Periprostatic Fat

[pjoshea13]

This post is prompted by a new study.

For years, PCa studies have warned that obesity is associated with a poor outcome. As though a BMI < 30 is somehow protective. There have been some who have rejected BMI as a measure, preferring the waist:hip ratio. The impression has been given that the risk is in the belly fat we can squeeze between our fingers.

The real risk is invisible: visceral fat. There is an assumption that men who are fat on the outside must be fat inside. This is not always true.

[1] From Wikipedia: "The term TOFI, “thin-outside-fat-inside” is used to describe lean individuals with a disproportionate amount of fat (adipose tissue) stored within their abdomen. The figure to illustrate this shows two men, both aged 35 years, with a BMI of 25 kg/m2. Despite their similar size, the TOFI had 5.86 litres of internal fat, whilst the healthy control had only 1.65 litres."

"No less important than the TOFI are the metabolic opposites. The subjects have variously been described as being 'FOTI' (fat outside, thin inside), the “metabolically healthy obese” (MHO) or even the fit fat. These subjects have little internal fat relative to their size"

If visceral fat is the real health hazard, the fat around the prostate (periprostatic fat) may be particularly so for prostatic health.

Unfortunately, one needs a scan to assess periprostatic fat. (Or a prostatectomy, of course. LOL)

The primary cause of visceral fat is elevated triglycerides. The ideal number might be close to the HDL-cholesterol value. The triglycerides:HDL-C ratio is a surrogate for insulin resistence. >2 is unsafe & >3 is a serious problem IMO.

Elevated triglycerides are mostly due to a high dietary carbohydrate:fat ratio.

The reason that periprostatic fat may be dangerous, is that it acts as though it were a gland in the endocrine system. It secretes hormones.

The literature (38 hits on PubMed) goes back 30 years, but I'll deal with recent studies.

[2] (The new study.) (2016 - U.S.)

"Obesity has been correlated with high grades of prostate cancer. Body mass index and waist circumference are not good surrogates for obesity."

"A total of 295 consecutive patients (Median age 64, range 38-84) underwent mpMRI of the prostate gland between August 2013 and February 2015. All patients underwent a 3 Tesla multi-parametric MRI. Using DynaCAD (Invivo, Gainesville Florida, USA), we calculated the prostate volume and volume of the periprostatic fat seen on mpMRI. The peri-prostatic fat ratio was calculated using the formula peri-prostatic fat volume / prostate volume)."

"A higher periprostatic fat volume ... and a higher periprostatic fat ratio ... were significantly associated with a higher Gleason Score."

"There was no correlation observed between periprostatic fat ratio and PSA .., age ... or BMI ..."

[3] (2014 - China)

"In recent years, the relationship between obesity and cancer has drawn significant academic interests. Epidemiological studies have demon- strated that obesity is a risk factor of breast, endometrium, kidney and gallbladder cancers, but its role in PCA etiology remains elusive. Obesity is often assessed by BMI, which comes from physical measurement or self-reported height and weight. However, the BMI, which is a marker for overall obesity, cannot distinguish between ad- iposity and lean body mass, particularly in men with greater muscle mass, nor does it reflect fat distribution. Therefore, the link between BMI and PCa is controversial in many studies. In our research, no association between BMI and PCa risk was revealed, and BMI was not an independent risk factor for PCa aggressiveness."

"Abdominal adiposity or periprostatic adiposity has been found to pre- cisely reflect the association between obesity and PCa in recent years. Although abdominal fat make up only 10% of total body fat, it is metabolically more active than subcutaneous or peripheral fat. Furthermore, periprostatic fat is associated with fluctuation in levels of several hormones, including insulin, testosterone, estrogen, sex hormone binding globulin, and leptin which play a significant role in the biology of PCa."

"In our study, MRI is proved to be a precise way to measure the periprostatic adiposity. We could clearly distinguish the fat, muscle and bone. By measurement of abdominal adipose distribution, reflecting the periprostatic fat, we have found a close association between periprostatic adiposity (the PFA and ratio) and PCa aggressiveness as well as PCa risk."

"The periprostatic adiposity not only affects the PCa aggressiveness, but also has effect in accurate assessment of the tumor stage and grade. We should predict the prognosis of patient with {prostatectomy} by measuring periprostatic adiposity on pre-operative MRI."

[4] (2014 - China)

"The relationship between obesity and prostate cancer aggressiveness is controversial in recent studies, partly because BMI is the only generally applied marker of obesity. Our study aimed at evaluating the correlation of periprostatic fat (PF) on magnatic resonance imaging (MRI) and adipocytokines with prostate cancer aggressiveness."

"more adipose tissue was distributed in periprostatic areas of high risk patients."

"The levels of IL-6, leptin and c-reactive protein (CRP) significantly increased with the aggressiveness of prostate cancer, and also with PF and its ratio. The strongest correlation was seen between IL-6 and PF"

"Periprostatic adiposity not only affects prostate cancer aggressiveness, but also influences the secretion of adipocytokines."

[5] (2011 - Netherlands)

"Nowadays more and more publications have been published about the topic prostate cancer aggressiveness and obesity with mixed results. However, most of the publications used the BMI as a marker for obesity, while the most metabolic active fat is the visceral fat."

"... revealed a significant association between periprostatic fat density (PFD) and risk of having a high risk disease."

"Patients with a higher PFD had more often aggressive prostate cancer."

...

& so on. No use piling on studies that say the same thing.

There are implications for those who still have an intact prostate. But also for those who have visceral fat around other organs, since that fat is metabolically active too.

Addressing a triglycerides issue by avoiding low-fat / high-carb meals & snacks is perhaps an option. Metformin to control insulin. etc.

-Patrick

[1] en.wikipedia.org/wiki/TOFI

[2] ncbi.nlm.nih.gov/pubmed/275...

[3] urologyjournal.org/index.ph...

[4] ncbi.nlm.nih.gov/pubmed/246...

[5] ncbi.nlm.nih.gov/pubmed/210...

[BigRich]

Patrick,

I have lost a 100lbs. I have another 25 lbs to go. It is hard to lose excess weight. I did it through diet only, no drugs. In having incureable PCa; I am trying to be a marthon man, 26 years of life, 8 more years to go.

Rich

[Hidden]

I was always skinny as a kid. I continued to think of myself as 'not-fat' despite having a belly and being just over the BMI threshold of being overweight. I am 66 and sitting here with prostate cancer. I am 6'4' and I've lost 15 lbs this year to get down to 193 ... and I still have a belly. One other thing I can mention this is probably related -- I've resisted, until this year, getting on statins. I've seen claims that statins can help prevent prostate cancer. Now I am kicking myself on that score, and for accumulation fat that I knew was unhealthy. Thanks for your diligent research.