Some men with prostate cancer may have increased risks of dying from causes other than the cancer itself, a new study finds.
Researchers found that when men had their prostate cancer diagnosed after developing symptoms – and not after screening tests – they had heightened risks of dying from heart problems or other cancers.
It’s not clear what to make of the findings at this point. Mainly, they raise questions for future studies, said Dr. Anthony D’Amico, of the Dana-Farber Cancer Institute and Harvard Medical School in Boston.
“This is a study of associations, and does not prove cause-and-effect. It’s really hypothesis-generating,” said D’Amico, who was not involved in the research.
One possibility, according to the study authors, is that hormonal therapy has something to do with the increased risk of heart disease death.
D’Amico agreed that could be a factor. A number of studies, he told Reuters Health, have suggested that hormonal therapy for prostate cancer could raise the risk of heart disease death.
Prostate cancer test doesn’t cut death risk, longest study finds
The longest study yet on prostate cancer testing provides more evidence that getting screened doesn’t cut the chances of dying from the disease.
In a 20-year study of more than 9,000 Swedish men, researchers found no difference in the rate of prostate cancer deaths between the men who were periodically screened and those who weren’t.
Routine screening for prostate cancer is controversial and the new results aren’t likely to end the debate about the value of testing. Critics say screening leads to unnecessary biopsies and treatment with little proof that it saves lives. Testing is done with a physical exam and a PSA blood test.
“There is no escaping the fact that we need a better tool … to help detect prostate cancers that actually need treating, as opposed to innocent ones that do not,” said Malcolm Mason, a prostate cancer expert at Cancer Research U.K. in a statement. “In the meantime, men should be fully informed about the pros and cons of having their PSA measured.”
The standard PSA blood test looks for high levels of prostate specific antigen. The test is controversial because the PSA level can be high for many reasons. A positive result must be confirmed by a biopsy.
If prostate cancer is found, there’s no agreement on the best way to treat it: “watchful waiting,” surgery, hormone therapy, radiation, or some combination of those. Most tumors grow so slowly they are never life-threatening, and the treatments can have serious side effects.
But, D’Amico added, that link has only been seen in men with a history of heart disease going into the therapy.
SCREENING VS. USUAL CARE
The findings, reported in the British Journal of Urology International, are based on a subgroup of men who took part in a European clinical trial on prostate cancer screening.
{pagebreak}
The men, who were ages 55 to 74, were randomly assigned to either undergo periodic prostate cancer screening or be part of a control group that stuck with “usual” health care.
Exercise Cuts Prostate Cancer Death Risk
3 Hours of Vigorous Activity a Week Associated With a 61% Lower Risk of Prostate Cancer-Specific Death, Researchers Say
Men diagnosed with prostate cancer may be able to reduce their risk of death not just from prostate cancer but from any cause by exercising vigorously for at least three hours per week, new research indicates.
A study performed by researchers at the Harvard School of Public Health and the University of California-San Francisco examined the records of 2,705 men who had been diagnosed with nonmetastatic prostate cancer over an 18-year period in a project known as the Health Professionals Follow-Up Study. The men in the study reported the time they spent exercising on a weekly basis. This included running, bicycling, walking, swimming, other sports, and even outdoor work.
The researchers followed death rates among 372 men who were diagnosed with prostate cancer through screening, comparing them with 1,488 men who’d been screened but found cancer-free.
They also followed 221 men in the usual-care group who’d been diagnosed with prostate cancer after developing symptoms. Those men were compared with 884 men from the control group who had not been diagnosed with the cancer.
Looking at that latter group, the researchers found that men with prostate cancer were more likely to die from cardiovascular disease or other types of cancer over the next six years.
Just under 12 percent died of cancers other than prostate tumors, versus 7 percent of men who had not been diagnosed with prostate cancer. And 5 percent died of heart disease or stroke, compared with just over 3 percent of other men.
In contrast, men who’d had their prostate cancer caught through screening showed no increased risk of death compared with men free of prostate cancer.
OFTEN SLOW-GROWING
Prostate cancer screening, such as with PSA blood tests, often catches very early tumors that may or may not be life-threatening. Prostate cancer is often slow-growing, and may never progress to the point of being lethal.
