Four (well, really six) ways you could limit your risk for lethal prostate cancer

A new paper in the Journal of the National Cancer Institute has suggested that strict adherence to a four-point healthy lifestyle may be able to lower risk for lethal forms of prostate cancer.

Specifically, the paper by Kenfield et al. identifies those four lifestyle factors as:

  • Not smoking
  • Maintaining a normal body mass index (i.e., a BMI of < 30)
  • Having a high level of physical activity (and yes that means getting sweaty on a regular basis), and
  • Ensuring a healthy diet

This paper is also discussed in a media release from the University of California at San Francisco.

We have known for a while that each of the above factors appears to have some degree of potential benefit in the prevention of risk for lethal forms of prostate cancer, but what Kenfield and her colleagues wanted to try to do was develop a “lifestyle score” that was associated with the prevention of potentially lethal prostate cancer.

To do this, they looked at data from men in the Health Professionals Follow-up Study or HPFS (42,701 men followed from 1986 to 2010) and then applied those data to men in the Physicians’ Health Study or PHS (20,324 men followed from 1982 to 2010). The study participants ranged in age from 40 to 84; they were all cancer-free at study enrollment; and each participant was given one point for meeting the following criteria:

  • Being a non-smoker or having stopped smoking at least 10 years earlier
  • Having a BMI < 30 kg/m2
  • Having a high level of vigorous physical activity

They could also receive one point each for having a diet that was

  • High in intake of tomatoes
  • High in  intake of fatty fish (e.g., salmon)
  • Low in intake of processed meat

This allowed the researchers to assign each participant a “diet only” score (from 0 to 3) and a total score (from 0 to 6).

Here is what they found:

  • There were  a total of 913 lethal prostate cancer events in the two health and lifestyle studies.
    • 576 occurred in the HPFS (1.35 percent of the participants)
    • 337 occurred in the PHS (1.66 percent of the participants).
  • Compared to men with 0 to 1 points in total,
    • Men in the HPFS with 5–6 points had a 68 percent lower risk of lethal prostate cancer (hazard ratio [HR] = 0.32).
    • Men in the  PHS with 5 to 6 points had a non-statistically significant 38 percent lower risk of lethal prostate cancer (HR = 0.62)
  • Compared to men with 0 points on the “diet only” scale,
    • Men in the HPFS with 3 points had a 46 percent lower risk of lethal prostate cancer (HR = 0.54)
    • Men in the PHS with 3 points had a non-statistically significant 30 percent lower risk of lethal prostate cancer (HR = 0.70).

According to Kenfield, they were also able to calculate

the population-attributable risk for American men over 60 and estimated that 34 percent of lethal prostate cancer would be reduced if all men exercised to the point of sweating for at least three hours a week.

Other findings reported include the following:

  • Vigorous exercise had the highest potential impact on prevention of lethal prostate cancer.
  • Men who had three healthy habit points were 30 to 46 percent less likely to develop lethal prostate cancer than the men with no points.
  • Eating at least seven servings of tomatoes each week lowered risk for lethal prostate cancer by 15 percent.
  • A single serving of fatty fish each week lowered risk for lethal prostate cancer by 17 percent.
  • Avoiding all processed meat lowered risk for lethal prostate cancer by 12 percent.
  • Among older American men with a long history of smoking, stopping smoking lowered risk for lethal prostate cancer by 3 percent.

However, having said all of this, we do have to point out that this is an epidemiological study, and so the findings show associations; they do not necessarily imply causes and consequent effects. On the other hand, we all know that not smoking, keeping one’s BMI down below 30, exercising regularly and vigorously, and having a healthy diet are good for us for all sorts of reasons. … It’s no unreasonable to think that these factors would affect risk for aggressive forms of prostate cancer too.

Your sitemaster would note that:

  • He stopped smoking nearly 20 years ago (after many prior attempts).
  • His BMI is 28.
  • He does his best to exercise vigorously for a couple of hours at least twice a week (although after 60 years of doing that it’s getting pretty boring)
  • He eats fatty fish like salmon and tomatoes frequently.
  • He almost never eats processed meats at all.
  • That gives him a “Kenfield healthy living score” of 6.
  • He has no sign of prostate cancer!

But then again … he did have a heart attack some years ago … so who knows what any of this really means!

