Clinical Nuclear Medicine

Limited Usefulness of 18F-FDG PET/CT in Predicting Tumor Regression After Preoperative Chemotherapy for Noncardia Gastric Cancer: The Italian Research Group for Gastric Cancer (GIRCG) Experience Background The present study aimed to better define the usefulness of 18F-FDG PET/CT in predicting pathological tumor response (PTR) and survival in patients with noncardia gastric cancer treated with preoperative chemotherapy. Methods Seventy-one patients were recruited in 6 Italian centers. The SUV of 18F-FDG PET/CT was measured at baseline and after treatment, and the difference (dSUV) was computed. The association between PET indexes and PTR, assessed by the Becker score, was evaluated by nonparametric regression. The discriminant power of PET indexes with respect to the absence of PTR (Becker 2/3) was studied by receiver operating characteristic (ROC) curve and synthesized by the area under the curve (ROC-AUC). Results dSUV allowed to partially discriminate between absence/presence of PTR, when expressed as either absolute value (ROC-AUC, 0.73; 95% confidence interval, 0.59–0.87) or percentage (ROC-AUC, 0.74; 95% confidence interval, 0.59–0.89). However, only extreme values of percent dSUV were really informative. All 7 patients whose 18F-FDG uptake had increased despite preoperative treatment showed no tumor regression at pathologic examination. Seven of the 10 patients whose metabolic response had been 70% or greater had complete or nearly complete pathologic tumor regression (Becker score 1a or 1b). The metabolic response of the remaining 54 patients, which ranged between 0% and 70%, did not permit to reliably forecast pathologic tumor regression. Survival significantly decreased with increasing Becker score but was unaffected by metabolic response. Conclusions The present study suggests that 18F-FDG PET/CT has limited usefulness in predicting cancer regression. The lack of metabolic response in serial measurements indicates the probable ineffectiveness of preoperative treatment.

Prognostic Value of 18F-FDG PET/CT—Metabolic Parameters at Baseline and Interim Assessment in Pediatric Anaplastic Large Cell Lymphoma Introduction The event-free survival in pediatric anaplastic large cell lymphoma (ALCL) remains at 70% irrespective of the diverse chemotherapy regimens used. There is lack of valid prognostic factors identifying high-risk patients. We investigated the prognostic value of baseline metabolic parameters and interim response on 18F-FDG PET/CT in pediatric ALCL patients. Methods We retrospectively reviewed 40 pediatric ALCL patients with paired 18F-FDG PET/CT and treated uniformly on vinblastine-based institution protocol. The SUVmax, SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis of the lymphomatous lesion were measured. Continuous PET parameters were stratified by their median values. Deauville scoring system was used to assess response to chemotherapy in the interim scan. Prognostic factors for overall survival (OS) and disease-free survival (DFS) were estimated using the Kaplan-Meier method, log-rank test, and Cox proportional hazards model. Results At median follow-up of 52 months, 13 patients died and 13 had recurrence. On univariate analysis, higher whole-body MTV (WBMTV) and partial response on interim scan were statistically associated with OS. High-risk features, WBMTV, and partial response were statistically associated with DFS. On multivariate analysis combining baseline characteristics and interim response, interim response (hazard ratio, 3.56; P = 0.034) was statistically significant for OS. Multivariate analysis for DFS using only baseline characteristics revealed WBMTV as statistically significant (hazard ratio, 4.08; P = 0.035), but none of the parameters was statistically significant when baseline characteristics and interim response were evaluated together. Conclusions Whole-body tumor burden assessment with MTV and interim response may help to identify high-risk patients who might get benefitted from intensive therapy.