But when men are diagnosed because they’ve developed symptoms (like problems passing urine and low back pain), the cancer is often at a more-advanced stage.
{pagebreak}
For those men, one treatment option is hormonal therapy to lower a man’s levels of testosterone, which can fuel prostate tumors’ growth.
Several studies have linked the therapy to higher-than-normal risks of cardiovascular “events,” like blood clots or heart attacks, or death from heart complications.
In this study, 27 percent of men diagnosed with prostate cancer based on symptoms ended up having hormonal therapy, according to the researchers, led by Dr. Pim J. van Leeuwen of Erasmus Medical Center in Rotterdam.
Men who walked more than 90 minutes per week at a normal to brisk pace had a 46% lower risk of dying from any cause compared to men who walked less than 90 minutes per week.
Men who reported vigorous activity for at least three hours per week had a 61% lower risk of a prostate cancer-specific death, compared with men who exercised for less than an hour per week.
“Our results suggest that men can reduce their risk of prostate cancer progression after a diagnosis of prostate cancer by adding physical activity to their daily routine,” study author Stacey Kenfield of Harvard says in a news release. “This is good news for men living with prostate cancer who wonder what lifestyle practices to follow to improve cancer survival.”
So, they say, hormonal therapy might help explain the increased risk rate of death from cardiovascular problems.
D’Amico agreed that that’s a possibility, and called it the most “interesting” point from the findings.
As for the increased rate of death from other cancers, D’Amico speculated that men with more-aggressive prostate cancer may be genetically vulnerable to other cancers as well.
Or, he added, being part of a medical study may have meant they were more likely to have screening tests for other cancers.
For now, the reasons for the findings are unclear. “This is not something that would change clinical practice,” D’Amico said.
Like with any treatment for prostate cancer, experts say the risks of hormone therapy have to be weighed against the potential benefits. For men with “high-risk” cancer that is likely to progress, for example, studies have shown that a combination of hormonal therapy and radiation can boost survival.
Men with early prostate cancer diagnosed through screening would not be the ones given hormone therapy, D’Amico said.
For those men, surgery may be an option – and so may “active surveillance.” That means putting off treatment altogether and monitoring the cancer over time.
{pagebreak}
According to the National Cancer Institute, about half of the more than 190,000 U.S. men diagnosed with prostate cancer in 2009 fell into the “low-risk” category – meaning their cancer had low odds of progressing.
Some Exercise Better Than No Exercise
She says the researchers “observed benefits at very attainable levels of activity” and that the study suggests that men with prostate cancer “should do some physical activity for their overall health, even if it is a small amount, such as 15 minutes of activity per day of walking, jogging, biking, or gardening.”
She says, however, that “doing vigorous activity for three or more hours per week may be especially beneficial for prostate cancer, as well as overall health.”
The results are significant because prostate cancer is the most frequently diagnosed cancer in men in the United States. Although more than 80% of prostate cancer patients are diagnosed with localized disease, the relative 10-year survival rate is 93% for all stages combined.
More than 2 million men in the U.S. are prostate cancer survivors.
“We observed a significant risk reduction for prostate cancer mortality with increasing vigorous activity,” the authors write.
###
SOURCE: BJU International, online January 30, 2012.
###
Increased non-prostate cancer death risk in clinically diagnosed prostate cancer
Pim J. van Leeuwen,
Suzie J. Otto,
Ries Kranse,
Monique J. Roobol,
Meelan Bul,
Xiaoye Zhu,
Harry de Koning,
Fritz H. Schro”der
Article first published online: 30 JAN 2012
DOI: 10.1111/j.1464-410X.2011.10811.x
###
What’s known on the subject? and What does the study add?
Treatment of advanced PC might put patients at an increased risk of cardiovascular events. Recent studies have suggested that the excess mortality is lower among men who were diagnosed with screen detected PC in comparison to men with clinically diagnosed PC, possibly due to the use of medications for cardiovascular disease and the change to a healthier lifestyle of men with a screen detected PC.
Men with clinically diagnosed PC have an increased risk of death unrelated to PC itself, i.e., the excess mortality is based on an increased risk of dying from other neoplasm and diseases of the circulatory or respiratory system.
