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COLORECTAL CANCER SCREENING


nicholson

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http://www.nejm.org/doi/full/10.1056/NEJMoa1300720#t=article

 

This well done research does not Show any reduction in mortality from colorectal screening and suggest low risk people may be increasing their odds of mortality

 

To be clear, this study does show a reduction in mortality from colorectal cancer: the issue is that it doesn't reduce total mortality.  See more on this here. Certainly, however, the question is more open for low-risk people: "Screening of men 60 to 69 years old had a strong effect on colorectal-cancer mortality; the relative risk of death from colorectal cancer was 0.46 (95% CI, 0.30 to 0.72) in the annual-screening group, 0.42 (95% CI, 0.27 to 0.66) in the biennial-screening group, and 0.44 (95% CI, 0.30 to 0.64) in the combined screening groups. ... No benefit from screening was observed for women less than 60 years old in the annual-screening, biennial-screening, or combined groups [RR in annual screening 1.01, 95% CI, 0.61-1.66; for women 60-69, 0.68 (95% CI, 0.46-1.01; for women ≥70, 0.42, 95% CI, 0.21-0.85 — Table 3).

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http://www.nejm.org/doi/full/10.1056/NEJMoa1300720#t=article

This well done research does not Show any reduction in mortality from colorectal screening and suggest low risk people may be increasing their odds of mortality

To be clear, this study does show a reduction in mortality from colorectal cancer: the issue is that it doesn't reduce total mortality. See more on this here. Certainly, however, the question is more open for low-risk people: "Screening of men 60 to 69 years old had a strong effect on colorectal-cancer mortality; the relative risk of death from colorectal cancer was 0.46 (95% CI, 0.30 to 0.72) in the annual-screening group, 0.42 (95% CI, 0.27 to 0.66) in the biennial-screening group, and 0.44 (95% CI, 0.30 to 0.64) in the combined screening groups. ... No benefit from screening was observed for women less than 60 years old in the annual-screening, biennial-screening, or combined groups [RR in annual screening 1.01, 95% CI, 0.61-1.66; for women 60-69, 0.68 (95% CI, 0.46-1.01; for women ≥70, 0.42, 95% CI, 0.21-0.85 — Table 3

 

Micheal, Of course it lowers colon cancer mortality. The big question being raised in simply:

Does colorectal cancer screening lower overall mortality. The best answer based on research is NO.

 

That leads us to ask if overall the mortality rates are equivalent then it appears likely that something negative is occurring due to the whole screening process and what it may lead to. Similiar to prostrate screening perhaps? IAC, if something is going on here it is likely that the screening for colorectal cancer in low risk individuals would be detrimental overall by raising mortality rates among those individual who get screened as opposed to those who don't.

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Mike,

 

"Does colorectal cancer screening lower overall mortality" was not the big question. Procedures are used to reduce the incidence of and mortality from colon cancer. That the dilution of colon cancer death by other causes results in the association of screening with all-cause death becoming not significant does not detract from the benefit. And, if I were able to chose my cause of death, colon cancer with not be among my top choices. And given my druthers between undergoing colonoscopy and suffering the agony and indignity of colon cancer treatment, even if it did or did not kill me, bring on the scope.

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http://www.nejm.org/doi/full/10.1056/NEJMoa1300720#t=article

This well done research does not Show any reduction in mortality from colorectal screening and suggest low risk people may be increasing their odds of mortality

To be clear, this study does show a reduction in mortality from colorectal cancer: the issue is that it doesn't reduce total mortality. See more on this here.  [...]

Micheal, Of course it lowers colon cancer mortality. The big question being raised in simply:

Does colorectal cancer screening lower overall mortality. The best answer based on research is NO.

I understand that, Mike: see the link I helpfully provided ;)xyz .

 

That leads us to ask if overall the mortality rates are equivalent then it appears likely that something negative is occurring due to the whole screening process and what it may lead to. 

 

... a reasonable hypothesis, which I don't think is correct, for reasons I gave in the link I helpfully provided.

 

Mike, we often get into these kinds of discussions. When I say something and direct readers to a link, please review it before replying.

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Also, there's no analogy between colonoscopy and prostrate screening.  The value of prostrate screening is dubious -- it's unclear whether prostrate screening has a significant benefit in preventing death from prostrate cancer -- but there is no question about the value of colonoscopy: it does  reduce the probability of death from colon cancer.

 

Also, don't settle for a "virtual colonoscopy" -- if you have e.g. polyps in your colon, a real colonoscopy will enable the gastroenterologist to remove them painlessly and effortlessly, as part of the procedure --  not so for a "virtual colonoscopy"  --  which possibly might also not spot some (if there any) of the polyps.  (Not to mention other precancerous growths.)

 

By the way, I've had two colonoscopies,one in my sixties, and one more recently -- both done by extremely competent gastroenterologist.

 

Happily, both colonoscopies showed perfectly healthy colons.

 

Result of CR?  Eating good foods?

 

:)xyz 

 

  --  Saul 

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Thank you Michael but I would ask you a simple question to keep it simple being as you have bothered to go to the trouble to consider this. Do you still consider colorectal screening to be worthwhile?

 

Yes. Unlike some other screening procedures, it's clear that it actually does reduce mortality from colorectal cancer; I see no plausible route from screening to increased mortality from other causes; and there's a plausible explanation for it reducing colorectal cancer mortality without detectably lowering total mortality and without elevating mortality from other causes.

 

I caution again, however, that people should carefully consider what kind of colorectal cancer screening they undergo, with the risks associated with colonoscopy being greater and the payoff smaller for people on CR than the general population. See here and here.

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Hi Michael!

 

While it is probably true that most CRronnies have a lower risk of colon cancer than the general population (better than average diet, and lower risk of cancers in general), it remains true that if a human (ad lib or CRON) develops precancerous polyps, a colonoscopy might save hir life. 