Comparison of 18F-FDG PET/CT Criteria for the Prediction of Therapy Response and Clinical Outcome in Patients With Metastatic Melanoma Treated With Ipilimumab and PD-1 Inhibitors Immunotherapy currently represents one of the most effective therapies in metastatic melanoma. However, its indirect antineoplastic activity through the immune system has raised relevant challenges for diagnostic imaging in the evaluation of the response to treatment. Purpose The aim of this retrospective study was to compare the diagnostic accuracy of different 18F-FDG PET/CT criteria to predict therapy response and clinical outcome in melanoma patients treated with immune checkpoint inhibitors. Patients and Methods Fifty-seven patients with metastatic melanoma treated with ipilimumab (n = 25; group 1) or with PD-1 inhibitors (n = 32; group 2) who performed an 18F-FDG PET/CT scan before treatment (PET0) and 12 to 18 weeks later (PET1) were retrospectively evaluated. Response at PET1 was evaluated according to RECIST 1.1, EORTC, PERCIMT (PET Response Evaluation Criteria for Immunotherapy), and by percentage change of metabolic tumor volume (MTV) and total lesion glycolysis of up to 5 target lesions. Performance of each criterion at PET1 to predict clinical benefit at 6 months since starting immunotherapy was assessed and correlated to progression-free survival. Results In group 1, the best predictor of therapy response was MTV combined with PERCIMT criteria (accuracy, 0.96). In group 2, overlapping results were found for EORTC, MTV, and total lesion glycolysis (accuracy, 0.97). The reliability of the above parameters was also confirmed in the progression-free survival analysis. Conclusions 18F-FDG PET/CT performed after 3 to 4 months since starting immunotherapy can correctly evaluate response to treatment and can also able to predict long-term clinical outcome. Performance of 18F-FDG PET/CT and criteria for response assessment is influenced by the class of treatment.

Prostate-Specific Membrane Antigen Expression in Primary Juvenile Nasal Angiofibroma—A Pilot Study Purpose Prostate-specific membrane antigen (PSMA) is highly expressed in prostate cancer cells and is exploited for imaging and treatment of patients with prostate cancer. Prostate-specific membrane antigen expression is also demonstrated in the tumor-associated neovasculature endothelium. Juvenile nasal angiofibroma (JNA), being a similar highly vascular tumor, may also demonstrate significant PSMA expression, which may be utilized for its imaging and treatment. Methods In this prospective study, 25 clinicoradiologically diagnosed primary JNA patients underwent PSMA PET/CT scan. The scan was performed after 45 to 60 minutes of intravenous injection of 2 to 3 mCi (74–111 MBq) of 68Ga-PSMA-HBED-CC on a dedicated PET/CT scanner. Low-dose CT scan was acquired from vertex to sternoclavicular joint (100 mA, 20 kVp, 3-mm slice thickness, 0.8 pitch). Images were reconstructed with iterative reconstruction technique (4 iterations, 24 subsets). The objective was to assess the intensity and pattern of PSMA uptake in primary JNA patients. Results All cases (n = 25) of primary JNA showed PSMA expression in the tumor (100%). The median PSMA SUVmax ratio of tumor to background was 4.57 (range, 2.08–7.27). Intracranial extension in 14 of 25 patients was prominently visualized because of absence of background uptake in the brain. Advanced stage tumors demonstrated greater uptake than early tumors (P = 0.011). A statistically nonsignificant trend was noted for decreasing uptake with increasing age after normalizing for stage (Spearman correlation coefficient r = −0.08). Conclusions Assessment of PSMA expression in JNA by PSMA PET/CT opens up a new window of opportunity with respect to its radiological staging, vascularity assessment, and molecular characterization. A potential role in identification of the difficult residual-recurrent disease is anticipated and perhaps also in radioligand therapy for residual/recurrent JNA. Clinical Trials Registry of India (CTRI/2018/08/015479).

Quality and Safety in Healthcare, Part LVI: Wellness Leaders All members of the healthcare system should make positive contributions to improve the overall level of wellness. However, leaders should have certain specific responsibilities to prevent burnout and increase happiness and wellness at work. It has been proposed that a chief wellness officer direct the initiatives to improve wellness, in collaboration with many others including those in the executive suite. Part of improving joy in the workplace is improving efficiency, quality care for patients, safety for patients and workers, meaningful work for the workers, and respect and fairness for all.

