WASHINGTON - The American Cancer Society says one in nine men will be diagnosed with prostate cancer in his lifetime and one in 41 will die from it. Several news studies offer hope that these number could decrease with early and accurate diagnosis.
A new study based on a randomized controlled trial on 300 prostate cancer patients in Australia has found that a molecular imaging technique is more accurate than conventional medical imaging that uses CT (computed tomography) and bone scan.
Prostate cancer is treated by surgery to remove the prostate or by intensive radiotherapy that targets the tumor. Doctors often use CT and bone scans to determine if the cancer has spread to other parts of the body.
A team led by Professor Michael Hofman conducted trials on prostate cancer patients in 10 hospitals in Australia using the prostate-specific membrane antigen PET-CT scan.
“We inject a radio-active small molecule intravenously. It finds its way to prostate cancer cells and we then image the whole body on a positron emission tomography scanner, i.e. PET (positron emission tomography) scanner and this enables us to visualize the distribution of disease spread with striking tumor-to-background contrast,” said Hofman.
The trials showed that prostate-specific membrane antigen PET-CT scan had a 27% greater accuracy than that of conventional imaging, which proved to have lower sensitivity. That means the new imaging has 92% accuracy compared to 65% of a CT bone scan. A follow-up trial conducted after six months confirmed the initial results.
The study, published in The Lancet medical journal, says that “the primary outcome was accuracy of first-line imaging for identifying either pelvic nodal or distant-metastatic disease.”
Hofman’s research team recommends the use of new scans in routine clinical practice instead of the current CT and bone scans for better accuracy. They say a more accurate imagery can help doctors determine whether to use targeted treatment or more advanced treatment for the whole body. A more accurate diagnosis cuts the need for repeated radio-active testing and thus cuts a patient’s exposure to harmful radiation. It also is likely to reduce the number of cancer relapse cases.
Hereditary Study of Prostate Cancer
Another study may help identify men who are more likely to get prostate cancer than others. Researchers at the Vanderbilt University, Nashville, Tennessee, have identified haplotypes, ancestral fragments of DNA, associated with hereditary prostate cancer. They compared genetic data of two groups of men with prostate cancer, one with a strong family history of the disease and another without a family history of prostate cancer. They analyzed the haplotypes of 2,300 men at a location of chromosome 8. The Vanderbilt team has earlier found that a gene on chromosome 8 is particularly associated with prostate cancer susceptibility.
"We've taken a comprehensive shotgun approach to investigate data at this location and have been able to deconstruct how it contributes to risk, including which of the haplotypes impact age of onset and also aggressiveness," said researcher Jeffrey R. Smith.
The study, published in Nature Communications, says roughly 9% of prostate cancer is linked to heritability. But one mutation increased risk as much as 22-fold. Another mutation increased risk 4-fold, and was observed even among men without a strong family history. The study is believed to be the first to identify haplotypes comprehensively from all associated genetic variants.
Vanderbilt researchers earlier found that a mutation in a particular gene predisposes men of European descent to prostate cancer. They found the mutation to be rare but carrying an 8% risk of prostate cancer among those who inherit it.
Finding Active Cancer
Another new study says that a test that checks for prostate cancer DNA in blood could provide the earliest evidence that prostate cancer is active.
The study by researchers at Britain’s University College London Cancer Institute says that prostate cancer leaves a detectable “fingerprint” in blood.
"This test could be the first to tell us cancer has gotten into blood before the spread is large enough to see on imaging," said Mark Emberton, dean of the faculty of medical sciences. "This could allow targeting of treatment for men at the highest risk of prostate cancer spread."
The study published earlier this month in The Journal of Clinical Investigation says the finding could help doctors monitor tumor behavior, see if it has spread and choose the best treatment. The technique is still being tested on patients to determine if it can complement or replace the current prostate-specific antigen test.
Less Aggressive vs. More Aggressive
Scientists at the University of East Anglia (UEA) say they have discovered a method to distinguish less aggressive from more aggressive forms of prostate cancer that eventually cause a patient’s death.
The findings are meant to help doctors avoid perhaps unnecessary and harmful treatment for less aggressive types of cancer. The new study shows how the number of aggressive cells in a tumor sample defines how quickly the disease will progress and spread. The study also reveals three new subtypes of prostate cancer that could be used to stratify patients for different treatments.
“Our aim is to use more sophisticated analytical approaches to de-convolute the structure of prostate cancer transcriptome data, providing novel clinically actionable information for this disease,” said the team.
Lead researcher Colin Cooper said: “Prostate cancer is the most common cancer in men in Britain. It usually develops slowly, and the majority of cancers will not require treatment in a man’s lifetime. However, doctors struggle to predict which tumors will become aggressive, making it hard to decide on treatment for many men.”
In the United States prostate cancer is the second most common type of cancer in men after skin cancer. The American Cancer Society says the chance of having prostate cancer rises rapidly after the age of 50 and that affects different races differently. It develops more often in African-American men and less often in Asian-American and Latino men. It says prostate cancer seems to run in some families and that several inherited gene changes (mutations) seem to raise prostate cancer risk.
The new studies promise to help improve and individualize treatment of prostate cancer and save lives.