Obesity May Affect Prostate Cancer Test

Obese men may have prostate cancer despite relatively low values on the prostate cancer screening test, a new study suggests. The PSA test detects PSA – prostate-specific antigen – in the blood. Only prostate cells give off PSA, and levels of the hormone can rise as prostate tumors grow.

Earlier studies showed that obese men have slightly lower PSA concentrations than lean men do. It’s not clear why this is so. New findings from Duke University researcher Stephen J. Freedland, MD, and colleagues now suggest an answer.

“Being a big guy, you have enormous blood volume, so PSA is diluted,” Freedland said. “Obese men having these lower PSA values due to the dilution factor means we are going to miss some of them early on.”

Other recent studies have shown that obese men have a higher risk of dying from prostate cancer than other men, and a delay in cancer detection may be part of the reason.
Results of the study were published in the November 21 issue of the Journal of the American Medical Association.

Study links being overweight to prostate cancer survival rate

The New York Times (11/13, Bakalar) reports on a new study which suggests that “overweight men with advanced prostate cancer” do not live as long as patients with normal body mass. For the study, which was published online Monday, and is “scheduled to appear in the Dec. 15 issue of the journal Cancer, lead author Matthew R. Smith, M.D., an oncologist at Massachusetts General Hospital in Boston, and colleagues, looked at 788 men” receiving “different types of therapies for prostate cancer. More than 50 percent of them were either overweight or obese.”

Extra fat raised the risk of dying from the disease by 52 percent, and obesity increased it to 64 percent, after researchers adjusted for other medical reasons. According to Dr. Smith, the reasons for this are not fully understood. However, he speculated, “It may be that prostate cancer treatments are less effective in men who have higher weights, or that other illnesses these men may have — such as diabetes — play a role in the increased risk of prostate cancer death.”

Robotic Surgery May Improve Survival Rate For Prostate Cancer Patients

Performing less invasive laparoscopic surgery using robotic technology may improve survival rates for prostate cancer patients, according to a study by urologic oncologists at Thomas Jefferson University Hospital’s multidisciplinary Genitourinary (GU) cancer center.

In a study presented May 21, 2007 at the annual American Urological Society meeting in Anaheim, Calif., the Jefferson urologists found that performing a laparoscopic radical prostatectomy (LRP) with robot technology can reduce positive surgical margins. Positive surgical margins refers to when cancer, seen under a microscope, goes to the edge of a specimen, meaning that cancerous cells likely remain in the patient. LRP is the surgical removal of the entire prostate gland and surrounding tissue including the seminal vessels through several tiny incisions. “We demonstrated a significant improvement (lowering) in the positive surgical margin rate with the addition of robotics to an established LRP,“ said Costas Lallas, M.D., assistant professor of Urology, Jefferson Medical College of Thomas Jefferson University, one of the investigators.

Laparoscopic surgery has proven to offer potential advantages to patients including less trauma through smaller incisions, faster recovery and less overall blood loss during surgery, allowing most patients to leave the hospital in one day. The robotic system further refines laparoscopic prostatectomy by allowing a surgeon’s hand movements to be scaled, filtered and translated into precise movements of micro-instruments within the operative field. The magnified, three-dimensional view the surgeon experiences enables him to perform precise surgery in complex procedures, such as radical prostatectomy, through small surgical incisions.

MBUA have been performing robot-assisted laparoscopic radical prostatectomy since 2003, and are the only urologists in the Monterey Bay area who perform robotic prostatectomy using the da Vinci Surgical System. Our experience is the same as reported in this study and others; patients recover much faster after robotic prostatectomy than after open surgery, and the cancer cure rate, and recovery of normal urinary and sexual function are superior compared to open prostate cancer surgery.

Outcomes comparable for cryosurgery and radiation therapy in prostate cancer

After nearly 7 years of follow-up, cryoablation appears to be as effective as external beam radiation therapy (EBRT) in the treatment of localized prostate cancer, according to the results of a prospective, randomized trial by researchers at the University of Calgary, Alberta, Canada.
No evidence of disease progression—defined as no biochemical evidence of progression, no radiologic evidence of metastasis, and no need for secondary treatment—is the primary efficacy endpoint for the study.

With a median duration of follow-up of 82 months, the rates of no evidence of disease progression in the cryoablation and EBRT groups were 75.7% versus 73.9% at 36 months, 72.7% versus 61.6% at 48 months, and 70.4% versus 58.3% at 60 months. The differences between groups are not statistically significant; however, there is a trend favoring cryoablation over EBRT at 48 months and 60 months, and a statistically significant difference favoring cryoablation over EBRT in the secondary endpoint of persistence of local control at 36 months (negative 10-core transrectal ultrasound-guided biopsy rates, 93.5% vs. 73.3%).

“Controversy continues over what constitutes optimal treatment for localized prostate cancer as there remains a conspicuous lack of randomized trials directly comparing different modalities,” said lead author Bryan J. Donnelly, MD. “Our experience with accrual underlines that such head-to-head studies are difficult, but can be done, and the results from this study to date suggest cryoablation and EBRT can be considered similarly effective.”

New Blood Test for Prostate Cancer Showing Promise

A new blood test, called EPCA-2, is showing potential as a screening blood test for prostate cancer. It is hoped that the EPCA-2 test will be more accurate than the current test, PSA, and detect more cancers with fewer negative biopsies. While screening for prostate-specific antigen (PSA) has been the standard of care for more than 2 decades, it is not specific for prostate cancer, and raised concentrations have been linked to other prostate conditions such as benign prostatic hyperplasia and prostatitis. Several groups have been working to identify new biomarkers for prostate cancer, and this latest effort, published in the April issue of Urology, shows that EPCA-2 has potential as a new serum-based test.

