Impact of baseline and interim quantitative PET parameters on outcomes of classical Hodgkin Lymphoma.

Currently, analysis of interim PET (iPET) according to the Deauville score (DS) is the most important predictive factor in Hodgkin lymphoma (HL); however, there is room for improvement in its prognostic power. This study aimed to evaluate the prognostic value of quantitative PET analysis (maximum standard uptake value [SUVmax], total metabolic tumor volume [TMTV] and total lesion glicolysis [TLG]) at baseline (PET0) and iPET in a retrospective cohort of newly diagnosed classical HL. For positive iPET (+ iPET), the reduction of quantitative parameters in relation to PET0 (ΔSUVmax, ΔTMTV and ΔTLG) was calculated. Between 2011 and 2017, 234 patients treated with ABVD were analyzed. Median age was 30 years-old, 59% had advanced stage disease, 57% a bulky mass and 25% a + iPET (DS 4-5). At baseline, high TLG was associated with an increased cumulative incidence of failure (CIF) (p = 0.032) while neither SUVmax, TMTV or TLG were associated with overall survival (OS) or progression-free survival (PFS). In multivariate analysis, only iPET was associated with CIF (p < 0.001). Among ΔSUVmax, ΔTMTV and ΔTLG, only a ΔSUVmax ≥ 68.8 was significant for PFS (HR: 0.31, CI95%: 0.11-0.86, p = 0.024). A subset of patients with improved PFS amongst + iPET was identified by the quantitative (ΔSUVmax ≥ 68.8%) analysis. In this real-world Brazilian cohort, with prevalent high-risk patients, quantitative analysis of PET0 did not demonstrate to be prognostic, while a dynamic approach incorporating the ΔSUVmax to + iPET succeeded in refining a subset with better prognosis. These findings warrant validation in larger series and indicate that not all patients with + iPET might need treatment intensification.

Survival and Response Outcomes for Gastrointestinal Neuroendocrine Tumor (GEP-NETs) Patients Treated with Lutetium-177-DOTATATE in a Brazilian Reference Center: A Six-Year Follow-Up Experience.

BACKGROUND: PRRT can be an option for all-grade GEP-NETs, but selecting patients is challenging. In this scenario, clinical-pathological and radiological characteristics, such as pre-treatment Ga-68 DOTA PET/CT, might have the potential to help. METHODS: A retrospective chart review was conducted on advanced GEP-NETs treated with at least one PRRT dose. Overall survival (OS) and progression-free survival (PFS) were calculated using the Kaplan-Meier method. Krenning Score (KS), and the maximum standardized uptake value (SUVmax) were derived from the pre-treatment scans. A maximally selected rank statistics test was used for SUVmax simple cut point estimate. RESULTS: Among 36 patients, 19 had primary pancreatic tumors. The numbers of G1, G2, and G3 tumors were 10, 18, and 7, respectively. During a median follow-up of 90.5 months, 4 patients died. Median OS was not reached for G1 and G2 tumors, and it was 30 months for G3 (p = 0.001). Median PFS was 23 months, with G3 showing lower PFS compared to G1 [7 versus 30 months; HR 8.41 (95%CI 2.2-31.0; p = 0.001)]. CONCLUSIONS: PRRT provides long-term PFS in patients with G1/G2 GEP-NETs independent of clinical characteristics and primary site. G3 has worse survival, but selected patients may experience long OS after PRRT treatment.

Impressive response to dabrafenib, trametinib, and osimertinib in a metastatic EGFR-mutant/BRAF V600E lung adenocarcinoma patient.

The survival outcomes of the FLAURA trial support osimertinib as the new standard of care for untreated patients harboring activating mutations in the epidermal growth factor receptor (EGFR). Despite the initial response, disease progression invariably occurs. Although uncommon, BRAF V600E mutation arises as a unique mechanism of resistance, and thus far, no prospective studies are available to support concurrent EGFR/BRAF blockade. We report a case of impressive radiological and ctDNA response under dabrafenib, trametinib, and osimertinib in an advanced EGFR-mutant lung adenocarcinoma patient who developed BRAF V600E as one of the acquired resistance mechanisms to second-line osimertinib. Moreover, the patient experienced remarkable clinical improvement and good tolerance to combination therapy. The present case suggests the importance of prospective studies evaluating both efficacy and safety of the combination in later line settings and points towards the potential of ctDNA to monitor resistance mechanisms and treatment benefit in clinical practice.

Nonprostatic diseases on PSMA PET imaging: a spectrum of benign and malignant findings.