Posterior Reversible Encephalopathy Syndrome After 90Y-Resin Microspheres Radioembolization A 66-year-old man with colorectal carcinoma and liver-only metastases underwent radioembolization using 90Y-loaded, resin-based microspheres. One day after radioembolization, the patient experienced severe hypertension and multiple seizures. On MRI, symmetric edematous areas in the cerebellum and the parietal and occipital lobe were observed, a typical finding for posterior reversible encephalopathy syndrome (PRES). The PRES is associated with, for example, renal failure or blood pressure fluctuations leading to cerebral endothelial dysfunction. Antihypertensive and antiepileptic therapies led to normotensive blood pressure and neurological remission. Therefore, newly developed neurological symptoms accompanied by high blood pressure fluctuations after radioembolization should lead to PRES as differential diagnosis.

Role of 68Ga–Prostate-Specific Membrane Antigen PET/CT in Disease Assessment in Glioblastoma Within 48 Hours of Surgery Within 48 hours after surgery, disease assessment in glioblastoma is a challenge for both the clinician and the radiologist. Certain technical and logistical issues prevail in this period. 68Ga–prostate-specific membrane antigen PET/CT is a known molecular imaging marker in prostate cancer. Its role in high-grade gliomas has been recently discussed. We present a case of a 39-year-old man with recurrence glioblastoma of the right frontal lobe and underwent resurgery. After surgery, 68Ga–prostate-specific membrane antigen PET/CT showed residual disease along the posterior and inferior margin of the postoperative cavity.

The Great Mimicker—Tuberculosis Involving Prostate and Vertebrae Posing as Metastatic Prostate Carcinoma on FDG PET/CT A 65-year-old man underwent FDG PET/CT for evaluation of vertebral lesions, radiologically suspected to be metastases. The scan showed hypermetabolism in D8 to D9 vertebrae, retroperitoneal lymph nodes, and both the lobes of prostate. Transrectal ultrasound-guided biopsy of prostate was performed with suspicion of prostate malignancy. The biopsy revealed caseating granulomatous lesions in prostate suggestive of tuberculosis. Post antitubercular treatment patient showed excellent clinical response. Possibility of infective pathologies mimicking malignancy should be kept in mind while evaluating hypermetabolic foci seen on PET/CT. Although rare, tuberculosis of prostate needs consideration in differential diagnosis of FDG-avid foci seen in prostate.

18F-FDG PET/CT Evaluation of Crizotinib and Lorlatinib Therapy in Metastatic ROS-1–Positive Non–Small Cell Lung Cancer ROS-1–positive non–small cell lung cancers (NSCLCs) are rare (approximately 1% of all NSCLCs) and require a first-line treatment by crizotinib. Crizotinib resistance is frequent within the first 12 months of treatment. Lorlatinib is a novel tyrosine kinase inhibitor of ROS-1 recently indicated for metastatic or locally advanced crizotinib-resistant NSCLC. We report the use of lorlatinib as second-line with a complete tumoral response after only 3 months of treatment. This case shows the major role of 18F-FDG PET/CT in treatment evaluation and monitoring targeted therapy in metastatic NSCLC.

The Hot Pleura: Isolated Pleural Metastases From Renal Cell Carcinoma Renal cell carcinoma (RCC) is the most common solid renal malignancy that metastasizes typically to lungs, bones, liver, adrenals, and lymph nodes. Isolated pleural metastases of RCC are extremely rare, with only few cases reported in the literature. We report one such case of a 60-year-old woman, a known case of RCC of the left kidney who underwent nephrectomy, and on follow-up, PET/CT scan revealed diffuse thick nodular hypermetabolic left pleural thickening, which was later biopsied and turned out to be pleural metastases from RCC. No other site of metastases was found.