Prostate cancer is the most common malignancy in American men, after skin cancer, and it’s the second leading cause of death from cancer in U.S. males. The disease often has no early symptoms, according the National Cancer Institute (NCI), so it’s not surprising that regularly screening men for prostate cancer became standard medical practice over the past two decades.
But the idea that most men should have yearly prostate-specific antigen (PSA) tests as a way to detect prostate cancer is changing. PSA tests measure blood levels of a protein produced by cells in the prostate gland which can be elevated in prostate cancer. But a positive PSA test doesn’t automatically mean a man has prostate cancer, and most men with an elevated PSA levels turn out not to have the disease, the NCI points out. In fact, the U.S. Preventive Task Services Task force is one of several health advisory groups that no longer recommend regular PSA screening because the benefits can outweigh the potential harms, including unneeded biopsies and over-diagnosis.
However, many men still have cancer screenings with PSA tests and higher-than-normal results often lead to worry and more invasive tests. Researchers at the Ottawa Hospital and the University of Ottawa recommend a simple way to help many men lower their stress level over an elevated PSA result and avoid one of the pitfalls of the tests — unneeded biopsies. The key is simple: Repeat the PSA test.
PSA levels can be high not because of cancer but because of other factors that fluctuate, including infections, physical activity, and even laboratory errors, Ottawa Hospital surgical oncologist and researcher Rodney Breau, MD, pointed out.
“Because of this variation, we implemented a protocol to always repeat an abnormal test before referring a patient for a biopsy,” Breau explained. “We had a hunch that this would reduce unnecessary biopsies and our study shows that our suspicion was correct."
In the first study of its kind, Breau and colleagues investigated the impact of repeating PSA tests in a broad range of men who were being screened for prostate cancer to see if the results differed.
The researchers reviewed medical records of almost 1,300 patients at the Ottawa Regional Cancer Assessment Center who had high PSA test results. They found that when PSA tests were repeated, they were normal 25 percent of the time. Only 28 percent of the men who had two different test results underwent biopsies, compared to 62 percent of men who had two elevated PSA results.
The findings showed that the second normal test was the most important test of all. When men with conflicting test results (one elevated PSA result and one that was normal) had biopsies, only three percent were diagnosed with cancer within a year. But almost 20 percent of men who had two PSA tests that were elevated went on to develop cancer in about 12 months.
"Our study has important implications for patients and the healthcare system,” said Luke Lavallée, MD, a prostate cancer surgeon and researcher at the Ottawa Hospital and the University of Ottawa. "Prostate biopsies can be uncomfortable and inconvenient for patients and, in rare cases, they can lead to infections, so we only want to do these if they are really necessary. Prostate biopsies are also expensive for the healthcare system."
"It is clear to me that any man with an abnormal PSA test should have this test repeated before a decision to biopsy," Breau added. "Some doctors and patients may be worried about missing a significant cancer diagnosis if they forgo a biopsy after conflicting test results, but our study shows this is very unlikely. It is also important to remember that the PSA test is just one factor we evaluate when deciding to do a biopsy, and these decisions are always made together with the patient, and can be revisited if risk factors change."
When an elevated PSA and further testing does result in a cancer diagnosis, the NCI points out that doesn’t mean the cancer is a high risk malignancy that needs to be treated aggressively – or at all.
Prostate cancer usually grows very slowly, and most men diagnosed with the disease who are 65 years old or older don’t die from prostate cancer. What’s more, finding and treating prostate cancer before symptoms occur doesn’t necessarily improve health or help a prostate patient live longer. So instead of undergoing immediate cancer treatment, low-risk prostate cancer patients are increasingly simply being monitored regularly to check for any disease progression.
This approach, often called watchful waiting or active surveillance, involves treating cancer only if it changes into a higher-risk form of the disease. Another study from the Ottawa Hospital and the University of Ottawa researchers found that men with slow-growing, low-risk prostate tumors are often able to safely avoid unnecessary and potentially harmful treatment with this approach.
The researchers investigated the medical records of 477 men with low-grade prostate cancer treated at the Ottawa Hospital’s Ages Cancer Assessment Clinic between 2008 and 2013. The number of men with prostate cancer who were being monitored but not treated for cancer increased dramatically from 32 percent in 2008 to 68 percent in 2013. After five years of watchful waiting, almost 60 percent of the men were still being managed with observation only because their cancers were not progressing.
“Recent data suggest that low-grade prostate cancer can grow very slowly, and therefore many patients likely don’t need treatment at all,” said Breau, who headed the study. “Some men can go for years, or maybe their entire lives, without the cancer spreading. If we monitor patients closely, we can still treat the cancer if it becomes higher risk. If the cancer doesn’t progress, they can avoid unnecessary surgery, radiation and other therapies, which can have side effects, including incontinence, impotence and bowel problems.”
June 22, 2016
Christopher Nystuen, MD, MBA