PSMA PET imaging was originally used to assess biochemical recurrence of prostate cancer (PCa), but its clinical use was promptly extended to detection, staging and therapy response assessment. The expanding use of PSMA PET worldwide has also revealed PSMA ligand uptake in diverse nonprostatic diseases, which raised questions about the specificity of this imaging modality. Although not very common initially, a growing number of pathologies presenting PSMA uptake on PET have been reported in the last few years, and a proper interpretation of PSMA PET imaging findings suddenly became challenging and, to some extent, confusing. Compared to cytoplasmic PSMA expression in nonprostatic cells, the molecular features of apical PSMA expression in PCa cells can help to distinguish these various conditions. Correlations of imaging findings to patient history, to the expected pattern of disease spread and mainly to computed tomography (CT) and/or magnetic resonance imaging (MRI) characteristics will reinforce the distinction of lesions that are more likely related to PCa from those that could lead to an incorrect diagnosis. The overall benefits of endothelial PSMA expression, which is associated with the neovasculature of malignant neoplasms, will be highlighted, stating the potential use of PSMA ligand uptake as a theranostic tool. This review aims to cover the collection of nonprostatic diseases, including benign and malignant tumors, in a didactic approach according to disease etiology, with discussion of bone-related conditions and inflammatory and infectious processes.

Clinical perspectives of PSMA PET/MRI for prostate cancer.

Prostate cancer imaging has become an important diagnostic modality for tumor evaluation. Prostate-specific membrane antigen (PSMA) positron emission tomography (PET) has been extensively studied, and the results are robust and promising. The advent of the PET/magnetic resonance imaging (MRI) has added morphofunctional information from the standard of reference MRI to highly accurate molecular information from PET. Different PSMA ligands have been used for this purpose including 68gallium and 18fluorine-labeled PET probes, which have particular features including spatial resolution, imaging quality and tracer biodistribution. The use of PSMA PET imaging is well established for evaluating biochemical recurrence, even at low prostate-specific antigen (PSA) levels, but has also shown interesting applications for tumor detection, primary staging, assessment of therapeutic responses and treatment planning. This review will outline the potential role of PSMA PET/MRI for the clinical assessment of PCa.

Fluorodeoxyglucose-positron emission tomography staging can replace bone marrow biopsy in Hodgkin's lymphoma. Results from Brazilian Hodgkin's Lymphoma Study Group

ABSTRACT Objective: To investigate, in a large prospective multicenter study, whether 2-[18F]-fluoro-2-deoxy-D-glucose-positron emission tomography is sufficiently accurate to identify clinically important bone marrow involvement by Hodgkin's lymphoma to replace routine bone marrow biopsy in a developing tropical country. Methods: Patients newly diagnosed with Hodgkin's lymphoma were recruited from six cancer centers in Brazil. All were staged by the results of positron emission tomography/computed tomography that were centrally reviewed and by iliac crest bone marrow biopsy. Patients were classified as having marrow disease if they had lymphoma identified by marrow biopsy histology or had focal 2-[18F]-fluoro-2-deoxy-D-glucose marrow uptake that resolved following chemotherapy. Results: A total of 246 participants were recruited from six different centers and 62 (25.2%) were judged to have Hodgkin's lymphoma in the bone marrow. Positron emission tomography and biopsies were concordant in 206 patients (83%). Positron emission tomography correctly identified marrow disease in 59/62 patients (95.1%) and marrow biopsy in 25/62 patients (40.3%). In 22/62 (35.4%) patients, the two techniques were concordant in the diagnosis of marrow involvement. Of the forty discordant results, positron emission tomography found bone marrow involvement in 37 patients, upstaging 22 to stage IV and having an impact on therapeutic decision in nine cases given their reallocation from early to advanced stage. Three false negative positron emission tomography results were obtained with bone marrow biopsy giving positive findings. All three cases were classified as stage IV regardless of bone marrow findings implying no modification in the clinical management. The sensitivity, specificity and accuracy of positron emission tomography for detecting bone marrow disease were 95%, 100% and 98% and for bone marrow biopsy they were 40%, 100% and 84%, respectively. Conclusion: We conclude that positron emission tomography can replace marrow biopsy in Brazilian patients with Hodgkin's lymphoma without compromising clinical management.

Fluorodeoxyglucose-positron emission tomography staging can replace bone marrow biopsy in Hodgkin's lymphoma. Results from Brazilian Hodgkin's Lymphoma Study Group.

