PET/CT Hybrid Imaging Technique Provides Accurate Guide for Prostate Cancer Biopsy

Prostate-specific molecular imaging at initial biopsy and preoperative planning can accurately determine and delineate the extent of prostate cancer. The imaging technique was a type of positron emission tomography (PET) and computed tomography (CT) called 68Ga-PSMA PET/CT. These results were presented at the 2016 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging.¹

Prostate cancer is the second most frequent cancer in men. Approximately 1 in 7 men will receive a diagnosis of prostate cancer within their lifetime. Surgical resection is the standard of care for prostate cancer.

PET and CT can be used together to image the physiology and structure of recurrent prostate cancer. Researchers have recently developed PET imaging that focuses on prostate-specific membrane antigen (PSMA). The surface of prostate cancer cells overexpresses PSMA.

PSMA can be detected if the disease spreads to other organs. By administering small doses of gallium-68 (68Ga), a radioactive material, and PSMA-HBED-CC before PET/CT scanning, imaging can detect PSMA with high accuracy.

Researchers administered 68Ga-PSMA PET/CT to 21 patients with biopsy-proven prostate cancer at a median of 4 days prior to radical prostatectomy. Results showed the procedure had 67% sensitivity, 92% specificity, 97% positive predictive value, 42% negative predictive value, and 72% accuracy.

“PSMA shows significant over-expression on prostatic cancer cells, and Ga-68 PSMA PET/CT demonstrates a high rate of detection in patients with recurrent, metastatic prostate cancer. However much less research has been conducted for the accuracy of PSMA imaging at the start of the disease,” said Wolfgang P. Fendler, MD, from the department of nuclear medicine at Ludwig-Maximilians-Universität of Munich, Munich, Germany.

“The results of our study indicate that Ga-68 PSMA PET/CT accurately identifies affected regions of the prostate and might thus present a promising tool for noninvasive tumor characterization and biopsy guidance.”

68Ga-PSMA PET/CT correctly detected invasion of seminal vesicles in 11 of 21 patients (52%) with 86% accuracy and spread through the capsule in 12 of 21 patients (57%) with 71% accuracy.

“68Ga-PSMA PET/CT accurately predicts location and extent of primary prostate cancer. Our preliminary findings warrant further investigation of 68Ga-PSMA PET/CT in conjunction with needle biopsy,” wrote the authors.

Reference

1. Fendler WP, Schmidt DF, Wenter V, et al. 68Ga-PSMA-HBED-CC PET/CT detects location and extent of primary prostate cancer. Presentation at: 2016 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging; June 11-15, 2016; San Diego, CA. Scientific paper 608.