Vienna, Austria

ESTRO 2023

Session Item

Poster (Digital)
PSMA PET imaging of non-acinar histological variants of prostate cancer
Comron Hassanzadeh, USA


PSMA PET imaging of non-acinar histological variants of prostate cancer

Comron Hassanzadeh1, Gregory Ravizzini2, Brian Chapin3, Ana Aparicio4, Tharakeswara Bathala5, Devaki Shilpa Surasi2, Chad Tang1

1The University of Texas MD Anderson, Radiation Oncology, Houston, USA; 2The University of Texas MD Anderson, Nuclear Medicine, Houston, USA; 3The University of Texas MD Anderson, Urology, Houston, USA; 4The University of Texas MD Anderson, Medical Oncology, Houston, USA; 5The University of Texas MD Anderson, Diagnostic Imaging, Houston, USA

Show Affiliations
Purpose or Objective

Prostate-specific membrane antigen-targeted positron emission tomography (PSMA-PET) has become widely adopted in the settings of biochemically recurrent and metastatic prostate cancer. However, roughly 20% of patients with biochemical recurrence have PSMA-PET negative disease. Limited data exists to identify characteristics that predispose to PSMA occult prostate cancer. Non-acinar histological variants such as ductal adenocarcinoma (DAC) and neuroendocrine prostate cancer (NEPC) are associated with poorer outcomes and may remain undetectable using PSMA diagnostic imaging. Conflicting case reports have challenged the ability of PSMA-PET to accurately identify lesions in patients with histological variants. We analyzed the effect of non-acinar histology on PSMA-PET radiotracer, [18F]DCFPyL radiographic findings.

Material and Methods

Patients who underwent [18F]DCFPyL PSMA-PET/CT imaging at a single institution from 8/2021 to 8/2022 were reviewed. Among these, 21 patients with non-acinar histology were included for analysis. Patient and clinical characteristics were collected and compared with PSMA-PET imaging findings. Chi square analysis was used to evaluate the association of clinical features with PSMA-PET results.


Among 21 patients, 14 patients (67%) had DAC while 7 patients (33%) had NEPC. Median age of diagnosis was 63 years (range, 49-79). Reason for undergoing PSMA-PET included surveillance after biochemical recurrence (12 patients), assessing response with metastatic disease (8 patients), and initial staging in localized high risk prostate cancer (1 patient). Median injected dose was 9.3 mCi (range, 5.5-9.9) while median uptake time was 60 minutes (range, 55- 80). Median PSA at time of PSMA-PET was 1.8 ng/mL (range, 0-221.3), with 7 patients (33%) on active ADT at time of PSMA-PET. PSMA-PET was positive in 16 patients (76%) and negative in 5 patients. Among the 5 patients with PSMA-PET occult disease, 5 had DAC and 1 had NEPC with a median PSA of 0.5 (range, 0-1.8). PSA at the time of PSMA-PET was significantly associated with PSMA-PET positivity (p=0.01), while initial Gleason grade group, initial treatment, injected dose, uptake time, and receipt of ADT at time to PET were not associated with PET positivity. Ultimately, PSMA-PET altered clinical management in 14 patients (67%).


PSMA-PET identified lesions in patients with non-acinar prostate cancer and remains a useful clinical tool in these challenging cases. Lower PSA levels appeared to impact detection by PSMA-PET and should be considered in the context of PSMA-PET interpretation.