Prostate Cancer Lesions Accurately Detected by New Imaging Agent

Prostate Cancer Lesions Accurately Detected by New Imaging Agent

Thomas Jefferson University researchers recently tested a new imaging technique to detect prostate cancer cells and malignant lesions — a technique they also developed — and report that it is both highly accurate and more effective than current detection methods. Their article, “VPAC1 Targeted 64Cu-TP3805 Positron Emission Tomography Imaging of Prostate Cancer: Preliminary Evaluation in Man,” was published in Urology.

Current tests to detect and stage prostate cancer rely on a biopsy, an invasive procedure that can be risky, costly and  inaccurate, allowing as many as 66 percent of cancers to go undetected. Prostate cancer can be tricky to determine since its tumor cells do not grow into a substantial mass, but spread like seeds. In standard biopsies, 12 tissue samples are generally taken and analyzed in the hope that at least one sample from a cancerous prostate will include cancer cells.

Researchers evaluated their technique, which combines a novel imaging agent with a PET imaging procedure, and has already been tested successfully for human breast cancer. The team, led by Dr. Mathew Thakur, developed the agent, called 64Cu-TP3805, to attach itself to VPAC1 receptors present on the surface of cancer cells to promote their growth. The TP3805 part of the agent hooks the receptors, and the Cu-64 — a radiation-emitting copper peptide — allows their detection by the PET (positron emission tomography) CT scan procedure, essentially revealing cancerous cells. Another advantage of this agent is its short half-life, meaning that it decays quickly, so that a person’s body radiation risk is even lower than that of a CT scan.

The researchers studied the method on 25 prostate cancer patients undergoing radical prostatectomy, or total prostate removal, who agreed to the imaging test prior to surgery. Comparing test results to the pathological exam (histology of biopsy tissues), researchers observed that the imaging procedure found 105 out of 107 cancerous lesions in the removed prostates, corresponding to a 97 percent accuracy rate. Importantly, the technique also found nine lesions that were not identified by the exam. According to the team, these results can be explained by the fact that VPAC1 receptors appear before the cell morphology changes to cancerous, and into lesions that could be identified by pathologists. Positive and negative lymph nodes, cases of benign prostatic hyperplasia, and cysts were also correctly identified using the new test.

Dr. Thakur, a professor of Radiology at Sidney Kimmel Medical College of Thomas Jefferson, and director of the Laboratories of Radiopharmaceutical Research and Molecular Imaging, said in a press release, “Results of this study exceeded our goal of detecting 80 percent of cancers seen pathologically, and provided us with real insights into how prostate cancer can be accurately imaged. A larger study that confirms these exciting findings should be conducted.”