A new approach may help to improve the accuracy of tests for the number one cancer in men.
Prostate cancer holds an unenviable title: it is the most common cancer in men in the UK comprising just under one quarter of all newly diagnosed cancer cases in men. In 2008 around 101 men were diagnosed with cancer in the UK every day but the heartening news is that only one in 26 men die of prostate cancer; they are more likely to die with it than from it.
One difficulty that doctors and their patients face is that diagnosing this particular cancer is not an exact science. A Prostate Specific Antigen (PSA) test, to look for raised PSA levels in your blood is the most commonly used but a raised level doesn’t necessarily mean you have cancer. The majority of men who do have the disease don’t have raised PSA levels and over 65 percent of men with a raised level don’t have cancer.
There are other tests, including a digital rectal examination (DRE), where your doctor feels for changes in the surface of your prostate gland by putting a finger up your bottom. If your GP thinks you are at risk of having prostate cancer they will refer you to a hospital for further tests. The test you are most likely to have is the transrectal ultrasound-guided biopsy (TRUS). Using an ultrasound probe your doctor will take tissue samples from your prostate.
A recent study from the University of Michigan Comprehensive Cancer Center and the Michigan Center for Translational Pathology may provide cancer specialists with another, more reliable means of diagnosing prostate cancer. The new test looks for gene fusion – TMPRSS2:ERG – to give the scientific name. This fusion is believed to cause prostate cancer – studies of prostate tissue have shown its presence nearly always indicates cancer.
Because TMPRSS2:ERG only occurs in about 50 percent of prostate cancers, the scientists added PCA3, another marker, to their test. These combined elements were better at predicting cancer than either used on its own.
“Testing for TMPRSS2:ERG and PCA3 significantly improves the ability to predict whether a man has prostate cancer,” says lead author Scott Tomlins, MD, PhD, a pathology resident at the University of Michigan. “We think this is going to be a tool to help men with elevated PSA decide if they need a biopsy or if they can delay having a biopsy.”
“Many more men have elevated PSA than actually have cancer but it can be difficult to determine this without biopsy. This test will help in this regard. The hope is that this test could be an intermediate step before getting a biopsy,” explained senior study author Arul Chinnaiyan, MD, PhD, director of the Michigan Center for Translational Pathology.
The test isn’t available yet, but the University of Michigan hope to be able to offer it to their patients within the year.