AnUser
#146
I wouldn’t be so sure about that. Atorvastatin has a lower incidence of diabetes compared to rosuvastatin, and if we speculate this could be off-target effects in muscles relating to HMGCR inhibition for the latter reducing the glucose sink.
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tananth
#147
I believe lipophilic Statins are better at penetrating the brain’s BBB, so would be better to control cancers in the brain. On the other hand, depleting cholesterol (particularly Desmosterol) in the brain can cause “brain fog”, which is less likely with non-lipophilic statins like rosuvastatin, though they still penetrate the BBB, just somewhat less. I would not use lipophilic statins just for brain cancer prevention if I had any symptoms of “brain fog”.
In the rest of the body there is probably no obvious difference between different statins in effect on intra-cellular cholesterol and hence no difference in effect on cancer prevention.
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AnUser
#148
If you can measure serum desmosterol that is correlated with brain desmosterol.
I don’t think there is any recent evidence establishing the claim that some statins penetrate the BBB differently, if you have any I’d like to take a look at it.
If you can’t measure serum desmosterol then you cna use other things than statins.
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tananth
#149
Bempepoic Acid also lowers intra-cellular cholesterol, but mainly in the liver since it is a pro-drug that requires a liver enzyme to be converted into the active form.
Ezetimibe just lowers LDL cholesterol in blood by blocking absorption from food, but all cells that need more cholesterol can absorb LDL cholesterol from the blood, and if internal cholesterol synthesis in cancer cells is shut down with Statin + Bempedoic Acid, cancer cells can still get cholesterol from LDL in the blood. However the additional benefit on top of Statin + Bempedoic Acid is probably small both for reducing LDL cholesterol and intra-cellular cholesterol in cancer cells.
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tananth
#150
I agree that there is little evidence that Rosuvastin is better than Atorvastin at not reducing desmosterol : I would not use any Statin if I had symptoms of brain fog, unless I actually had cancer. Fortunately most people only get brain fog for a few weeks after starting on high dose statins and the brain somehow adapts.
2 Likes
AnUser
#151
Do you have any evidence showing that brain desmosterol changes levels is related to possible brain fog side effect? The turnover for brain cholesterol is very long and most is synthesized early in life.
No it’s from cholesterol that’s dumped to be reabsorbed by the body.
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Neo
#152
Thanks for color
Not sure if in practice Bemp or Eze will lower cell cholesterol through the body than PCSK9i will
They seem to mostly impact the the blood levels
@AnUser outside of statins do you think the others would have a meaningful impact on cell levels (and hence potentially help prevent cancer)?
AnUser
#153
I don’t understand the question.
Neo
#154
Tananth said:
That roughly only seems to potentially be correct for statins
(A) do you think the effect of statins is likely to be material enough outside of the blood and through the bodies cells to have an impact on cancer?
(B) even if (A) is true, do you think one would expect Bempedoic Acid and Eze to have a similar effect? (I don’t because most of their effect is just via the blood, not what each cell does with its own cholesterol synthesis)
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AnUser
#155
I would recommend searching for clinical trials and see if whatever you searched for show potential for prevention.
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tananth
#156
According to the website I linked, Bempedoic Acid has an anti-cancer effect (as an ACLYL inhibitor), independent of its effect on cholesterol. Second BA further lowers LDL cholesterol (beyond what is achievable with Statins alone) which indirectly prevents cancer cells from getting much cholesterol from the blood. Finally, BA lowers intra-cellular cholesterol inside the liver, so would help with liver cancer, or metastatic liver lesions.
Ezetimibe only indirectly helps fight cancer by further lowering LDL cholesterol. Unfortunately, there is no way to eliminate all cholesterol in cancer cells, since there will always be some LDL cholesterol in the blood that cancer cells can draw on, but the lower the LDL cholesterol, the better.
