Prostate cancer is the most common form of cancer among men, with more than 40,000 diagnoses a year in the UK, and 10,000 deaths Photo: ALAMY
12:01AM BST 11 Apr 2014
284 Comments Up to half of men diagnosed with prostate cancer are being given “false hope” by tests that are underestimating the severity of their disease, according to the authors of a new study.
The research by Cambridge University found that 50 per cent of men who were reassured that their disease was slow-growing and confined to the prostate in fact turned out to have more dangerous tumours.
In addition, in one third of cases, the biopsies used to establish the severity of disease did not even detect that it had spread beyond the prostate, the major study found.
Prostate cancer is the most common form of cancer among men, with more than 40,000 diagnoses a year in the UK, and 10,000 deaths.
When disease is found, doctors undertake biopsies to see whether it is slow-growing - and in some cases could simply be monitored - or whether it is the aggressive form requiring the most urgent treatment.
The Cambridge scientists compared the staging and grading of more than 800 patients with cancer, before and after they had surgery to remove their prostate.
They found that of 415 patients whose cancer had been classified as slow-growing and confined to the prostate, 209 were found to have a more aggressive disease than originally thought when assessed after surgery.
In almost one third of cases, the cancers which had been thought to be local had in fact spread beyond the prostate gland.
The new findings, published in the British Journal Of Cancer, call into question the ability of experts to grade and stage prostate cancers on the basis of biopsy samples.
They also cast doubt on the “active surveillance” strategy of simply monitoring men with slow-growing prostate cancer, who often receive no treatment until tests show that their condition has worsened.
Urological surgeon Greg Shaw, from the Cancer Research UK Cambridge Institute, said: “Our results show that the severity of up to half of men’s prostate cancers may be underestimated when relying on tests before they have surgery.
“This highlights the urgent need for better tests to define how aggressive a prostate cancer is from the outset, building on diagnostic tests like MRI (magnetic resonance imaging) scans, and new biopsy techniques which help to more accurately define the extent of the prostate cancer.”
“Whilst active surveillance would seem to be a safe approach for some men, nearly a third will end up needing surgery or radiotherapy within five years,” he warned.
Slow-growing prostate cancers, known as “pussycats”, are very different from the more aggressive and dangerous “tiger” variety.
In some cases, especially among older men, patients can live a normal life span before a “pussycat” cancer becomes a threat.
An aggressive “tiger” may quickly spread if it is not surgically removed or destroyed using radiotherapy or hormone treatment.
All men over the age of 50 are offered NHS screening which can indicate an inceased risk of prostate cancer,
However, there has long been debate over the value of Prostate Specific Antigen (PSA) blood marker tests, because high and low PSA readings do not necessarily indicate whether or not cancer is present.
Dr Iain Frame, Director of Research at Prostate Cancer UK said: “Accurate prostate cancer diagnosis continues to be one of the biggest challenges facing the disease today. The results of this study highlight yet again that existing tests cannot provide a precise picture of the aggressiveness of a man’s cancer, often leaving men and their doctors to make difficult decisions about treatment without all the facts.”
He said that until there were better tests, it was important that patients had an opportunity to discuss the pros and cons of every treatment option available with their doctor.
Professor Malcolm Mason, Cancer Research UK’s prostate cancer specialist, said: “At the moment the biopsy, MRI and PSA tests that we use to assess the severity of prostate cancers are the best methods we have but, as this study shows, they don’t always get it right.
“Despite the limitations that this study shows, all evidence so far points to active surveillance being safe provided men are carefully selected. But we need better methods of assigning a grade and stage so that no man has to unnecessarily undergo treatment, while at the same time making sure we detect and treat the cancers that really need it.”
They found that of 415 patients whose cancer had been classified as slow-growing and confined to the prostate, 209 were found to have a more aggressive disease than originally thought when assessed after surgery.
In almost one third of cases, the cancers which had been thought to be local had in fact spread beyond the prostate gland.
The new findings, published in the British Journal Of Cancer, call into question the ability of experts to grade and stage prostate cancers on the basis of biopsy samples.
They also cast doubt on the “active surveillance” strategy of simply monitoring men with slow-growing prostate cancer, who often receive no treatment until tests show that their condition has worsened.
Urological surgeon Greg Shaw, from the Cancer Research UK Cambridge Institute, said: “Our results show that the severity of up to half of men’s prostate cancers may be underestimated when relying on tests before they have surgery.
“This highlights the urgent need for better tests to define how aggressive a prostate cancer is from the outset, building on diagnostic tests like MRI (magnetic resonance imaging) scans, and new biopsy techniques which help to more accurately define the extent of the prostate cancer.”
“Whilst active surveillance would seem to be a safe approach for some men, nearly a third will end up needing surgery or radiotherapy within five years,” he warned.
Slow-growing prostate cancers, known as “pussycats”, are very different from the more aggressive and dangerous “tiger” variety.
In some cases, especially among older men, patients can live a normal life span before a “pussycat” cancer becomes a threat.
An aggressive “tiger” may quickly spread if it is not surgically removed or destroyed using radiotherapy or hormone treatment.
All men over the age of 50 are offered NHS screening which can indicate an inceased risk of prostate cancer,
However, there has long been debate over the value of Prostate Specific Antigen (PSA) blood marker tests, because high and low PSA readings do not necessarily indicate whether or not cancer is present.
Dr Iain Frame, Director of Research at Prostate Cancer UK said: “Accurate prostate cancer diagnosis continues to be one of the biggest challenges facing the disease today. The results of this study highlight yet again that existing tests cannot provide a precise picture of the aggressiveness of a man’s cancer, often leaving men and their doctors to make difficult decisions about treatment without all the facts.”
He said that until there were better tests, it was important that patients had an opportunity to discuss the pros and cons of every treatment option available with their doctor.
Professor Malcolm Mason, Cancer Research UK’s prostate cancer specialist, said: “At the moment the biopsy, MRI and PSA tests that we use to assess the severity of prostate cancers are the best methods we have but, as this study shows, they don’t always get it right.
“Despite the limitations that this study shows, all evidence so far points to active surveillance being safe provided men are carefully selected. But we need better methods of assigning a grade and stage so that no man has to unnecessarily undergo treatment, while at the same time making sure we detect and treat the cancers that really need it.”