OBJECTIVE: To investigate, in a large prospective multicenter study, whether 2-[18F]-fluoro-2-deoxy-d-glucose-positron emission tomography is sufficiently accurate to identify clinically important bone marrow involvement by Hodgkin's lymphoma to replace routine bone marrow biopsy in a developing tropical country. METHODS: Patients newly diagnosed with Hodgkin's lymphoma were recruited from six cancer centers in Brazil. All were staged by the results of positron emission tomography/computed tomography that were centrally reviewed and by iliac crest bone marrow biopsy. Patients were classified as having marrow disease if they had lymphoma identified by marrow biopsy histology or had focal 2-[18F]-fluoro-2-deoxy-d-glucose marrow uptake that resolved following chemotherapy. RESULTS: A total of 246 participants were recruited from six different centers and 62 (25.2%) were judged to have Hodgkin's lymphoma in the bone marrow. Positron emission tomography and biopsies were concordant in 206 patients (83%). Positron emission tomography correctly identified marrow disease in 59/62 patients (95.1%) and marrow biopsy in 25/62 patients (40.3%). In 22/62 (35.4%) patients, the two techniques were concordant in the diagnosis of marrow involvement. Of the forty discordant results, positron emission tomography found bone marrow involvement in 37 patients, upstaging 22 to stage IV and having an impact on therapeutic decision in nine cases given their reallocation from early to advanced stage. Three false negative positron emission tomography results were obtained with bone marrow biopsy giving positive findings. All three cases were classified as stage IV regardless of bone marrow findings implying no modification in the clinical management. The sensitivity, specificity and accuracy of positron emission tomography for detecting bone marrow disease were 95%, 100% and 98% and for bone marrow biopsy they were 40%, 100% and 84%, respectively. CONCLUSION: We conclude that positron emission tomography can replace marrow biopsy in Brazilian patients with Hodgkin's lymphoma without compromising clinical management.

Brain Metastasis of Medullary Thyroid Carcinoma Without Macroscopic Calcification Detected First on 68Ga-Dotatate and Then on 18F-Fluoride PET/CT.

We report a case of a medullary thyroid carcinoma noncalcified brain metastasis characterized on Ga-dotatate PET/CT but not on an F-fluoride PET/CT performed 1 month later. Subsequent F-fluoride PET/CT studies performed 7 and 19 months after the Ga-dotatate PET/CT study demonstrated focal uptake in the metastasis. The CT images of the last PET/CT study also depicted a small focus of calcification beginning in the metastatic site.

Iodine/FDG "Flip-Flop" Phenomenon Inside a Large Metastatic Thyroid Cancer Lesion Better Characterized on SPECT/CT and PET/CT Studies.

Iodine/FDG "flip-flop" phenomenon inside large metastatic thyroid cancer lesions has been rarely described. We present a case of this phenomenon better characterized using SPECT/CT and PET/CT studies.

Clinical perspectives of PSMA PET/MRI for prostate cancer

Prostate cancer imaging has become an important diagnostic modality for tumor evaluation. Prostate-specific membrane antigen (PSMA) positron emission tomography (PET) has been extensively studied, and the results are robust and promising. The advent of the PET/magnetic resonance imaging (MRI) has added morphofunctional information from the standard of reference MRI to highly accurate molecular information from PET. Different PSMA ligands have been used for this purpose including 68gallium and 18fluorine-labeled PET probes, which have particular features including spatial resolution, imaging quality and tracer biodistribution. The use of PSMA PET imaging is well established for evaluating biochemical recurrence, even at low prostate-specific antigen (PSA) levels, but has also shown interesting applications for tumor detection, primary staging, assessment of therapeutic responses and treatment planning. This review will outline the potential role of PSMA PET/MRI for the clinical assessment of PCa.

SUV Normalized by Skeletal Volume on 18F-Fluoride PET/CT Studies.

OBJECTIVE: To propose a technique for SUV normalization on F-fluoride PET/CT (F-NaF) studies based on skeletal volume and to compare the SUVs normalized by this technique with the ones normalized by body weight. METHODS: SUVs were obtained in volumes of interest (VOIs) in proximal diaphyseal regions of the right humerus (HD) and right femur (FD) in 12 selected F-NaF studies. The 12 studies presented both regions considered normal by visual examination on PET and CT and were performed in patients presenting body weight below 50 kg (B50) or above 90 kg (A90) (6 patients in each group). The maximum SUVs were calculated in these 2 bone regions in both groups of patients using body weight (SUV BW) and skeletal volume (SUV SV) methodologies. The total skeletal volume for each patient was estimated based on whole skeletal VOIs automatically defined on the CT component of the PET/CT study. The maximum SUVs calculated using the 2 methodologies were compared. RESULTS: The maximum SUVs BW were statistically higher in the group A90 in both regions, with a P < 0.001 and P < 0.008 for FD and HD, respectively. The maximum SUVs SV in the 2 regions were not statistically different between the groups B50 and A90, P values of 0.27 and 0.87 for FD and HD, respectively. CONCLUSIONS: The SUVs normalized by skeletal volume present similar results in groups of patients with extremes of body weight. Therefore, this methodology could be more adequate than the one normalized by body weight to semiquantitatively analyze F-NaF studies.

Visualization of Lymph Nodal and Hepatic Metastases of Medullary Thyroid Carcinoma on 18F-Fluoride PET/CT.

F-fluoride uptake in soft tissue metastases has been previously described. Herein, we report a case of F-fluoride uptake in lymph nodal and hepatic metastases of medullary thyroid carcinoma. Simultaneous CT showed calcified lesions in these regions.