prostate news

Good for the Prostate, Bad for the Brain?

July 31, 2008 -- A common treatment for men with prostate cancer may be negatively impacting their ability to think and reason clearly.

Researchers who reviewed previous studies on hormone deprivation therapy, also called androgen depletion therapy, found between 47 percent and 60 percent of men on the treatment saw a drop in at least one area of cognition. Processes that depend on spatial ability were among the most commonly affected, as were those linked to higher-order skills, such as the ability to do more than one thing at once.

How does the treatment impact the brain? The authors explain hormone deprivation therapy depletes the male hormone testosterone, which is known to feed prostate cancer tumors. But testosterone also plays a key role in modulating brain chemicals called neurotransmitters and fostering connections between neurons -- two processes vital to the ability to think and reason.

Since more and more men are being given the treatment -- including some who have not been diagnosed with prostate cancer but do have high PSA levels -- the investigators believe more needs to be done to ensure doctors are aware of the potential effects of the therapy on the brain.

They also note previous research has linked the therapy to other problems as well, ranging from hot flashes and osteoporosis to erectile dysfunction and the risk of serious diseases like diabetes and heart disease.

The study was led by researchers from Memorial Sloan-Kettering Cancer Center in New York City.

SOURCE: CANCER, published online July 28, 2008

New Treatment for Advanced Prostate Cancer

July 29, 2008 — Researchers at the University of Adelaide have developed a novel approach to treating advanced prostate cancer that could be more effective with fewer side effects.

Professor Wayne Tilley and Dr Lisa Butler of the University’s Dame Roma Mitchell Cancer Research Laboratories have discovered that by using existing prostate cancer drugs in combination with new drugs at lower doses, they can expect to generate better results for patients than current treatments.

Growth of prostate cancer is initially dependent on hormones called androgens, which traditionally have been suppressed to stop tumour growth. However, despite an initial response, resistance to hormone deprivation often occurs and the tumour starts to grow again, Professor Tilley says.

“Men undergoing hormone deprivation therapy can also experience significant side effects, including reduced libido, impotence, hot flushes, tiredness and sweating, gradual decrease in body hair, reduced bone and muscle strength and cognitive changes,” he adds.

Professor Tilley and Dr Butler have successfully killed prostate cancer cells in laboratory studies using low doses of a combination therapy of drugs including bicalutamide (an anti-androgen that opposes the action of androgen on the tumour), and the inhibitors 17AAG and vorinostat.

These new drugs block key cancer survival pathways, but are not particularly effective in killing prostate cancer cells if given alone.

“We can now confirm that a very low level of bicalutamide is capable of inhibiting cancer cell proliferation by more than 10-fold when combined with either vorinostat or 17AAG, making our current treatments much more effective and causing fewer side effects,” says Dr Lisa Butler.

All the drugs needed for combination therapy are already approved for use in clinical trials, so the new therapy can be readily tested in patients with advanced prostate cancer.

Professor Chris Sweeney, a world recognised medical oncologist and Director of Clinical Trials at the Royal Adelaide Hospital Cancer Centre, will lead a multidisciplinary team to test the new treatment.

“The ultimate test of this exciting laboratory breakthrough is to see if it improves outcomes and quality of life for men suffering from advanced prostate cancer,” he says.

“The strong partnership between medical scientists and clinicians at the University of Adelaide and the Royal Adelaide Hospital means patients can benefit from advances in medical science much faster than in the past.”

Professor Tilley is a founding member of the Freemasons Foundation Centre for Men’s Health, which is working towards establishing a national prostate cancer research facility in Adelaide.

Radiation Treatment for Cancer After Radical Prostatectomy Linked With Increased Survival

June 17, 2008 — Preliminary findings indicate that for men who underwent radical prostatectomy, radiation treatment after prostate cancer recurrence was associated with an increase in prostate cancer-related survival, according to a study in the June 18 issue of JAMA.

“Nearly 60,000 men (27 percent of newly diagnosed cases) will have undergone radical prostatectomy in 2007. Although surgery provides excellent cancer control, approximately 15 percent to 40 percent of these men will experience cancer recurrence within 5 years, usually manifested only by elevated prostate-specific antigen (PSA) level,” the authors write. For such men it is unknown whether salvage radiotherapy (radiation treatment given after recurrence of cancer) offers a survival benefit compared with observation alone.

Bruce J. Trock, Ph.D., of the Johns Hopkins University School of Medicine, Baltimore, and colleagues conducted a study to determine the association between salvage radiotherapy and prostate cancer–specific survival. The study included 635 men who underwent radical prostatectomy from 1982-2004, were followed up through December 2007, and who experienced biochemical recurrence (increased PSA levels) and/or local cancer recurrence and received either no salvage treatment (n = 397), salvage radiotherapy alone (n = 160), or salvage radiotherapy combined with hormonal therapy (n = 78).

With a median (midpoint) follow-up of 6 years after recurrence and 9 years after prostatectomy, 116 men (18 percent) died from prostate cancer, including 89 (22 percent) who received no salvage treatment, 18 (11 percent) who received salvage radiotherapy alone, and 9 (12 percent) who received salvage radiotherapy and hormonal therapy. The researchers found that salvage radiotherapy, regardless of whether given alone or with hormonal therapy, was associated with a statistically significant decrease in the risk of death of nearly 60 percent and a 3-fold increase in prostate cancer–specific survival relative to those who received no salvage treatment. Salvage radiotherapy was also associated with a significant increase in overall survival.

The increase in prostate cancer–specific survival associated with salvage radiotherapy was limited to men with PSA doubling time (a measurement of how aggressive the disease is) of less than 6 months. Among 166 men (26 percent) with PSA doubling time of less than 6 months, salvage radiotherapy alone and salvage therapy with hormonal treatment were associated with a reduction in risk of prostate cancer–specific death by more than 75 percent. Salvage radiotherapy was associated with an increase in survival only if given sooner than 2 years after recurrence.

Men whose PSA level never became undetectable after salvage radiotherapy did not experience a significant increase in prostate cancer–specific survival.

“This study provides provocative evidence that even men with adverse prognostic features such as rapid PSA doubling time or high Gleason score [a grading system for prostate cancer] may benefit from salvage radiotherapy,” the authors write.

“… our data provide the first evidence (albeit retrospective and hence, provisional) that early salvage radiotherapy is associated with improved prostate cancer–specific survival, and the magnitude of the survival benefit is similar to that observed in adjuvant [supplemental] radiotherapy trials. These data suggest that men for whom salvage radiotherapy is most beneficial are those with a PSA doubling time of less than 6 months, who also undergo treatment within 2 years of an increase in PSA level. If validated in other settings, these results could motivate a clinical trial comparing adjuvant with salvage radiotherapy, with prostate cancer–specific survival and overall survival as the primary end points.”

(JAMA. 2008;299[23]:2760-2769.)