ratio (V/S-ratio) were regarded. The relationship between SUV of AT and pathologic response was evaluated from medical records retrospectively.

La respuesta histopatológica a la quimioterapia neoadyuvante (NAC) es esencial en pacientes con cáncer de mama. La predicción de la respuesta histopatológica a la NAC en pacientes con cáncer de mama localmente avanzado es esencial para una estrategia de tratamiento óptima. El enfoque actual del tratamiento adyuvante o neoadyuvante se basa en el subtipo molecular. La obesidad puede afectar la respuesta a la quimioterapia. El objetivo de este estudio es evaluar la relación entre la actividad metabólica del tejido adiposo (AT) y la respuesta histopatológica de la NAC. Definir, la asociación del índice de masa corporal (IMC) y el valor del «Standard Uptake Value» (SUV) de AT medido por tomografía por emisión de positrones (PET/TC) con la respuesta a la quimioterapia neoadyuvante. Hemos incluido 116 pacientes consecutivos con cáncer de mama, estadio II y III, que acudieron para la realización de un PET/TC previo a NAC entre 2016 y 2020. Hemos calculado los parámetros metabólicos del tejido adiposo visceral (SUV del VAT), del tejido adiposo subcutáneo (SUV del SAT) y la relación entre ambos (relación V/S). Todos estos biomarcadores los hemos relacionado con la respuesta histopatológica de los pacientes. El análisis univariante muestra una correlación significativa entre la respuesta histopatológica con el estadio clínico (p < 0,001), HER2 positivo (p < 0,001), SUV del VAT (p = 0,037), densidad del VAT (p = 0,043) y la relación V/S (p = 0,003). El análisis multivariante muestra una significación estadística entre HER2 positivo y la relación V/S con la respuesta histopatológica. Se evidencia una correlación positiva del IMC con el volumen del IVA (p < 0,001), SUV del IVA (p < 0,016), volumen del SAT (p < 0,001) y el SUV del SAT (p < 0,001). Se evidencia una correlación negativa del IMC con la relación V/S (p = 0,039) y la densidad del SAT (p = 0,003). La actividad metabólica de AT se correlaciona con el IMC y la respuesta a la quimioterapia. La relación V/S baja se asocia a IMC alto y mal pronóstico, por lo que puede ser un marcador útil en la predicción de la respuesta a la NAC en pacientes con cáncer de mama localmente avanzado. Prediction of the pathologic response to neoadjuvant chemotherapy (NAC) in patients with locally advanced breast cancer is essential for optimal treatment strategy. The current approach of adjuvant or neoadjuvant treatment is based on the molecular subtype. Obesity may have affected chemotherapy response. This study aims to evaluate the relationship between metabolic activity of adipose tissue (AT) and pathological responses to NAC. And to define the association with body mass index (BMI) and metabolic parameters of standardized uptake value (SUV) of adipose tissue measured by positron emission computed tomography (PET/CT). One-hundred and sixteen consecutive patients with stage II and III breast cancer who underwent PET/CT before receiving NAC, were evaluated in the study. Metabolic parameters of visceral adipose tissue (VAT-SUV), subcutaneous adipose tissue (SAT-SUV), and calculated SUV of visceral-to-subcutaneous ratio (V/S-ratio) were regarded. The relationship between SUV of AT and pathologic response was evaluated from medical records retrospectively. Univariate-analysis revealed that good pathological response was significantly associated with clinical stage (p < 0.001), HER-2 positivity (p < 0.001), VAT-SUV (p = 0.037), VAT-density (p = 0.043) and V/S-ratio (p = 0.003). In multivariate-analysis clinical stage, HER-2 positivity and V/S-ratio were found to have statistically effect on pathological response. VAT-volume (p < 0.001), VAT-SUV (p = 0.016), SAT-volume (p < 0.001) and SAT-SUV (p < 0.001) has positive correlation with BMI value. On the other hand, V/S-ratio (p = 0.039) and SAT-density (p = 0.003) has negative correlation with BMI. Metabolic activity of AT is associated with BMI and effected chemotherapy responses. Low V/S ratio was associated with high BMI and poor pathological response to NAC. V/S ratio may be a useful marker for the prediction of NAC responses.