‘Invisible’ cells key to new prostate cancer treatment
A pioneering Australian study could help the men most at risk of their cancer spreading and make existing therapies more effective.
Fact file
Prostate cancer is the most commonly diagnosed cancer in Australia.
About 25,000 men are likely to be diagnosed this year.
Australia has one of the world’s highest rates of prostate cancer.
It puts more men in hospitals than any other type of cancer.
It kills more than 3,500 men a year, about 10 every day.
The rate of men dying from prostate cancer has been gradually falling over the past 20 years, but the number of aggressive prostate cancers is increasing dramatically as the population ages.
Prostate cancer metastasis occurs when cells proliferate and spread beyond the prostate to other parts of the body, often to the bone.
Over the past 40 years, five-year relative prostate cancer survival rates have increased from around 61% to 95%.
Did you know that some cancer cells can “disappear”? They trick the body’s immune system into not detecting them and then proceed to spread where they like.
That’s what happens for men who have one of the most deadly types of prostate cancer – and it’s been a huge barrier to treating the disease and extending their lives.
Now, one of Australia’s most promising prostate cancer researchers believes she’s on the cusp of what could be a “holy grail discovery” in stopping metastatic prostate cancer switching off the body's natural immune response as tumours spread to the bone.
Research by the Peter MacCallum Cancer Centre’s Dr Katie Owen could help identify men most at risk of their cancer spreading and make existing therapies more effective.
Dr Owen has identified an immune signalling pathway, which is suppressed when cancer cells move from the prostate to bone, making the tumour cells invisible.
That allows them to evade the body’s natural immune system, enabling the tumour to grow undetected and making the cancer cells resistant to therapy.
“We’ve found that in certain circumstances we can switch off these cancer cells and stop them expressing proteins which shuts down the good immune responses, creating a pro-tumour environment,” Dr Owen said.
“This discovery is really exciting because if we can make these ['invisible' cells] seen, then we can explore ways to block [them].”
The Prostate Cancer Foundation of Australia, which funded the research, said Dr Owen’s findings could transform the treatment of advanced prostate cancer.
Chief Executive Anne Savage said, “The spread of prostate cancer cells to bone is hard to predict, hard to treat, and hard to beat. This research could help identify men who are most at risk and allow us to deliver targeted therapies to slow down or stop the disease and improve overall survival.”
Dr Owen added, “Prostate cancer is different to other cancers. It’s unique in the way it metastasises because it almost always goes to the bone, which makes it even more challenging to treat effectively.
“With many of the most deadly forms of prostate cancer, the cancer cells trigger a protein which makes them invisible to the immune system, turning off the immune response that would ordinarily stop the cancer growth. This is where it gets tricky for the body, because the body can’t fight what it can’t see,” Ms Savage said.
More information about Prostate Cancer, diagnosis and treatment is available at the Prostate Cancer Foundation of Australia.
Further reading: PCFA, The Australian
