Oct 11, 2005
Discovery of Mechanisms inhibiting prostate cancer development
Prostate cancer is caused by changes in several tumor suppressor genes including PTEN and p53. Up to 70 percent of men with prostate cancer have lost one copy of the PTEN gene at the time of diagnosis, and p53 is absent in a high number of patients with advanced prostate cancer.
Scientists at Memorial Sloan-Kettering Cancer Center have found an unexpected effect of the interaction of these two genes in early stage prostate cancer. In a study published in a recent issue of Nature, researchers found that prostate tumor growth is arrested through a biological process called cellular senescence, in which cells stop proliferating and remain alive but fail to respond to normal growth signals.
Researchers suggest that drugs that support p53 function could delay progression of prostate cancer in PTEN -deficient prostate cancer by triggering cellular senescence. Acute loss of PTEN results in increased, not decreased p53 function.
"This works to suppress the further development of cancer," said Pier Paolo Pandolfi, MD, PhD, Head of the Molecular and Developmental Biology Laboratory at Memorial Sloan-Kettering and the study's senior author. "If we can maintain a higher level of p53 in prostate cancer and induce cellular senescence, the disease should remain stable".
Oct 6, 2005
Hormone therapy improves survival in localized prostate cancer
Patients who have advanced prostate cancer confined to the prostate, radiation treatment in combination with a six-months of hormonal treatment can improve survival by as much as 50 percent, as per the new research results.
Although hormone therapy is now standard treatment for metastatic prostate cancer, whether it is beneficial in treating prostate cancer still confined to the organ has been less clear. Also it was not clear if a short-term hormone therapy might be effective in this setting since, most patients now receive the treatment over a period of at least three years.
"Finding that we can stop cancerous progression in 40 percent of men by just six months of testosterone suppression treatment with minimal side effects is enormously important," said study author Dr. Jim Denham, from the Trans-Tasman Radiation Oncology Group and University of Newcastle, New South Wales, Australia.
In their study, Denham's team randomly assigned 818 men with locally advanced prostate cancer to radiation treatment with no testosterone suppression, or three months or six months of testosterone suppression.
Reporting the recent online edition of The Lancet Oncology, the Australian team found that men treated with three months of hormone therapy before and during radiation were at a 35 percent lower risk of relapse compared to men receiving radiation alone. For men treated with six months of hormone therapy before and during radiation, that risk of relapse was reduced by 44 percent.
In addition, survival among men receiving both radiation and hormone treatment was 54 percent better compared with men who received radiation alone, according to the report.
Oct 3, 2005
Increase in weight May Stimulate Prostate Cancer
Researchers have reported that a man's weight when he's diagnosed with prostate cancer, along with his history of weight gain, may play a key role in his prognosis.
The study of 526 prostate cancer patients found that those who were obese (body mass index of 30 or more) when diagnosed were more likely to experience "biochemical failure" than patients who weren't obese.
Biochemical failure in the form of rising level of prostate specific antigen (PSA) in the blood can indicate that cancer is advancing.
Researcher Sara Strom, an associate professor of epidemiology at the University of Texas M.D. Anderson Cancer Center in Houston has explained that after surgery, a patient's PSA should go back to being undetectable, but if it begins to rise, that is an indicator of progression.
Men experiencing the greatest rate of weight gain between age 25 and the time of their prostate cancer diagnosis experienced disease progression much sooner (average of 17 months) than men who gained weight more slowly (average of 39 months).
The result of the researchers suggests that diet and exercise may be effective in reducing the risk of prostate cancer progression.
The study has appeared in a recent issue of Clinical Cancer Research.
Sep 30, 2005
PSA is Still Best Predictor of Prostate Cancer Recurrence
Measuring the blood protein prostate specific antigen (PSA) is still the best method of predicting the likelihood of cancer recurrence after prostate cancer surgery, according to a Johns Hopkins University study appearing in the October issue of the Journal of Urology.
The finding counters recent claims by some experts that PSA tests may not be effective in predicting prostate cancer risk. PSA is a protein produced by the prostate gland that increases in the presence of prostate cancer.
The study of more than 2,300 men concluded that those with high PSA levels before prostate-removing surgery were much more likely to have advanced cancer, and evidence of higher-grade cancers in tissue removed during the surgery.
Increasing PSA levels were significantly associated with increased risk of cancer recurrence after prostate surgery, even in men who had lower PSA levels before surgery, the study found. Men with PSA levels of 20 nanograms per milliliter were five times more likely to develop cancer after surgery than men with PSA levels of less than 10 nanograms per milliliter.
Sep 26, 2005
Pomegranate juice to prevent prostate cancer
Eat lot of pomegranate to prevent or treat prostate cancer! That may be the message based on the latest research from UW Medical School. As per these researches the juice of pomegranate holds a major promise to combat prostate cancer.
Earlier research at Wisconsin and elsewhere has shown that the pomegranate is rich in anti-oxidant and anti-inflammatory activity and is effective against tumors in mouse skin. In fact, pomegranate juice has higher anti-oxidant activity than do red wine and green tea, both of which appear promising as anti-cancer agents.
