Redefining Precision Diagnostics with PSMA PET Imaging for Prostate Cancer

07 Mar, 2022

Achieving superior precision in diagnostics is one of the critical factors in successful cancer management – this is because there is no right treatment without an accurate diagnosis.

Accurate diagnosis promotes timely treatment, which not only increases the chances of survival but will also help patients have an improved quality of life after the treatment. Receiving accurate diagnosis becomes especially important in slow-growing cancers like prostate cancer. Previously prostate cancers were diagnosed through biopsies, PET scans and MRI scans.

In recent times, researchers have come up with a new method, called PSMA PET imaging or prostate-specific membrane antigen positron emission tomography. This is a groundbreaking imaging technique that helps uro-oncologists detect or track tumours that are hard to find through conventional diagnostic methods. Unlike other imaging techniques, the tumour “glows” during the PSMA PET imaging, and this helps the uro-oncologist get a much clearer view of cancer and achieve a better diagnosis.

Currently, the researchers are studying the usage of PSMA PET imaging in all stages of prostate cancer management – from initial screenings and active surveillance to treatment of early-recurrent and metastatic prostate cancer.

What is PSMA PET Imaging, and How Does It Work?

PSMA PET imaging is a molecular imaging technique for high precision diagnostics and effective management of prostate cancer. It is a highly sensitive imaging method for early-stage prostate cancers too. A study conducted on the accuracy of this technique has reported that PSMA PET scans are 92% accurate in the detection of metastatic tumours when compared to other imaging techniques like CT scans and bone scans that reported 65% accuracy.

Prostate-Specific Membrane Antigen or simply PSMA is a receptor protein that is present on the surface of the prostate cells. These receptor proteins are present in high numbers on prostate cancer cells. The increased number of these receptors serves as an excellent target for staging and treatment planning of prostate cancer. PSMA PET imaging uses a special dye with radioactive tracers, which when combined are referred to as PSMA tracers.

During the imaging, these tracers that are injected into the patient’s body go and bind to the PSMA receptors present on the prostate cancer cells, and the regions where these cancer cells are present light up. This makes it easy for uro-oncologists to get detailed information on the stage of the disease and its other properties.

Applications of PSMA PET Imaging

Initial Screening and Diagnosis of Prostate Cancer

PSMA PET Imaging is proven to be an effective screening and diagnostic method for prostate cancer. PSMA PET imaging is reported to offer more accurate diagnostic results (figure A) when compared to conventional diagnostic methods like MRI scans. (figure B)

Image Courtesy: INDIANA SCHOOL OF MEDICINE, Urology Department.

Primary Treatment for Prostate Cancer

As we speak, numerous studies are being carried out on broadening the applications of PSMA PET imaging - one of them is treatment delivery. By delivering a more detailed view of cancer, PSMA PET imaging supports various prostate cancer treatments such as high-intensity focussed ultrasound (HIFU), robotic prostatectomy, etc.

In the case presented below, prostate cancer was diagnosed through PSMA PET imaging (left). It was later treated through high intensity focussed ultrasound (HIFU). Six months post-treatment, the patients PSMA PET results came back negative, and his PSA readings had dropped from 10.0 to 1.4 (right).

Image Courtesy: INDIANA SCHOOL OF MEDICINE, Urology Department.

Management of Early Recurrence of Prostate Cancer

PSMA PET imaging supports efficient follow-up care after prostate cancer treatment. This imaging method detects even smaller abnormal masses and helps in catching the recurring prostate cancers in their earlier stages. During PSMA PET imaging, the PSMA tracer attaches to the tumour, and this region lights up making the detection and diagnosis easier.

Diagnosing Metastatic Prostate Cancer

PSMA PET imaging is used to diagnose aggressive prostate cancer, too. Since the PSMA tracer binds to the prostate cancer cells wherever they are found throughout the body, this imaging technique is ideal to diagnose prostate cancers that have spread outside the prostate (figure below). It also helps uro-oncologists devise the best treatment plans for patients with metastatic prostate cancers.

In the figures below, the PSMA PET image of recurring prostate cancer (left) is compared with the 11C-acetate PET image of the same case (right). The tumours that have spread to lymph nodes are clearly visible on the PSMA PET image than on the PET image, which is on the right side.

Image Courtesy: INDIANA SCHOOL OF MEDICINE, Urology Department.

Bottom Note:

Precision diagnostics is the future of cancer care. Delivering the right treatment the first time is critical; nevertheless, accurate diagnosis is imperative for the best treatment plan. However, in recent times, the introduction of state-of-the-art technology has remarkably increased the quality of cancer diagnosis in our country by facilitating early detection and by delivering sufficient diagnostic information during all stages of cancer and helping effective treatment planning.

Other Blogs