Due to elevated PSA levels, an estimated 1.6 million men undergo prostatic biopsies in the United States every year. Approximately 60% of these patients have negative results, reports a news release about the study. Conversely, about 15% of men with prostate cancer go undetected because their PSA levels are below the cutoff level. The most recent study showed negative results in normal men 92% of the time, meaning that few men without cancer would have an elevated test and undergo biopsy. The study also found that 94% of men with cancer had an elevated test and would be biopsied, and few men with cancer would be missed by the test.

EPCA-2 is the second prostate-cancer marker identified by the same researchers that has outperformed PSA. Last year, the team identified a tissue-based test, EPCA-1, that also proved effective in flagging prostate cancer. The only similarity between these markers is that they were discovered using the same approach. The efficacy of EPCA-1 as a test of biopsy samples is currently being studied.

“A blood test based on EPCA-2 may greatly improve our ability to accurately detect prostate cancer early, minimize the number of false positives, and lower the number of unnecessary biopsies,“ senior author Robert Getzenberg, PhD, from the Brady Urological Institute at Johns Hopkins Hospital, in Baltimore, Maryland, told reporters. “In addition, this is the first time we have a test that effectively distinguishes between men with cancer confined to the prostate and those whose disease has spread outside the gland.“

The investigators report, “The results of our study have shown that EPCA-2 is a novel biomarker associated with prostate cancer that has high sensitivity and specificity and accurately differentiates between men with organ-confined and non–organ-confined disease.“ Dr. Getzenberg says larger clinical trials for EPCA-2 are planned that could make this test available in about 18 months.

Surgery or Radiation improves survival compared to observation of localized prostate cancer.

A recently published study analyzed the outcomes of 3,159 men treated either conservatively or with radiotherapy or radical prostatectomy (RP) in the years 1980 to 1997. The study shows that men with localized prostate cancer treated with surgery (radical prostatectomy, RP) or radiation had improved survival compared to men who chose observation, despite the fact that the men who chose treatment had more aggressive cancers.

Participants were younger than 75 years and had socioeconomic, clinical, pathological and demographic data reviewed. Men with positive bones scans were excluded. The primary endpoint was death from all causes and the secondary endpoint was death from prostate cancer. Radiotherapy or RP had to be received by the patient within 6 months of diagnosis.

Surgery reduced the 15-year mortality rate by 59% overall and by 47%, 60%, and 65% for men with grade 1, 2, and 3 tumors, respectively. The overall survival advantage was 8.6 years and was 6.8, 5.5, and 10.4 years for patients with grade 1, 2, and 3 disease, respectively. Radiotherapy patients also experienced a survival advantage with a reduction in mortality of 33%. The survival advantage was also found for CaP-specific survival. Radiotherapy or RP reduced the death rate from CaP by 38% and 63%, respectively, compared with patients treated conservatively.

These results may seem obvious, but there is vigorous ongoing debate about the benefit of aggressive treatment of localized prostate cancer. This is just the latest in a series of studies that show an advatage for treatment, particularly in younger patients and men with at least 10 years of life expectancy.

Pomegranate Juice May be Good for the Prostate and Heart

Few American men have heard of the pomegranate, and fewer still have eaten this curious-looking fruit loaded with red seeds. But new scientific findings suggest that pomegranates may one day find a place in healthful diets, reports the April 2007 issue of Harvard Men’s Health Watch.

Two recent studies suggest that pomegranate juice may help fight prostate cancer. In one study, scientists grew cells from highly aggressive cases of human prostate cancer in tissue cultures. Pomegranate fruit extracts slowed the growth of the cultured cancer cells and promoted cell death. The researchers then implanted the cancer cells in mice. A group of mice that received water laced with pomegranate juice developed significantly smaller tumors than the untreated animals. In a preliminary study of men with prostate cancer, pomegranate juice lengthened patients’ PSA doubling time (the longer the doubling time, the slower the tumor is growing) from 15 months before treatment to 54 months on the juice.

Preliminary results in test tubes, animals, and humans suggest that pomegranates may also have beneficial effects on cardiovascular disease. However, preliminary research also suggests that pomegranate juice may interact with certain medications, much like grapefruit juice does.

The bottom line: Early studies raise hopes that pomegranates may have potential benefits for prostate cancer and heart disease, but more research is needed to determine whether these hopes are justified.

PCA3 test can help to identify men with prostate cancer

The MBUA urologists are now offering men a new test for prostate cancer, called PCA3. This test is used for men who have an elevated PSA and a negative prostate biopsy. The test is done in the office on a urine specimen, and can help us decide which patients should have a repeat prostate biopsy and which can be safely followed. Feel free to discuss this with one of our urologists.

Regular screening cuts risk of advanced prostate cancer

A Swedish study of 20,000 men shows that prostate cancer screening every two years cut the risk of metastatic prostate cancer by 50% or more (European Urology, 2007; 51:659-664). In the study 9,972 men were offered regular screening, and 9,973 men were not screened. Twice as many cancer cases were diagnosed in the screened group, but the risk of advanced prostate cancer in the men who complied with regular screening was decreased by 2/3 compared to the men who were not screened. The average survival of men with metastatic prostate cancer is 3.5 yrs, so prostate cancer screening should decrease the risk of death from prostate cancer in men with a longer life expectancy. MBUA recommend prostate cancer screening in all men after age 40 and until they are no longer in good health.

High Zinc intake linked to advanced prostate cancer

A study in Europe of men with prostate cancer showed that men with the highest zinc intake had a two-fold increased risk of aggressive or advanced prostate cancer. Zinc has been advocated as a beneficial supplement for the prostate because the prostate has higher levels of zinc than other tissues, but this study suggests that increased zinc intake may be harmful. Other studies have suggested that increased zinc intake may play a role in benign prostate enlargement.