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Obesity Affects Radiation Treatment for Prostate Cancer
Obese men with prostate cancer are less likely to benefit from radiation therapy than men who are not overweight, according to a report in the journal Cancer.
The finding may help physicians determine which patients, particularly overweight ones, need to have more aggressive treatment.
"Prostate cancer for most men is quiet," says study lead author Sara Strom, Ph.D., of the University of Texas M.D. Anderson Cancer Center.
"It's a cancer with a good outcome," she says. "Basically, what you would like in prostate cancer is to identify men who have more chances of having a bad outcome, so you can do something different with them. Obesity is something to take into consideration.”
Obesity is the root of many health evils, from diabetes to joint problems and, as is increasingly evident, even cancer.
Previous studies have shown that obese men with prostate cancer tend to have more aggressive disease and higher death rates.
They are also more likely to have a malignancy that progresses after a prostatectomy, which is surgery to remove all or part of the prostate.
Researchers still do not know how obesity might affect disease progression after radiation treatment.
The new study sought to examine any relationship between obesity and progression of disease after external-beam radiotherapy. It is the first study of its kind.
Dr. Strom reviewed the medical records of 873 prostate cancer patients who had received external beam radiotherapy as the only treatment for their illness. Eighteen percent of the men in the group were mildly obese, and 5 percent were moderately to severely obese.
As the patient's body mass index (BMI, a ratio of weight to height) increased, the risk of disease progression following radiation therapy also increased.
Moderately and severely obese men had a 99 percent greater risk of higher levels of prostate-specific antigen (PSA), a protein linked to the presence of prostate cancer. The obese men also had a 70 percent greater risk of tumor recurrence or metastasis.
"We found that after taking all the other important risk factors for a bad outcome into consideration, obesity is still associated with an increased risk not only of PSA going up but of having a cancer that returns and, in some cases, becomes metastatic," says Dr. Strom. "That's really the bad outcome.”
The study did not explore the reasons behind the findings, but Dr. Strom speculates that hormones, diet, and genetic susceptibility may all play a role.
But another expert cautions restraint when looking at the findings.
"Not many of the patients in the study were obese, so you can't make a very strong case for this paper, even though it's possible it's true," says Dr. Murugesan Manoharan, of the University of Miami Miller School of Medicine.
"The study was also done in the past [1988-2001], and things have changed since them," he notes. "We have newer radiation technologies."
A second study in the same issue of the journal found that men with prostate cancer were driven more by emotion than any clear understanding of the clinical evidence when making their treatment decisions.
A study of 20 men with prostate cancer revealed a high level of fear and uncertainty, along with a desire to have rapid results and a tendency to shun second opinions.
Men also displayed misconceptions about the effectiveness of different treatment options and tended to rely on anecdotal information about others' experiences with the disease.
Physicians need to take patients' fears and misconceptions into account when guiding treatment, the authors state.
"Ideally, patients should make at least two visits, one for diagnosis and an overview of treatment," Dr. Manoharan says. "Then, bring them back after two weeks, after they have reviewed written information.
"Prostate cancer does not kill anybody so rapidly, so time is on the side of the patients," explains Dr. Manoharan. "Patients should be given the important information that this cancer is not going to kill them immediately."
Always consult your physician for more information.
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The fear of having prostate cancer can be devastating to men. However, it is most successfully treated when found early.
The American Cancer Society (ACS) states that nearly 86 percent of all prostate cancers are discovered while they are either localized (confined to the prostate) or regional (nearby).
The five-year survival rate for men diagnosed with prostate tumors discovered at these stages is 100 percent.
In the past 20 years, the five-year survival rate for all stages combined has increased from 67 percent to 99 percent.
Prostate cancer is the most common cancer among men, excluding skin cancer.
ACS estimates for 2006 include 234,460 new cases of prostate cancer in the US.
Year 2006 estimates include 27,350 deaths occurring from prostate cancer in the US alone, making it the second leading cause of cancer death in men.
There are usually no specific signs or symptoms of early prostate cancer - which is why prostate screening is so important.
An annual physical examination, prostate-specific antigen (PSA) blood test, and digital rectal exam (DRE) provide the best chance of identifying prostate cancer in its earliest stages.
The following are the most common symptoms of prostate cancer:
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weak or interrupted flow of urine
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urinating often (especially at night)
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difficulty urinating or holding back urine
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inability to urinate
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pain or burning when urinating
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blood in the urine or semen
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nagging pain in the back, hips, or pelvis
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difficulty having an erection
The symptoms of prostate cancer may resemble other conditions or medical problems. Always consult your physician for a diagnosis.
As a man gets older, his prostate may grow bigger and obstruct the flow of urine, or interfere with sexual function.
An enlarged prostate gland - a condition called benign prostate hyperplasia - may require treatment with medicine or surgery to relieve symptoms.
This common benign prostate condition, which is not cancer, can cause many of the same symptoms as prostate cancer.
Always consult your physician for more information. |
