Prostate Cancer Diagnosis

Prostate Cancer Diagnosis

Prostate cancer is a very common condition; it was the most commonly diagnosed cancer in Australia in 2018.¹

In 2022, it is estimated that a male has a 1 in 6 (or 17%) risk of being diagnosed with prostate cancer by the age of 85.¹

The incidence rate for prostate cancer is expected to increase with age, highest for those aged 75–79 years.¹

In 2018, there were 21,853 new cases of prostate cancer diagnosed in Australia.¹ In 2020, there were 3,568 deaths from prostate cancer in Australia.¹

Just about everyone knows someone with prostate cancer. It may be a father, a brother, an uncle, or a very good friend. It represents a significant burden of disease with enormous social impact on our society.

Prostate cancer is something that I'm passionate about. I've dedicated much of my professional life to the diagnosis and management of prostate cancer.

Prostate cancer is a very heterogeneous disease, meaning it can present differently in individuals. Sometimes it can be very active or aggressive. Other times, it can be very slow-growing and not cause a problem during a patient's lifetime. It is important for patients to be assessed on a case-by-case basis.

In my practice, I spend a significant amount of time with patients discussing all the treatment options, the pros and cons of each treatment, potential side effects, and what those side effects mean for the patient. Together, usually over a number of consultations, we decide what is best for that particular patient.

Prostate cancer is a critical issue in our community, and fortunately, we now have excellent treatment options available for it.

PSMA PET/CT Scanning

Prostate-specific membrane antigen (PSMA) PET/CT is a newer imaging test with a growing role in the diagnosis of prostate cancer. PSMA is a protein found in high levels on the surface of most prostate cancer cells. The scan uses a small amount of a radioactive tracer that attaches to PSMA, combined with a CT scan, so that areas of possible prostate cancer can be highlighted and accurately located.

PSMA PET/CT was first used to look for prostate cancer that had spread beyond the prostate (staging) or returned after treatment. More recently, it has been studied as part of the initial diagnosis of prostate cancer, alongside multiparametric MRI (mpMRI).

The PRIMARY trial

Dr Raji Kooner was an investigator and co-author of the PRIMARY trial, a prospective multicentre Australian study led by Professor Louise Emmett (St Vincent's Hospital, Sydney) and published in European Urology in 2021.² The trial enrolled 291 men with suspected prostate cancer, who each underwent mpMRI, a pelvic PSMA PET/CT scan and a transperineal biopsy.

The trial found that adding PSMA PET/CT to mpMRI improved the detection of clinically significant prostate cancer. Sensitivity improved from 83% with mpMRI alone to 97% with the combined scans, and the negative predictive value - how reliably a negative result rules out significant cancer - improved from 72% to 91%.² In other words, combining the two scans substantially reduced false negative results. Around 19% of the men in the trial were negative on both scans, and the study suggested that in future some of these men may be able to safely avoid a biopsy.²

The combination was not without trade-offs: specificity was lower with the combined scans (40% versus 53%), meaning some men without significant cancer will have a positive scan result.² Further randomised studies are under way to confirm whether a biopsy can safely be omitted in men whose combined imaging is negative.

What does this mean for patients?

PSMA PET/CT does not replace a biopsy - a tissue sample is still required to confirm a diagnosis of prostate cancer. It is also not the appropriate investigation for every person being assessed for prostate cancer. Whether a PSMA PET/CT scan would add useful information depends on individual factors, including PSA results, MRI findings and clinical examination, and is something Dr Kooner will discuss with you at consultation.