Colon Lessons from a Prostate Study? …Yup!

Do you remember the Prostate, Lung, Colorectal, and Ovarian Cancer Screening trial (also now known as “PLCO”)? It was a very famous U.S. study, paid for by U.S. taxpayers, that tried to determine the importance (pros and cons) of a variety of common cancer screenings, and it enrolled over 154,000 men and women aged 55-74 years from the early 1990s to 2001. New research from PLCO looked at over 17,000 participants who received a baseline flexible sigmoidoscopy for colon cancer screening, who were then again rescreened years later.¹

On the day of their first/baseline screening, the participants of this specific study I am mentioning today had one thing in common –  “clean” sigmoidoscopy with no precancerous polyps! Yeah! “Celebrate Good Times Come On” (sorry, but that was one of my favorite dance songs in high school). Okay, so let us cut to the colonoscopy (aka “chase”), or sigmoidoscopy in this case, when it was performed years later in this study among this select group of initially sans-polyp men and women, and why it was such an amazing finding. This study became one of the first prospective evaluations to look at the impact of weight loss or weight gain and what happens to the distal (latter part of intestines) colon. It appeared there was a significantly reduced risk of precancerous colon polyps (adenomas, which can lead to colon cancer) with weight loss over time, and weight gain was associated with an increased risk for these colon polyps, with a stronger impact the earlier the weight changes happened in life. In other words, it is never too early to try and achieve some healthy weight/waist loss or try and discourage some unhealthy weight/waist gain.  These findings, if accurate, are remarkable because they translated to a 46% reduced risk of distal colorectal polyps with weight loss of just 2 pounds per decade for those that are in the overweight or obese category. Also, gaining weight of approximately 6 pounds or more every 5 years was associated with a 30% increased risk of precancerous growths or adenomas. The average age of the participants in this part of the study was 62 years old. Interestingly, these polyp and weight associations were stronger in men compared to women who were overweight or obese.

Why is Moyad talking colon health? Good question! The PLCO trial received so much initial and overwhelming attention on the topic of PSA screening that it unfortunately did not receive the attention it also deserved in terms of lifestyle changes. Some of the more interesting lifestyle advice has come from this so-called “PSA study.” For example, we now know the importance of discouraging unhealthy weight gain when it comes to prostate enlargement or cancer, but who knew that good colon health tips could also come from this study? There is evidence all around us that lifestyle changes can make a “Head-to-Colon” difference (ahh that was a clever one that I just thought about) and some of the best evidence comes from studies that do not get enough credit because the headlines are dominated by other themes from those exact same studies. The take home message is as clear as an intestinal tract with no polyps (sorry but I cannot help myself) – when you improve your overall health, it has an ability to also improve other countless and more specific areas of your body health. Healthy weight loss when needed is colon healthy? Yup! Prostate healthy? Yup! Heart healthy? Yup! Brain healthy? Yup!  Kidney healthy? Yup! Liver or Pancreas healthy? Yup! Yup! Important for overall sexual health? Yup! Will it keep your kids from no longer wanting to borrow your car or from asking for money? Nope! Sorry, but there are some things healthy weight loss cannot do … unfortunately. Yup!

References: 

1. He S, et al. JNCI Cancer Spectrum 2022; https://doi.org/10.1093/jncics/pkab098