11 Responses

  1. Are tinned tomatoes in chillis, etc., helpful? Does processed foods include red meat (defatted) and is this perceived as harmful as well? If one has low cholesterol of approximately 3.2 and attempts to eat less fats than normal but cannot exercise to a great extent but is not overweight and otherwise active, in a high risk category? Because of atrial fibrillation (chronic) and not permitted to take Cclcium, only vitamin D (Desunin 800 IU) and low-fat milk, cheese, and yogurt to compensate for calcium supplements. also take vitamin K2, and EPA capsules. Have had grade 3 prostate cancer, but have had steady PSA of 0.1 for several years. Was treated with HBRT and ADT for about 1 year, with some slight osteoporosis probably as a result of same, on bi-annual injections of denosumab for last 4 years. Am aged 72.

  2. Sitemaster:

    Thanks for sharing your own truthful score. I developed prostate cancer about 7 years ago. It was caught early and after several months of laborious researching of my treatment options, chose to have it surgically removed. I was lucky, I think, in finding a good surgeon who did a good job and left most of my other bodily “functions” fully working.

    Although I have exercised for years, tried to keep my weight close to “normal,” stopped smoking in 1990, and tried to eat healthy, I did for years eat high quality “deli” meat regularly for lunch. Since I was diagnosed with prostate cancer, I have had a strong feeling that sodium nitrates used to preserve processed deli meat caused my prostate cancer. I don’t know what the studies show, and have no real proof of the cause, but aside from eating processed meat, I would have easily fit the other criteria for the study, if I still had a prostate. This reinforces my belief that the preservative in processed meats likely caused my problem.

  3. Dear Mike:

    I think you are asking questions that you really need to be discussing with your doctors. My assumptions are that the research team probably included canned tomatoes as being acceptable and that by “processed meats” they were referring to things like spam and hot dogs and similar.

  4. Dear R:

    I know of no evidence that the various preservatives used in the preparation of processed meats (nitrates included) are specifically associated with risk for prostate cancer. Is that possible? Yes it is. However, I’d be very surprised if any clear determination that consumption of such preservatives was a singular cause of prostate cancer could be made.

    Please note that even if one follows all of the proposed guidance suggested in this study, it doesn’t reduce one’s risk of getting lethal prostate cancer to zero, and it also doesn’t imply that one might not be diagnosed with lower risk forms of prostate cancer that are unlikely to be lethal.

  5. It is never quite clear to me in these studies whether adopting such habits long before being diagnosed with prostate cancer make it far less likely the cancer will be lethal … even if high risk. Or if it is intended as a prophylactic guideline against diagnosis … or a little of both?

    Like you, Mike, I am/have been for many years a “6” and it didn’t stop me getting diagnosed with high risk disease.

  6. Rick:

    I think the point is simpler than that. It is that good health habits are generally a very good thing. The recommendations being made would probably lower one’s risk for death for all sorts of things — from cancer to heart disease — prior to one’s inevitable death from old age. Arguably, the fact that I did all of these things may have prevented me from actually dying of my heart attack and having what appears to be a very high quality recovery. However, doing these things is not a guarantee of anything. There is simply a series of very strong associations between healthy living and longer, healthier life. Similarly, there are a series of strong associations between not spending a lot of time in war zones and a longer, healthier life!

  7. Hi Mike (responding to your comment of November 30, 2015 at 12:08 pm)

    Just two thoughts here. You mentioned your “attempts to eat less fats than normal”. The line of thought and research I have followed for years is that it’s not a “low fat” diet that is healthy, rather it is a diet low in saturated fat. There is a mound of research suggesting that. The flip side is that a diet low in all fat appears to be somewhat unhealthy.

    The second point is about tomato intake, which Sitemaster has already commented on. While raw tomatoes are okay, our digestive systems tend not to break down the natural capsules containing the lycopene — a key element considered beneficial, so much of it passes right through us. Processing (such as mashing) or cooking does break down the capsules, making the lycopene much more bio-available.

    This brings back memories. After being diagnosed with a life-threatening case back in late 1999, my wife and I soon learned that lycopene and tomatoes were likely helpful to us in combating prostate cancer. For the next year my wife virtually insisted I consume a 12 ounce can of stewed tomatoes at every dinner! Sitemaster mentioned that exercise can get boring, but you can take it from me that 12 ounces of tomatoes at every dinner really gets old fast. That said, I’m still here and going strong, and the tomatoes are probably part of my success. I now do it the easy way: two servings of V8 juice a day gives me 14 servings of lycopene a week, and that’s on top of tomatoes in salads, in occasional pasta sauce, ketchup (Nixon was right!), etc.

