By Amy Norton
HealthDay reporter
MONDAY, July 12, 2021 (HealthDay News) – If men have advanced prostate cancer, obesity could offer a survival benefit, a preliminary study suggests.
Researchers in Italy found that men with prostate cancer who had spread throughout their bodies were less likely to die of obese people in the next few years.
About 30% were still alive after three years, versus 20% of normal-weight and overweight men, the study found.
The researchers stressed that nobody advises men to put on extra pounds to fight off prostate cancer: obesity is linked to a higher risk of developing and dying from various chronic diseases, including a number of cancers.
But over the years, some studies have found that cancer patients with higher body mass index (BMI) tend to survive longer – a phenomenon sometimes referred to as the “obesity paradox”.
The new evidence suggests that the paradox could also apply to advanced prostate cancer.
However, an expert not involved in the study cautioned caution in drawing conclusions.
Crucially, the reasons for the obesity or thinness of the study patients are not clear, explained Dr. Vinayak Wagaskar, a urologist at the Icahn School of Medicine on Mount Sinai in New York City.
He found that BMI wasn’t measured until after the men developed advanced cancer that no longer responded to hormone therapy – and not right after they were diagnosed with prostate cancer.
This is important in part because certain treatments for prostate cancer – including hormone therapy and steroid drugs – can lead to weight gain.
In addition, Wagaskar said, additional medical conditions may have affected patients’ weight.
He said the study brought up “an interesting concept” but emphasized the need for more research – using men’s BMI measured at the time of diagnosis.
For the study, Dr. Nicola Fossati and colleagues from the University of San Raffaele in Milan provide data from nearly 1,600 men who have participated in previous clinical trials. All patients had metastatic prostate cancer that was unresponsive to hormone therapy. Metastatic means that it has spread to distant places in the body.
While prostate cancer is treatable in its early stages, metastatic cancer is different: According to the American Cancer Society, about 30% of men with such advanced disease survive five years.
In that study, Fossati’s team found that men with a BMI of 30 or higher – the obesity threshold – died 29% less often than men with a lower BMI within three years.
The results were presented online on Sunday at the annual meeting of the European Association of Urology (EAU). Research presented at meetings is generally considered preliminary until published in a peer-reviewed journal.
In a press release from the meeting, Fossati said, “This obesity paradox has been seen in a number of other cancers, possibly due to the relationship between tissue fat and cancer genomes, and more research is needed in this area.”
On the other hand, he said, the results may reflect an interaction between the cancer chemotherapy and other drugs.
“Obese patients in this age group typically take drugs for other conditions,” noted Fossati, “and we don’t fully understand how these drugs are linked.”
Dr. Peter Albers, chairman of the Scientific Congress Bureau of the EAU, also warned that the reasons for the obesity paradox in general are uncertain.
“It could be that patients with a higher BMI are better able to tolerate the toxicity of the treatments and their side effects,” Albers said in the press release. “In prostate cancer, it could be due to the protective effects of hormones found in tissue fat; and it is known that healthy men with a slightly higher BMI have a higher overall life expectancy than very lean ones.”
But, he emphasized, these are all assumptions.
“More research is needed to identify the biological mechanism behind these disparate results,” said Albers. “Until this mechanism is proven, we cannot recommend any change in treatment for patients with advanced prostate cancer.”
In fact, according to Wagaskar, some other studies have linked obesity not only to a higher risk of developing prostate cancer, but also to “worse cancer-related outcomes.”
Fossati agreed that a healthy weight range should be the goal. “Obesity is a risk factor for many cancers and other diseases,” he said, “and patients should always aim for a healthy BMI of 18-24.”
More information
The American Cancer Society has more about the causes and prevention of prostate cancer.
SOURCES: Vinayak G. Wagaskar, MBBS, MCh, Lecturer, Department of Urology, Icahn School of Medicine at Mount Sinai, New York City; Annual meeting of the European Association of Urology, press release and online presentation, July 11, 2021
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