Saturday, August 25, 2012
The head of one of the UK's leading cancer research organisations has hailed a golden age in prostate cancer drug discovery as for the fourth time in two years results are published finding a new drug can significantly extend life.
A study in the New England Journal of Medicine August 15 shows the drug enzalutamide can significantly extend life and improve quality of life in men with advanced prostate cancer -- in findings that could further widen the treatment options for men with the disease.
The Institute of Cancer Research, London, and its partner hospital The Royal Marsden NHS Foundation Trust jointly led the new Phase III trial of enzalutamide and the Phase III trials of two other drugs, cabazitaxel and abiraterone. Abiraterone was also discovered at The Institute of Cancer Research and was recently made available on the NHS. A further drug sipuleucel-T has also been shown to extend life in the two-year period.
Professor Alan Ashworth, chief executive of The Institute of Cancer Research (ICR), said cancer research in the UK was finally delivering new treatment options for men with advanced prostate cancer after a long period where the options were limited.
Professor Ashworth said: "Advanced prostate cancer is extremely difficult to treat, and it's taken a massive coordinated effort to finally bring new drugs into the pipeline, after decades where there were no options once old-style hormone treatment stopped working.
"What we're seeing now is an unprecedented period of success for prostate cancer research, with four new drugs shown to extend life in major clinical trials in just two years, and several others showing promise. It truly is a golden age for prostate cancer drug discovery and development."
Professor Martin Gore, medical director of The Royal Marsden Hospital, said: "We are delighted with the recent progress that has been made in the treatment of advanced prostate cancer and to see the impact this is having on our patients, many of whom are living longer with a better quality of life as the result of these new drugs."
Enzalutamide, a new type of hormone treatment, was assessed in 1,199 patients with metastatic castration-resistant prostate cancer that had previously received chemotherapy, in a multinational, randomised placebo-controlled trial sponsored by pharmaceutical companies Medivation and Astellas.
Median survival with enzalutamide was 18.4 months, compared with 13.6 months for men receiving a placebo. Around 43 per cent of men taking enzalutamide as part of the AFFIRM trial reported an improved quality of life, compared with 18 per cent of men taking a placebo. In November last year, the trial's Independent Data Monitoring Committee recommended that the trial be stopped early and men who received the placebo be offered enzalutamide.
Thursday, August 23, 2012
Prostate Cancer: Six Things Men Should Know About Tomatoes, Fish Oil, Vitamin Supplements, Testosterone, PSA Tests
When it comes to prostate cancer, there's a lot of confusion about how to prevent it, find it early and the best way -- or even whether -- to treat it. Below are six common prostate cancer myths along with research-based information from scientists at Fred Hutchinson Cancer Research Center to help men separate fact from fiction.
Myth 1 -- Eating tomato-based products such as ketchup and red pasta sauce prevents prostate cancer. "The vast majority of studies show no association," said Alan Kristal, Dr.Ph., associate director of the Hutchinson Center's Cancer Prevention Program and a national expert in prostate cancer prevention. Kristal and colleagues last year published results of the largest study to date that aimed to determine whether foods that contain lycopene -- the nutrient that puts the red in tomatoes -- actually protect against prostate cancer.
After examining blood levels of lycopene in nearly 3,500 men nationwide they found no association. "Scientists and the public should understand that early studies supporting an association of dietary lycopene with reduced prostate cancer risk have not been replicated in studies using serum biomarkers of lycopene intake," the authors reported in Cancer Epidemiology, Biomarkers & Prevention. "Recommendations of professional societies to the public should be modified to reflect the likelihood that increasing lycopene intake will not affect prostate cancer risk."
Myth 2 -- High testosterone levels increase the risk of prostate cancer. "This is a lovely hypothesis based on a very simplistic understanding of testosterone metabolism and its effect on prostate cancer. It is simply wrong," Kristal said. Unlike estrogen and breast cancer, where there is a very strong relationship, testosterone levels have no association with prostate cancer risk, he said. A study published in 2008 in the Journal of the National Cancer Institute, which combined data from 18 large studies, found no association between blood testosterone concentration and prostate cancer risk, and more recent studies have confirmed this conclusion.
Myth 3 -- Fish oil (omega-3 fatty acids) decrease prostate cancer risk. "This sounds reasonable, based on an association of inflammation with prostate cancer and the anti-inflammatory effects of omega-3 fatty acids," Kristal said. However, two large, well-designed studies -- including one led by Kristal that was published last year in the American Journal of Epidemiology -- have shown that high blood levels of omega-3 fatty acids increase the odds of developing high-risk prostate cancer.
Analyzing data from a nationwide study of nearly 3,500 men, they found that those with the highest blood percentages of docosahexaenoic acid, or DHA, an inflammation-lowering omega-3 fatty acid commonly found in fatty fish, have two-and-a-half times the risk of developing aggressive, high-grade prostate cancer compared to men with the lowest DHA levels. "This very sobering finding suggests that our understanding of the effects of omega-3 fatty acids is incomplete," Kristal said.
