University of Colorado researchers may have discovered why some early stage prostate cancers progress while others don’t. The difference may lie in a high-fiber diet.

The study using mice models with prostate cancer compared mice fed a major component of high fiber diets called inositol hexaphosphate (IP6), with mice that were not. MRI scans were then used to monitor the progression of their cancer.

By the end of the study, mice receiving IP6 had dramatically smaller tumors, primarily due to the anti-angiogenic effects of IP6. Angiogenesis is the process of forming new blood vessels to supply nutrients and oxygen to the tumor so it can grow and metastasize. By preventing angiogenesis, IP6 essentially cut the blood supply to the point that it "starved" the tumor.

In addition, treatment with IP6 slowed the rate at which prostate cancers metabolized glucose. Researchers believe that a possible mechanism for this effect may involve a reduction in a protein called GLUT-4, which is instrumental in transporting glucose.

This research may explain a long standing mystery: Prostate cancer occurrence in Asian cultures is similar to the rate in Western cultures, but in the West, prostate cancer tends to progress, whereas in Asian cultures it does not. Why?

Researchers had been looking for genetic variations between Asian and Western peoples that could explain the difference in prostate cancer progression rates, but now it seems as if the difference may not be genetic but dietary. Asian diets include high amounts of IP6 whereas Western diets generally do not.

Sources of IP6

Inositol hexaphosphate (IP6) is a chemical found in beans, brown rice, corn, sesame seeds, wheat bran, and other high-fiber foods.

Source:

University of Colorado Cancer Center

National Cancer Institute

Separate studies have found that aspirin and tamoxifen, a drug initially developed for breast cancer, may be effective treatments for prostate cancer.

One study found that among men with prostate cancer, those who took aspirin for other medical conditions were nearly half as likely to die of their cancer as the men who didn’t take aspirin.

The study involved nearly 6,000 men of which about one-third were taking aspirin or other anticoagulants. Over 10-years, the researchers calculated, the prostate cancer death rate for those taking aspirin was 3 percent, compared with 8 percent for those who did not.

The aspirin users were also significantly less likely to experience a recurrence of prostate cancer or have the disease spread to the bones.

This research adds to the growing body of evidence that aspirin may be effective for many types of cancer throughout the body. Aspirin use has already been found to have an effect on colon cancer.

As for how aspirin works on cancer, Dr. Otis Brawley of the American Cancer Society said he believes that aspirin’s anti-inflammatory properties may play a role in the prevention of both heart disease and cancer.

“Inflammation may not cause a cancer, but it may promote cancer — it may be the fertilizer that makes it grow,” Dr. Brawley said.

Tamoxifen for Side-Effects

In the tamoxifen study, researchers analyzed the results of four independent clinical trials that examined the use of tamoxifen to manage the side effects of a common prostate cancer treatment, androgen-suppression therapy.

Androgen-suppression, which blocks testosterone activity, can slow the progression of advanced prostate cancer. But these drugs can cause side effects such as breast enlargement and pain that may stop men from undergoing the treatment.

During the one-year study, the researchers found that tamoxifen reduced the risk of breast enlargement and breast pain in men at quarterly exams compared to men who did not take tamoxifen. The drug was also minimized painful breast symptoms better than radiation therapy or treatment with the aromatase inhibitor anastrozole, which is also used to treat breast cancer.

As a result, few of the men treated with tamoxifen stopped taking their medication during their year of treatment. And there were no significant side effects of tamoxifen reported.

Sources:

PubMed

New York Times

BMC Medicine

New data on prostate cancer mortality rates is good information for men to know, but it may not make decisions about treatment any easier. Furthermore, the new research probably won’t end the longstanding debate in the medical community questioning the use of PSA screening for the cancer or whether or not to even treat the disease in some men.

According to the new study, if you have prostate cancer you have about an 11% chance that you’ll die from it. The odds are more likely that’s you’ll die of something else--like cardiovascular disease.

The study authors say their research reinforces the idea that the key to longevity is embracing an overall healthy lifestyle--like eating a balanced diet, managing your weight, getting regular exercise, and not smoking.

Study Details

The study used data from the U.S. Surveillance, Epidemiology, and End Results Program and the Swedish Cancer and Cause of Death registries to analyze the causes of death among more than 700,000 men. The U.S. data was for 1973-2008 and the Swedish data covered 1961-2008.

• Over these periods, 52% of the Swedish men with prostate cancer died and 30% of American men with prostate cancer in the study.
• Of these deaths, only 35% of the Swedish men died directly from prostate cancer and only 16% of American men died from the disease itself, the investigators found.
• As the study continued, fewer men died from prostate cancer while deaths from heart disease remained the same.
• By the last five years of the study, 29% of Swedish men with prostate cancer died from it as did 11% of American men, the researchers calculated.
• Deaths from prostate cancer varied by age and year of diagnosis. The most deaths were among older men and among men diagnosed before screening for PSA began, they added.

Clinical Implications

When doctors were asked to comment on the study findings, opinions varied widely. Some believe the study is justification for screening only high-risk men for prostate cancer, which includes African-American men and men with a family history of prostate cancer. Others like Dr. Durado Brooks, director of prostate and colon cancer at the American Cancer Society, argue against PSA screening saying that it too often "leads down the path of unnecessary treatment."

"Men should understand that not every prostate cancer needs to be found and every prostate cancer that's found does not necessarily need to be treated," he said.

With such diverse opinions in the medical community, it’s easy to see why men need all the information available to make a decision about their health. There just isn’t a clear-cut answer on this issue.

Source:

Health Day