Using human prostate cancer cells, the UW research team first evaluated the fruit extract's effect, on cells cultured in laboratory dishes and found that the higher the dose of pomegranate extract the cells received, the more cells died.
The research team conducted tests in mice that had been injected with prostate cancer cells from humans and developed malignancies. The 24 mice were randomly divided into three groups. The control group received normal drinking water, while the animals in the second and third groups had their drinking water supplemented with .1 percent and .2 percent pomegranate extract respectively. These doses for the mice were chosen to parallel how much pomegranate juice a typical healthy human might be willing to eat or drink daily.
The results were dramatic: the mice receiving the higher concentration of pomegranate extract showed significant slowing of their cancer progression and a decrease in the levels of prostate-specific antigen (PSA). The animals that received only water had tumors that grew much faster than those in the animals treated with pomegranate extract.
Sep 25, 2005
UC Explores new treatment combination for prostate cancer
A new approach is underway for the treatment of patients with prostate cancer. This new approach consists of a combination of chemotherapy, hormonal therapy and a new, targeted drug. Patients will also get agents that would strengthen the bone together with this treatment. Dr. Leslie Oleksowicz, director of the Medical Genitourinary Oncology Program at UC, is the physician developing this new approach.
"When a woman has a breast cancer tumor removed, we immediately administer chemotherapy and hormones to kill residual, microscopic tumor cells, thereby eliminating further growth," Oleksowicz said. "If the same method is applied to prostate cancer and is effective, it would shift the way we approach overall treatment of this disease."
Oleksowicz said that this is the first study of chemotherapy plus targeted anti-tumor therapy as an early approach to prostate cancer treatment. The new combination will be tested on men, previously treated with surgery or radiation, and are currently experiencing a rising prostate-specific antigen (PSA) level.
Sep 21, 2005
New Test May Improve Prostate Cancer Detection
A new test that looks at the immune system's response to prostate cancer is better at diagnosing the malignancy than the current standard, the prostate-specific antigen (PSA) test, as per findings from a new study.
This test could someday be used to answer the most critical question when prostate cancer is diagnosed - whether the tumor is so aggressive that surgery should be done, or whether watchful waiting will do, says Dr. Arul M. Chinnaiyan, a professor of pathology at the University of Michigan Medical School, who led the study. These findings are published in the Sept. 22 issue of the New England Journal of Medicine.
"What we are doing is taking advantage of the body's immune system, which ordinarily responds to anything foreign - viruses, bacteria, cancer," Chinnaiyan said. "As part of that response, the immune system produces antibodies against cancer proteins."
Chinnaiyan and his colleagues took samples of DNA from prostate cancer cells and put them into a virus. The cancer DNA produces proteins that differ from the proteins normally found in the body. The researchers then put the information about 22 of those cancer proteins onto an electronic chip and tested 128 blood samples, 60 from men with prostate cancer, 68 from men without the cancer.
The test did better at detecting prostate cancer than a PSA test conducted on the same samples - 93 percent accuracy for the new test, compared to 80 percent accuracy for the PSA test, the researchers reported.
Sep 21, 2005
High-dose radiation reduces prostate cancer return
Men who have localized prostate cancer can benefit from high-dose external radiation therapy, according to a new study.
Prostate cancer can be treated by either conventional dose radiotherapy or by newer methods involving higher doses. The problem with the higher doses is there is a risk of adverse effects on neighboring normal tissue.
However, more accurate techniques have been developed which allow more focused delivery of radiation - together these are known as 'three-dimensional conformal therapy'. Now researchers at Massachusetts General Hospital and Harvard Medical School report on whether these higher doses can prevent recurrence.
They looked at 393 patients with prostate cancer who received either conventional or high-dose radiotherapy. At five years, 61.4 per cent of those having conventional radiotherapy were free of disease as determined by prostate specific antigen levels. For those on high-dose radiotherapy the figure was 80.4 per cent. Only one per cent of those on conventional dose therapy and two per cent on high-dose therapy had acute side effects. The study suggests that high-dose radiotherapy is indeed useful in preventing recurrence of prostate cancer.
Sep 21, 2005
Prostate cancer awareness month
September is prostate cancer awareness month. At this time it is to be remembered that prostate cancer is the most common type of cancer that affect American men. An estimated 230,000 men are diagnosed with prostate cancer each year.
The disease is most common in men 65 and older and among African-American males, but it's important for men over the age of 50 to have a regular prostate exam and undergo a prostate specific antigen blood test to establish a baseline PSA level so your doctor can monitor any changes.
African-American men or men with a family history of the disease should begin regular prostate screening exams at an earlier age.
Signs and symptoms of prostate cancer include changes in urinary flow (such as increased frequency, urgency or hesitancy), frequent nighttime urination, painful urination and blood in the urine.
The treatments for prostate cancer include external beam radiation therapy, radiation seed implants, proton beam therapy, hormone therapy, surgery and watchful waiting. A combination of these treatments may be ordered for the patient, depending on the diagnosis and whether the cancer has spread from the prostate to other parts of the body.