Myth 4 -- Dietary supplements can prevent prostate cancer. Several large, randomized trials that have looked at the impact of dietary supplements on the risk of various cancers, including prostate, have shown either no effect or, much more troubling, they have shown significantly increased risk. "The more we look at the effects of taking supplements, the more hazardous they appear when it comes to cancer risk," Kristal said. For example, the Selenium and Vitamin E Cancer Prevention Trial (SELECT), the largest prostate cancer prevention study to date, was stopped early because it found neither selenium nor vitamin E supplements alone or combined reduced the risk of prostate cancer. A SELECT follow-up study published last year in JAMA found that vitamin E actually increased the risk of prostate cancer among healthy men. The Hutchinson Center oversaw statistical analysis for the study, which involved nearly 35,000 men in the U.S., Canada and Puerto Rico.
Myth 5 -- We don't know which prostate cancers detected by PSA (prostate-specific antigen) screening need to be treated and which ones can be left alone. "Actually, we have a very good sense of which cancers have a very low risk of progression and which ones are highly likely to spread if left untreated," said biostatistician Ruth Etzioni, Ph.D., a member of the Hutchinson Center's Public Health Sciences Division.
In addition to blood levels of PSA, indicators of aggressive disease include tumor volume (the number of biopsy samples that contain cancer) and Gleason score (predicting the aggressiveness of cancer by how the biopsy samples look under a microscope). Gleason scores range from 2-5 (low risk) and 6-7 (medium risk) to 8-10 (high risk).
"Men with a low PSA level, a biopsy Gleason score of 6 or lower and very few biopsy samples with cancer are generally considered to be very low risk," Etzioni said. Such newly diagnosed men increasingly are being offered active surveillance -- a watchful waiting approach -- rather than therapy for their disease, particularly if they are older or have a short life expectancy.
"The chance that these men will die of their disease if they are not treated is very low, around 3 percent," she said. Similarly, such men who opt for treatment have a mortality rate of about 2 percent. "For the majority of newly diagnosed cases of prostate cancer, giving initial clinical and biopsy information, we can get a very good idea of who should be treated and who is likely to benefit from deferring treatment."
Myth 6 -- Only one in 50 men diagnosed with PSA screening benefits from treatment. "This number, which was released as a preliminary result from the European Randomized Study of Prostate Cancer Screening, is simply incorrect," Etzioni said. "It suggests a very unfavorable harm-benefit ratio for PSA screening. It implies that for every man whose life is saved by PSA screening, almost 50 are overdiagnosed and overtreated."
"Overdiagnosis" is diagnosing a disease that will never cause symptoms or death in the patient's lifetime. "Overtreatment" is treating a disease that will never progress to become symptomatic or life-threatening.
The 50-to-one ratio is based on short-term follow-up and "grossly underestimates" the lives likely to be saved by screening over the long term and overestimates the number who are overdiagnosed. "The correct ratio of men diagnosed with PSA testing who are overdiagnosed and overtreated versus men whose lives are saved by treatment long term is more likely to be 10 to one," she said.
Friday, August 10, 2012
Although they're standard treatment for men with prostate cancer who are taking hormonal therapy, calcium and vitamin D supplements may do more harm than good, according to a new study.
Men who undergo hormone-depletion therapy for prostate cancer are at risk for osteoporosis, but the supplements do not prevent this bone loss and may actually boost patients' odds for heart disease and aggressive prostate cancer, research from Wake Forest Baptist Medical Center suggests.
"Calcium and/or vitamin D supplementation to prevent loss of bone mineral density in these men seems so logical that no one had questioned whether it works," study co-author, Mridul Datta, a postdoctoral fellow at Wake Forest Baptist, explained in a hospital news release.
"It wouldn't be so bad if there simply was no obvious benefit," added the study's lead author, Gary Schwartz, a prostate cancer epidemiologist at Wake Forest Baptist. "The problem is that there is evidence that calcium supplements increase the risk of cardiovascular disease and aggressive prostate cancer, the very disease that we are trying to treat."
In the study, the researchers reviewed guidelines for calcium and vitamin D supplements as well as the results of 12 clinical trials of these supplements involving almost 2,400 men with prostate cancer. All of the men were receiving hormone-deprivation therapy. The researchers also examined the men's bone mineral density before and after treatment.
According to the study, the men undergoing hormone therapy for prostate cancer who took the recommended daily doses of calcium and vitamin D supplements lost bone density.
The researchers also pointed out that increased dietary calcium is associated with a greater risk for aggressive prostate cancer and heart disease.
"The wake-up call of these findings," concluded Datta, "is that the presumption of benefit from calcium and vitamin D supplements that have been routinely recommended to these men must be rigorously evaluated."
The study's authors said more research is needed to confirm their findings and investigate the possible risks of calcium and vitamin D supplementation, particularly heart disease and prostate cancer.
One expert agreed that more study is needed.
The study authors "say that traditional approaches use too little calcium and/or vitamin D, but that as one increases the doses there are other risks, such as cardiovascular events," noted Dr. Louis Potters, a prostate cancer specialist and chair of radiation medicine at North Shore - LIJ Health System, in New Hyde Park, N.Y. "So that the trade-off for treating osteoporosis is associated with other risks."
Potters stressed that "not all men with prostate cancer need hormone therapy, only those with high-risk or advanced disease. And for those men, they need to have a discussion with their physician about the risks of these medications and how best to perhaps mitigate some of those risks."
The study was published online in the July issue of The Oncologist.