Former US President Joe Biden was diagnosed with aggressive prostate cancer earlier this month. Photo: CHRIS KLEPONIS / AFP
Explainer - Former US President Joe Biden's recent prostate cancer diagnosis has once again put a spotlight on the disease, one of the highest causes of cancer death for New Zealand men.
Biden's cancer was found to have become metastatic, or spread, elsewhere in his body. That has raised questions about how he was diagnosed and how prostate cancer screening works in general.
One in eight Kiwi men will develop prostate cancer in their lifetime, the Prostate Cancer Foundation of New Zealand says.
"In New Zealand what that translates to is around 4000 diagnoses a year and unfortunately over 730 men die of the disease," foundation CEO Peter Dickens told RNZ's Nights in an interview recently.
The prostate is a small gland beneath the bladder which produces some of the fluid that makes up semen. In grown men it's about the size of a walnut, and it's normal for it to grow larger as men age.
Māori men are 72 percent more likely to die of prostate cancer once they are diagnosed than non-Māori, while 61 percent of men overall have no symptoms when diagnosed, the foundation says.
How did metastatic cancer in a US president go undiagnosed for so long?
Biden only left office in January, and earlier this month was diagnosed with the aggressive form of prostate cancer that had spread to the bone.
Biden's cancer received a Gleason score of nine, indicating it is well advanced. Prostate cancer is given a Gleason score from six to 10; the higher the score, the more likely the cancer cells are to spread.
Biden had not been screened for prostate cancer since 2014, a spokesperson said.
There has been criticism and conspiracy theories over the news in American media.
Dr Simon van Rij is a urologist and surgeon based in Auckland. He noted diagnoses such as Biden's are "not uncommon, as prostate cancer often doesn't cause any symptoms until very late and spread outside of the prostate".
Biden is 82, and many men with age do develop some kind of prostate cancer, van Rij said.
"It is also important to acknowledge that he is over the age of 80 and prostate cancer is common in men as they get older - and many men may have prostate cancer, never know about it and die from other causes, so there is also a real danger of overdiagnosing and overtreating men for a condition that may never affect them, but the potential side effects of treatment could."
What should men look out for?
Peter Dickens, CEO of Prostate Cancer Foundation of New Zealand. Photo: Supplied
Prostate cancer can be diagnosed without any symptoms, but there are obvious things to look out for.
"As ex-President Biden said in his piece, what alerted him was problems with his waterworks, problems with urination, and that's certainly one of the main ways that people realise that something of concern is going on down there," Dickens told Nights.
"Urgency, more frequency of urination, blood in semen or urine is something that's a major warning sign and something that should take you to the doctor."
Early diagnosis is key.
"You get the best outcomes if you detect it before you perceive any symptoms of prostate cancer. Once you start experiencing symptoms of prostate cancer, in most cases your options in terms of treatments are far reduced."
So when should men get screened?
It depends. A family history of prostate cancer is important for men to be aware of.
"In New Zealand the guidance is that men should chat with their GPs about getting tested for prostate cancer using a simple blood test from the age of 50 onwards," Dickens said.
"However, if you have a family history of prostate cancer, say if your father was diagnosed... then you're two to three times more likely to be diagnosed yourself and you should start having those conversations with your GP from about the age of 40."
But as you get older, routine screening is actually considered less important if you have no symptoms or family history.
American guidelines from the Centers for Disease Control and Prevention state that "men over age 70 shouldn't be screened for prostate cancer routinely".
"In New Zealand it's slightly different," Dickens said. "Seventy, as they say, is the new 60.
"There are many 70-year-olds that are still running marathons and working and running businesses and can expect a life expectancy quite reasonably into their 90s.
"So in New Zealand you should continue testing up to the point that you have a life expectancy of about 10 years, so there's no actual set date."
A simple PSA blood test helps to diagnose prostate cancer. Photo: 123RF
How do they diagnose prostate cancer, anyway?
The primary check for prostate cancer remains the PSA test, a simple blood test which measures the amount of a prostate-specific antigen in the blood. An elevated amount of PSA may indicate signs of prostate cancer. However, it can also indicate many other non-cancerous conditions such as benign prostate hyperplasia, or BPH.
There have been concerns in recent years about overdiagnosis of PSA results, which means the test is considered along with a broader health picture.
A prostate biopsy can firmly diagnose cancer, but the invasive test - a small sample of tissue is removed and examined under a microscope - can cause painful complications, particularly in older men.
"False-positive results can lead some men to get prostate biopsies (with small risks of pain, infection, and bleeding) when they don't have cancer," the American Cancer Society says.
"PSA is still a good indicator test for risk of prostate cancer. It does not diagnose cancer, but rather shows who is more at risk and who should be investigated further," van Rij said.
"There is no level of PSA that says someone does or doesn't have prostate cancer. The levels that we use to say if it is abnormal are basically lines in the sand we draw to work out who we should investigate further from a probability perspective."
Treatment and diagnosis has also improved, he said.
"The modern pathway of diagnosis of prostate cancer now uses an MRI scan if the PSA is elevated rather than having to go straight to more invasive tests such as a needle biopsy."
In Biden's case, if he hadn't been given a PSA screening in more than 10 years, that could explain why the cancer was detected in an advanced state.
"Unfortunately because prostate cancer generally causes no symptoms until it has advanced significantly it can present with advanced disease that has spread to the bone, this is generally in people who have not had a PSA blood test before," van Rij said.
Another method of diagnosis is digital rectal examination - in other words the finger probe, which doctors can use to detect obvious growth or abnormality.
While there is a certain amount of squeamishness for some men with that test, it can still be important.
"The finger test is a very valuable test and it can detect anomalies, and I would encourage all men to take part in that as part of their annual health checks," Dickens said.
First Lady Jill Biden kisses her husband US President Joe Biden after he delivered his farewell address to the nation from the Oval Office of the White House in Washington, DC, on 15 January 2025. Photo: MANDEL NGAN / AFP
Don't we have a national prostate cancer screening programme?
While New Zealand does have a free breast cancer screening programme, there's no similar funded test for prostate cancer.
Dickens said he felt it's time Aotearoa looked closer at testing.
"We're at the stage where we should be piloting it."
New Zealand also has an invitation to join a European pilot screening project. The Prostate Cancer Foundation expressed disappointment in the lack of funding for it in the Budget announcement last week.
"We really think that it's something that needs addressing right now," Dickens said.
However, "currently no country in the world has a national prostate cancer screening programme", van Rij said.
"Scientific research has shown a small cancer specific mortality benefit from screening but at the expense of overtreatment, which is the problem for all screening programmes - including breast cancer."
"However with better diagnosis, pathways using MRI scans and avoiding overtreatment in men with low risk cancer has made a screening program more feasible."
Van Rij said there should also be an increased focus on screening in underserved communities.
"We should acknowledge the inequality of health in NZ between Māori and non-Māori, and we do know that Māori men present later with prostate cancer and have a higher chance of dying from the disease," van Rij said, "so efforts to increase detection in our Māori population are important.
"What is also currently recommended is targeting at-risk populations for screening including those with a family history of prostate cancer, certain genetic traits including BRCA 1 and 2, Māori and Pacific Islander, Afro-Caribbean."
Dickens said Biden's diagnosis, while difficult news for him and his family, does help raise broader awareness.
"It's a little tragic that someone high-profile needs to be diagnosed with something like prostate cancer to bring attention to the issue, but that's the way it is."
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