5 Likes
Neo
#157
Thanks guys. Was interested in understanding the pathways and logic. Still not sure why PCSK9i should be less “ex ante” logical to help vs Ezetimibe. But no worries. Not need to spend more time on this for my sake.
tananth
#158
I am still taking PCSK9i (Praluent) + Ezitimibe, since I don’t like the “brain-fog” I was experiencing with Atorvastin. I plan to continue on Praluent, as long as I don’t have cancer, but might add a small dose (5mg per day or every other day) of Atorvastin to hedge my bets.
It is indeed unclear if PCSK9i actually have a net negative effect on cancer growth since the benefit of lower LDL cholesterol (leaving less for newly divided cancer cells to suck up) should roughly cancel the effect of higher intra-cellular cholesterol, if existing cancer cells are not gaining more intra-cellular cholesterol than other cells. Given that PCSK9i acts more strongly on liver cells than most other cells in the body, most LDL cholesterol should be removed by liver cells, so except for liver cancer PCSK9i might actually still provide a net protection again most cancer cells. And you might even end up with net protection against liver cancer if you combine Bempedoic Acid (which primarily lowers cholesterol production in liver cells) with PCSK9i, which might be a good strategy for those intolerant to Statins.
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On the statin chemoprevention question: I have not made a thorough review of the literature, but from a bit of a dig there is evidence that statins improve survival in patients with existing cancers of various kinds, including colon, prostate, breast, and lung — so not just the liver. But it’s quite inconsistent and of variable methodological quality. Here is a summary of previous studies by an observational study that did find a protective effect against colon cancer:
Few epidemiologic studies have investigated the effect of statin use after diagnosis on cancer-specific mortality in patients with colorectal cancer. Although our main finding (fully adjusted HR, 0.71; 95% CI, 0.61 to 0.84) is consistent with a Scottish study of 308 patients with colorectal cancer, which observed a nonsignificant 58% reduction in colorectal cancer-specific mortality in statin users after diagnosis (HR, 0.42; 95% CI, 0.17 to 1.05),9 their findings may be subject to immortal time bias.16 This bias occurs because individuals who survive longer are more likely to receive a medication and, consequently, the medication erroneously seems protective.16 Lakha et al9 used Cox regression models and therefore, to account for immortal time bias, medication use should be investigated with time-varying covariates,16 but this is not mentioned. Our main finding is consistent with a recent American study by Mace et al10 of 407 patients with rectal cancer who were undergoing chemoradiotherapy, which observed a marked but nonsignificant reduction in cancer-specific mortality in patients using statins both before and after surgery (HR, 0.62; 95% CI, 0.32 to 1.18). Finally, another American study by Ng et al11 used observational data from a trial investigating chemotherapy regimens (statin use was not randomly assigned) and found no association between statin use and cancer recurrence (adjusted HR, 1.14; 95% CI, 0.77 to 1.69). Although there is some overlap in the CIs from our study and in the study by Ng et al,11 inconsistency in the estimates could reflect the different methodologies used.
https://ascopubs.org/doi/10.1200/JCO.2013.54.4569
Regardless, the key thing seems to be the intracellular cholesterol synthesis pathway, and in particular two intermediates (geranylgeranyl pyrophosphate and farnesyl pyrophosphate) that stimulate Ras and related oncogenic pathways. So non-statin drug classes (except maybe Bemp in the liver) aren’t going to do it, if there is a real ‘it’ to do.
And there’s next to nothing in primary prevention, this (in a very high-risk group) being one of the few.
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Atorvastatin failed to prevent cancer deaths in the ITP though perhaps combining it with either acarbose or a SGLT2 inhibitor could yield slightly higher lifespan extension than either by themselves.
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Ludovic
#162
Great post, I found this case report of a hepatocellular carcinoma interesting when I did some research on cyproheptadine;
tananth
#163
Good catch about the anticancer mechanism of statins being related to Geranylgeraniol(GG): I was considering supplementing with statin plus GG (a precursor of CoQ10), but that would completely eliminate the primary anti cancer mechanism of statins!
Hopefully, just using CoQ10 with statin will still preserve the anti-cancer benefit.
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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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