  8. Thanks for Reporting This

    This gets repetitive, but hearty thanks once again for posting this encouraging research! This is a good study for us advocates/educators to take to health fairs.

  9. I was diagnosed 2 years ago at age 51 — PSA of 254, Gleason scores of 8-10, and enlarged lymph nodes extending up the torso (sorry, don’t recall the exact name — they didn’t call them tumors, though). The only good news was that the cancer wasn’t in the bones.

    No surgery, but Lupron shots and 9 weeks of radiation. I also elected to change my diet from the typical American diet (high in Big Macs) to one that is practically sugar free and vegan (although I eat salmon two to four times a week). I decided to make the switch after watching “Forks over Knives” and doing some research on prostate cancer and vegan diets.

    I quit smoking 25 years ago, and pretty much work out three times a week at the gym (along with a bowflex at home).

    Current status: PSA undetectable, off Lupron, testosterone levels normal, and all the swollen lymph nodes have “resolved”. Keeping my fingers crossed that it stays that way, but living by Breaker Morant’s famous line, “Live every day as if it’s your last, for one day, you’re sure to be right.”

    It was nice to see this study. (I scored the max.)


  10. Thanks everybody for your interesting insights. Just a few more thoughts on what I was saying before.

    From the age of 33 (now 72), I have had my PSA and DRE done yearly, plus a very active lifestyle, proper weight, and good diet; no smoking and practically no alcohol at all. All tests were negative, then about 8 years ago, out of the blue, I found I had full-blown prostate cancer. The specialist told me it was too far gone for a prostatectomy, what a shock to both of us! As I explained before, it was T3N0M0 with Gleason 8 histology, and a PSA of 7.5. Invasion of the seminal vesicles was the main reason for the high “score”.

    We (my wife and I) were of the opinion that I might be one of the lucky ones and get the average 5 years of life. I had 24 sessions of EBRT, then the specialist told me they were in a position to give me my first choice which had been high-dose brachytherapy (via template installed in the perineal area) over a 24-hour period of intermittent treatment. So the remainder of the EBRT was cancelled and we went ahead with the new treatment. I was the first patient in the country (Ireland) to get this done.

    Before, during, and after the foregoing, I was being given ADT (Prostap3). The PSA dropped to “normal” and so it has continued to this day. The ADT was stopped after about 18 months. There was no history of prostate cancer in the family. So, what I suppose I am saying is this: You can be as careful and as well informed as is possible, but there is no certainty that you won’t get this illness.

    The lesson is, I think, to get tested from a reasonably early age and be constantly vigilant. I know that the majority of males I converse with do not know what a PSA is, and certainly do not have annual medicals. I’d better cut this short or I’ll be censored for long-windedness! Wishing you all well for the future.

    PS: I forgot to mention that I am totally impotent since all this happened, but I have learned to live with that aspect. As they say in my country “a little life is sweet”.

  11. 5 years?

    Hi Mike,

    I’m thinking your bad luck happened because you did not imbibe enough or any Guinness, but I have had no enrolled medical education and might be wrong about that.

    I’m curious but have a hunch about this statement of yours: “We (my wife and I) were of the opinion that I might be one of the lucky ones and get the average 5 years of life.” About 16 years ago that was suggested to me too by two well-respected doctors treating prostate cancer, and I have heard it from many others with challenging cases in the US, especially some years ago. Fortunately, even then, many of their doctors had not kept up with the latest figures and developments, especially outside surgery. In short, their doctors were wrong, and I’m thinking your source may have been reading the same music. In sharp contrast, in the US at least, survival at 10 years is 99% and is 94% at 15 years, and that averages in all patients, including those with widespread metastases at diagnosis! The group that pulls down the average is men with distant metastases at diagnosis, only 28% of whom make it to 5 years (though even those men are almost certainly doing better today as the figures were likely based on a period ending several years ago, before the slew of new and powerful drugs for men with late-stage prostate cancer). In contrast, men with regional spread beyond the prostate have a survival rate of “nearly 100%” at 5 years.

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