Peter Attia weighs in on colonoscopies and colon cancer screening tests.
Verdict: A colonoscopy is superior
And I agree. I’d probably be dead without them.
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This is a new treatment for Colon cancer just released by Eli Lilly - Fruquintinib. It’s an incremental improvement of survival for colon cancer patients but unfortunately not earth-shattering.
Better to get screened and not develop colon cancer in the first place.
http://www.hutch-med.com/elunate-fruquintinib-hong-kong-hospital-authority-drug-formulary-enlistment/
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- Stress and working at night are both known to affect cancer risk, including colorectal cancer risk.
- Colorectal cancer risk and progression have both been linked to the microbiome, dysregulation of which has been linked to stress and disruption of the circadian rhythm.
- Recent research in mice has linked stress and a disrupted circadian cycle to disruption of the gut microbiome, and suggested that this may contribute to colorectal cancer progression due to its impact on intestinal permeability and inflammation.
These were the findings of a study in mouse models of colorectal cancer, which appeared in Science Advances in September 2024.
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Neo
#169
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This would seem to be the nail in the coffin for the carnivore diet:
Now, researchers from the National Cancer Center Singapore (NCCS), together with scientists from Singapore’s Agency for Science, Technology and Research (A*STAR), have identified the mechanism linking the excessive consumption of red meat to colorectal cancer.
Worldwide, colorectal cancer, which affects the large intestine or rectum, is the third most common cancer, accounting for around 10% of cancer cases. It’s also the second leading cause of cancer-related deaths. In addition to age and family history, lifestyle factors such as diet, inactivity, obesity, smoking, and excess alcohol consumption can increase the risk of this type of cancer.
Using fresh colorectal cancer samples, the researchers discovered that the iron in red meat reactivated the enzyme telomerase via an iron-sensing protein called Pirin, which drove the progression of the cancer.
Paper:
Over-consumption of iron-rich red meat and hereditary or genetic iron overload are associated with an increased risk of colorectal carcinogenesis, yet the mechanistic basis of how metal-mediated signaling leads to oncogenesis remains enigmatic. Using fresh colorectal cancer samples we identify Pirin, an iron sensor, that overcomes a rate-limiting step in oncogenesis, by reactivating the dormant human telomerase reverse transcriptase (hTERT) subunit of the telomerase holoenzyme in an iron-(Fe3+)-dependent manner and thereby drives colorectal cancers. Chemical genetic screens combined with isothermal dose-response fingerprinting and mass spectrometry identified a small molecule SP2509 that specifically inhibits Pirin-mediated hTERT reactivation in colorectal cancers by competing with iron-(Fe3+) binding. Our findings, first to document how metal ions reactivate telomerase, provide a molecular mechanism for the well-known association between red meat and increased incidence of colorectal cancers. Small molecules like SP2509 represent a novel modality to target telomerase that acts as a driver of 90% of human cancers and is yet to be targeted in clinic. Significance: We show how iron-(Fe3+) in collusion with genetic factors reactivates telomerase, providing a molecular mechanism for the association between iron overload and increased incidence of colorectal cancers. Although no enzymatic inhibitors of telomerase have entered the clinic, we identify SP2509, a small molecule that targets telomerase reactivation and function in colorectal cancers.
Full Paper (open access)
相关：
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tj_long
#171
Chicken and turkey meat don’t seem to be as harmful, apparently due to their lower iron content?
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RPS
#172
This headline suggests only the iron in red meat is the issue but not iron from vegetables like spinach, sweet potato or broccoli.
Of course that is totally misleading.
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tj_long
#173
Heme iron vs non-heme iron.
RPS
#174
That wasn’t clear from the New Atlas article.
But I’ll stand corrected if that is the real reason.
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I haven’t read the paper yet, but even if its not making the distinction between heme iron / non-heme iron, the density is such that it would seem most vegetarians would likely get a far lower dose than a carnivore diet aficionado…
and for comparison, Salmon:
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RPS
#176
I guess it all depends on how well one absorbs iron.
Although I’m not on a carnivore diet I do eat a huge amount of red meat and yet my iron levels remain too low for me to be able to donate blood.
Maybe that’s why my recent colonoscopy showed no hint of a single polyp.
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That brings up an interesting question - is it the consumption of iron, or the amount in the blood. I would think you are right, that its the blood level that would matter. But perhaps once its in tissues, that is when it does the damage in the prostate / colon, etc.?
It would seem that its doing the damage even before its reaching the bloodstream, in this case, as its increasing the telomerase in the lining of the colon where the meat is passing through. Or - perhaps I’m wrong on this; any experts want to chime in?
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Neo
#181
Interesting - are they saying blood test < colonoscopy but stool based test same order of magnitude as colonoscopy?
Comparing effectiveness
Ladabaum and his collaborators collected previously published data on six commercially available or in-development blood- and stool-based screening tests as well as the gold-standard colonoscopy. Using this data, they modeled the relative rate of colorectal cancer and deaths among 100,000 average-risk people who used each screening approach.
Among 100,000 people who receive a colonoscopy every 10 years, 1,543 would develop colorectal cancer and 672 would die from the disease, they determined. For stool-based tests every one to three years (depending on test) the incidence of colorectal cancer ranged from 2,181 to 2,498 cases per 100,000 people, and deaths ranged from 904 to 1,025. For the new blood tests, recommended to be conducted every three years, the cases ranged from 4,310 to 4,365, and deaths ranged from 1,604 to 1,679 — about two and a half times as many deaths as in the colonoscopy group.
Among those who receive no screening, 7,470 would develop the cancer, and 3,624 would die from it.
Moreover, when the group looked at the costs associated with each test, they found that colonoscopies and stool-based tests were more cost-effective than the blood-based tests.
“The blood tests are certainly much better than nothing, but you’ll worsen the population outcomes and raise health care costs if you see people switching from colonoscopies to first-generation blood tests,” Ladabaum said.
Sadly, a Paywalled Paper:
https://www.acpjournals.org/doi/10.7326/ANNALS-24-00910
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Neo
#183
Wonder how much those stats improve for stool (and blood) if it really is every 12 months or even every six months compared to every 3 years?
—
Could see a compressive, holistic strategy being something like:
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colonoscopy every 10 years or so (depending on risks and past colonoscopy results)
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stool test once a year (and do it for other things too, for microbiome, etc at the same time to get most from the “logistics” at once)
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blood test (depending on how much cost be driven down) a few times in between as part of normal routine (biohacker) blood work
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