Prostate Adenocarcinoma Metastasis to the Rectal Submucosa and Mesorectal Lymph Node on 18 F-PSMA PET/CT.

ABSTRACT: We report a case of biopsy-proven prostate cancer metastasis to the rectum and presumed metastasis to a mesorectal lymph node, identified as radiotracer-avid lesions on prostate-specific membrane antigen PET/CT during workup for biochemically recurrent prostate cancer. This case adds to a growing number of atypical sites of metastatic prostate cancer being reported since the approval of prostate-specific membrane antigen PET/CT for staging of prostate cancer.

Long-term outcomes and predictors of early response, late relapse, and survival for patients treated with bispecific LV20.19 CAR T-cells.

We previously reported results of a first-in-human trial of bispecific LV20.19 chimeric antigen receptor T-cell (CAR-T) therapy, demonstrating high response rates in patients with relapsed, refractory (R/R) B-cell malignancies. We now report two-year survival outcomes and predictors of early response, late relapse, and survival. Patients from the previously reported phase 1 dose escalation and expansion trial of LV20.19 CAR-T therapy (NCT03019055) treated at target dose of 2.5 × 106 cells/kg (n = 16) were included in this updated analysis. Two-year progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan-Meier method. The relationship of in-vivo CAR-T expansion, tumor burden, and effector: target ratio on early response (day 28) and late relapse (>180 days post-CAR-T) were assessed. Exact log-rank testing was performed to evaluate the impacts of clinical variables on survival outcomes. With a median of 31 months (range 27-40) of follow-up, two-year PFS and OS were 44% and 69%. Median PFS and OS were 15.6 months and not reached, respectively. For CAR-naïve large B-cell lymphoma patients (n = 8), two-year PFS and OS were 50% and 75%. No patient with progression experienced dual target antigen (CD19 or CD20) loss on post-relapse biopsy. Lower in vivo expansion was strongly associated with late relapse. Early treatment response was impeded by high metabolic tumor volume and low effector: target ratio. Bridging therapy and higher absolute lymphocyte count on day of CAR-T infusion were associated with inferior survival outcomes. In conclusion, this initial trial of LV20.19 CAR-T demonstrates a signal for favorable long-term outcomes for patients with R/R B-cell malignancies.

Value of Pretreatment 18F-fluorodeoxyglucose Positron Emission Tomography in Patients With Localized Pancreatic Cancer Treated With Neoadjuvant Therapy.

Background: 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) imaging is not routine in patients with localized pancreatic cancer (PC). We evaluated the prognostic value of PET/CT in patients who received neoadjuvant therapy. Methods: Patients with localized PC underwent pretreatment PET/CT with or without posttreatment (preop) PET/CT. Maximum standardized uptake values (SUV) were classified as high or low based on a cut point of 7.5 at diagnosis (SUVdx) and 3.5 after neoadjuvant therapy (preoperative; SUVpreop). Preop carbohydrate antigen 19-9 (CA19-9) was classified as normal ( ≤ 35 U/mL) or elevated. Results: Pretreatment PET/CT imaging was performed on 201 consecutive patients; SUVdx was high in 98 (49%) and low in 103 (51%). Preop PET/CT was available in 104 (52%) of the 201 patients; SUVpreop was high in 60 (58%) and low in 44 (42%). Following neoadjuvant therapy, preop CA19-9 was normal in 90 (45%) patients and elevated in 111 (55%). Median overall survival (OS) of all patients was 27 months; 33 months for the 103 patients with a low SUVdx and 22 months for the 98 patients with a high SUVdx (p = 0.03). Median OS for patients with low SUVdx/normal preop CA19-9, high SUVdx/normal preop CA19-9, low SUVdx/elevated preop CA19-9, and high SUVdx/elevated preop CA19-9 were 66, 34, 23, and 17 months, respectively (p < 0.0001). OS was 44 months for the 148 (74%) patients who completed all intended neoadjuvant therapy and surgery and 13 months for the 53 (26%) who did not undergo surgery (p < 0.001). Conclusion: Pretreatment PET/CT avidity and preop CA19-9 are clinically significant prognostic markers in patients with PC.

68Ga-DOTATATE positron emission tomography/computed tomography to detect the recurrence of phosphaturic mesenhcymal tumor-induced osteomalacia.

68Ga-DOTATATE positron emission tomography/computed tomography (PET/CT) has shown superiority over 111Indium-octreotide scanning for the detection of phosphaturic mesenchymal tumors (PMTs). We report a case of tumor-induced osteomalacia resulting from PMT which, although initially clinically suspected, was not localized on octreotide scintigraphy performed several years prior. Subsequent surgical excision of a presumed benign osseous lesion a few years later revealed the diagnosis on pathology. Imaging assessment using 68Ga-DOTATATE PET/CT following recent clinical suspicion for recurrence revealed an intense tracer-avid lesion at the primary tumor site. DOTATATE imaging plays an important role in localizing tumors with high somatostatin receptor expression, such as neuroendocrine tumors (pheochromocytoma, paraganglioma, and neuroblastoma), meningioma, and mesenchymal tumors, causing oncogenic osteomalacia.

SPECT/CT Detection of a Communicating Arachnoid Cyst in a Patient With Normal Pressure Hydrocephalus.

A 59-year-old man with history of multiple sclerosis and residual sensory and motor dysfunction presented with progressive lower-extremity weakness, ataxic gait, and intermittent urinary incontinence. Brain MRI demonstrated volume loss with disproportionate ventricular dilatation, but no evidence of infarction or abnormal enhancement. Radionuclide cisternography showed early and persistent ventricular reflux, poor progression of radiopharmaceutical over convexities, and delayed clearance in a pattern consistent with normal pressure hydrocephalus. Asymmetric activity in the right parietal region was also identified. Fused SPECT/CT, as well as fusion of the SPECT with a previous brain MRI, demonstrated a communicating arachnoidal cyst.