30 October 2022
A whole-body scan can predict which patients will benefit most from a radioactive treatment for men with prostate cancer
Biomarker analysis from the TheraP clinical trial co-funded by PCFA has found whole-body PET scans before treatment for prostate cancer can predict patient outcomes.
The findings were published recently in The Lancet Oncology and presented at the 35th Annual Congress of the European Association of Nuclear Medicine in Barcelona.
PCFA Chief of Mission and Head of Research, Professor Jeff Dunn AO, said the analysis would give clinicians greater confidence in managing and treating prostate cancer.
“This is just the latest breakthrough from the TheraP study, which earlier proved the superiority of Lu-PSMA compared to cabazitaxel chemotherapy for men with metastatic castration-resistant prostate cancer.
“With this new knowledge, specialists will be able to make early decisions about treatment pathways for men with advanced and aggressive forms of prostate cancer, in the hope of improving the patient’s response to treatment and overall survival.
“So far the TheraP clinical trial has discovered the Lu-PSMA works to reduce PSA, shrinks prostate cancer tumours, slows down tumour spread, and causes fewer and less severe side-effects compared to standard of care.
“More recently, the three-year follow up study demonstrated an ongoing positive clinical response, which is magnificent news for men with metastatic castration-resistant prostate cancer, providing great hope we can keep deadly prostate cancers at bay.”
Lead investigator on the TheraP study, Professor Michael Hofman, said many thousands of Australian men with advanced prostate cancer could benefit from the new findings.
“This Australian first study shows that a new era of personalised medicine has arrived. We show that a new whole-body scan can be used to identify men with prostate cancer that are much more likely to respond to radioactive Lu-PSMA.”
The biomarker study's lead author, Dr James Buteau, said the research was significant.
“PET scans are like a small window into the future. We can peek through and get a good idea of how Lu-PSMA should work for these patients.”
TheraP was the first trial comparing Lutetium-177 PSMA-617 (Lu-PSMA), a novel radioactive treatment, to chemotherapy called cabazitaxel, for people with metastatic castration-resistant prostate cancer.
TheraP showed that patients receiving Lu-PSMA had better responses than cabazitaxel, with more patients having reduction in PSA (a blood marker of prostate cancer), tumours getting smaller on scans, and longer duration of time of tumour control.
There were also fewer and less severe side effects with Lu-PSMA. Results were published last year in The Lancet, one of the world’s most well-respected medical journals.
This new biomarker analysis investigated whether whole body PET scans performed before treatment could predict patient outcomes. 200 patients were recruited into the study at 11 hospitals around Australia and given two types of whole-body PET scans.
These scans show the location of prostate cancer in the body but also give information about how those cancer deposits behave. Patients first had a PSMA PET/CT, measuring the amount of prostate specific membrane antigen (PSMA), a receptor on the surface of cancer cells which is also the target for the Lu-PSMA treatment.
Patients then had a FDG PET/CT, which measures the amount of sugar the tumours use and where these faster-growing tumours are.
The results found that with patients with high uptake on the PSMA PET/CT could predict higher likelihood of favourable response Lu-PSMA than cabazitaxel. Study authors conclude that patients with disease like this are more likely to benefit from Lu-PSMA.
The study also found that a high volume of disease on FDG PET was associated with worse prognosis regardless of whether the patients received Lu-PSMA or cabazitaxel.
ENDS
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About Metastatic Castration-Resistant Prostate Cancer
Metastatic prostate cancer is cancer that has spread from the prostate to other parts of the body, most commonly to bones and lymph nodes. This is treated by suppressing the sex hormone testosterone which can drive tumour growth. Over time, tumours can be resistant to this hormone therapy and the disease is then called castration-resistant. This type of advanced disease is often a lethal condition and novel treatments are needed to improve outcomes.
About ANZUP
ANZUP is the leading cancer-cooperative clinical trials group that brings together all of the professional disciplines and groups involved in researching and treating urogenital cancers and conduct high quality clinical research. ANZUP identifies gaps in evidence and areas of clinical need and collaborates with the best clinicians and researchers in GU cancer. ANZUP receives valuable funding support from Prostate Cancer Foundation of Australia for research into prostate cancer, including co-funding of the ProPSMA, TheraP, and EVOLUTION clinical trials.
