PSMA PET imaging in the diagnosis and management of prostate cancer

Abstract

Prostate cancer is the second leading cause of cancer-related deaths in men in the United States. Imaging techniques such as CT, MRI, and bone scans have traditionally been used for diagnosis and staging. Molecular imaging modalities targeting the prostate-specific membrane antigen (PSMA) have recently gained attention due to their high affinity and accuracy. PSMA PET has been combined with other modalities such as multiparametric MRI for better diagnostic and prognostic performance. PSMA imaging has been studied at different clinical settings with a wide range of disease aggressiveness. In this review we will explore the role of PSMA PET in high-risk prostate cancer staging, biochemical recurrence, and castration-resistant prostate cancer. The primary focus of this review article is to examine the latest developments in the use of PSMA imaging and emphasize the clinical situations where its effectiveness has been demonstrated to significantly impact the treatment of prostate cancer. In addition, we will touch upon the potential future advancements of PSMA PET imaging and its evolving significance in the management of prostate cancer.

Keywords: Biochemical recurrence; PET; PSMA; Prostate cancer.

Fig. 1

a–d Example of normal 68Ga-PSMA-11 PET biodistribution in whole-body maximum intensity projection (a SUV scaled at 0–10) with cervical (b), celiac (c) and presacral (d) ganglion uptake

Fig. 2

74-year-old with high-risk prostate cancer. Pre-surgical planning 68Ga-PSMA-11 PET/CT performed. Single PSMA avid 2 mm right internal iliac chain lymph node (white arrow in panels a and d; SUVmax 4.5), not well seen on CT (white arrow on panel c). Maximum intensity projection PET a is scaled at 0–5 SUV

Fig. 3

a–b Example of local recurrence in a 75-year-old patient presenting with slowly rising PSA after prostatectomy 20 years prior. F18-DCFPyL PET/CT shows focal uptake in the right surgical bed at the anastomosis (white arrows in panels a and b)

Fig. 4

a–c Example of single PSMA lymph node disease in a 54-year-old with recent resection for prostate cancer with persistently elevated PSA. F18-DCFPyL PET/CT showed a single focus of PSMA uptake in right pelvis (panel a and b, SUVmax 4.4) corresponding to a 4 mm right pelvic side wall lymph node (panel c). Original preprostatectomy pathology showed up to Gleason 4+5 prostate adenocarcinoma in left prostate lobe and 10/17 cores were positive for cancer. Uptake in the left pelvis corresponds to ureteric activity. Maximum intensity projection view a SUV scaled at 0–5

Fig. 5

a–e 73-year-old with castration-resistant metastatic prostate cancer initially treated with RT and ADT in 2004, bone metastasis in 2019, treated with chemotherapy and RT to multiple lesions, started on 177Lu-PSMA treatment given recurrent disease and rise in PSA after baseline 18F-DCFPyL PET/CT (a). Subsequent post therapy whole-body uptake images (b–e) demonstrate gradual decrease in conspicuity of the osseous lesions, corresponding to interval treatment of the bone metastases. Overall decline in PSA levels was also noted during treatment (f). Maximum intensity projection 18F-DCFPyL PET a is scaled at 0–10 SUV

Fig. 6

a-c 74-year-old man with a PSA 8.1, Gleason 4+3 prostate cancer. Staging Ga68-PSMA-11 PET findings consistent with T3bN1bMx disease and spiculated 2.6 cm right upper lobe nodule with low radiotracer uptake (SUVmax 5.8) on a background of emphysema (white arrow in panels a–c). Subsequent FNA was consistent with SCC of lung. There is increased uptake within the prostate with known cancer and metastatic pelvic lymph nodes. Several foci of low-level radiotracer uptake without CT correlate in the posterior left sixth rib without a CT or subsequent FDG correlate, favored to be benign. Maximum intensity projection a SUV scale 0–5

Fig. 7

a, b 68Ga-PSMA-11 PET uptake due to fracture, better depicted on corresponding CT (c). Both a and b are scaled to 0–5 SUV.

Fig. 8

a–c Example of oligometastatic osseous disease in a 68-year-old man with history prostatectomy now presenting with biochemical recurrence and PSA of 1.3 ng/mL. 68 Ga-PSMA-11 PET/CT showed a single focus of PSMA uptake (white arrow in panels a and b, SUVmax 4) corresponding to a small sclerotic focus in the T8 vertebral body (white arrow in panel c). Activity below bladder corresponds to urinary contamination. Maximum intensity projection a SUV scaled at 0–5