 

When I had my first colonoscopy, the gastroenteroligist first attempted performing the procedure with no pain killer -- I found that uncomfortable, so he applied a minimal amount of pain medicine.  The procedure proceeded comfortably. 

 

I had no constipation afterwards (I react strongly and negatively to pain killers -- during my shoulder operation, I was given vicodin -- which left me constipated for two days) -- a further indication of how little pain killer was used.

 

The bottom line:  If you're over 50 (or over 40 with a family history of colon cancer), get a REAL colonoscopy -- no matter how certain you are that CR will make you less cancer prone (which is probably true).

 

And my strong advice is to thoroughly check the reputation of the gastroenterologist that you arrange to perform the procedure.

Statistics have little meaning when dealing with a minor procedure like a colonoscopy -- the reputation of the physician performing the procedure is far more meaningful.

 

  --  Saul

It's not a m

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Hi Saul, Ive had two colonosopies one at 50 and one at 56. I hate them because I dont respond to the laxative. Its like drinking water. The last time I went two days on no solid food, drinking water and white grape juice and he still had to clean me out even though he gave me what he said was a more potent laxative. I refused the anithesia the second time though, and I have to say it was no big deal pain wise.

I am going to follow Micheal Rae's advice and go with the sigmoid and yearly fit test. I like his reasoning!

 

Thank you Micheal Rae

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OK Mike.

 

I had little trouble cleaning out my insides prior to my first colonoscopy; my wife is a nurse practitioner, specializing in gastroenterology, so I was in very good hands.  :)xyz

 

I'm impressed that you got away with no anesthesia; I tried using nothing the first time, at the recommendation of the gastroenterologist, but found that uncomfortable; so a mild antipain med was used.  That worked fine.

 

The second colonoscopy was performed at Rochester General Hospital, where my wife works, by one of the best gastroenterologist there; he gave me a mild anesthetic, and the next thing I knew (actually, a very few minutes later), the procedure was over.

 

Do what you want; if you've had polyps (I didn't), I wouldn't agree with Michael; during a colonoscopy, the gastroenterologist can easily, and will, painlessly remove them.

 

You can't do that with virtual procedures (also, most decent insurance will pay for a colonoscopy, but possibly not for alternate procedures).

 

Good luck,

 

  --  Saul

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Hi Saul and thanks for your feedback,

 

No polyps were found. As far as pain is concerned I hate it of course but if its short duration I am willing to put up with it. I once read that anesthetics have similiar effects on our brains as mild concussions. If thats true I would rather put up with 20 minutes of discomfort.

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  • 4 weeks later...

http://search.proquest.com/openview/fbc00565c506c7a8710b8d6bdb73266f/1?pq-origsite=gscholar&cbl=2043523

 

This recent review appears to contradict Michael Rae's confidence in the harmlessness of colon cancer screening.

 

Thank you Michael but I would ask you a simple question to keep it simple being as you have bothered to go to the trouble to consider this. Do you still consider colorectal screening to be worthwhile?

 

Yes. Unlike some other screening procedures, it's clear that it actually does reduce mortality from colorectal cancer; I see no plausible route from screening to increased mortality from other causes; and there's a plausible explanation for it reducing colorectal cancer mortality without detectably lowering total mortality and without elevating mortality from other causes.

 

I caution again, however, that people should carefully consider what kind of colorectal cancer screening they undergo, with the risks associated with colonoscopy being greater and the payoff smaller for people on CR than the general population.

 

See this recent review. They indicate that yes it is plausible that screening for colon cancer would have downsides that increase mortality and offset the lives saved by it. Michael sees no plausibility; I am not do sure especially considering that hospitals are the third leading cause of death!

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I caution again, however, that people should carefully consider what kind of colorectal cancer screening they undergo, with the risks associated with colonoscopy being greater and the payoff smaller for people on CR than the general population. See here and here.

 

 

http://search.proquest.com/openview/fbc00565c506c7a8710b8d6bdb73266f/1?pq-origsite=gscholar&cbl=2043523

 

This recent review appears to contradict Michael Rae's confidence in the harmlessness of colon cancer screening.

 

Thank you Michael but I would ask you a simple question to keep it simple being as you have bothered to go to the trouble to consider this. Do you still consider colorectal screening to be worthwhile?

 

See this recent review. They indicate that yes it is plausible that screening for colon cancer would have downsides that increase mortality and offset the lives saved by it. Michael sees no plausibility; I am not so sure especially considering that hospitals are the third leading cause of death! Downstream effects of screening may not just be a factor with prostrate cancer.

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"I’m skeptical about … screening colonoscopies"

 

Robert Clare, MD

http://robertclaremd.com/im-skeptical-about-screening-colonoscopies/
(emphasis added)

[...] here’s how the math works out: screen 100,000 asymptomatic people to find between 40 to 45 cancers, most of which will be early-stage with a decent chance for cure. That’s the good news. Now here’s the bad news; to save those 30 to 35 people (not every person diagnosed will survive), the test will harm upwards of 250 people, meaning that for every 1 patient who benefits, between 7 and 8 will be harmed. What kind of harm am I talking about? Diarrhea and dehydration from the bowel prep before; colon perforation, anesthesia reactions, and the occasional heart attack during; and GI bleeding and pain afterward.

 

Of the people suffering these complications, a few will have heart attacks and die, a couple will suffer fatal anesthesia reactions, some will develop congestive heart failure, a couple will die from hemorrhage, and a few more from peritonitis complicating a perforated colon. In fact, you are more likely to have your colon perforated from the test than you are to have a cancer diagnosed by it.

 

All told, you can expect 30 deaths per 100,000 colonoscopies performed, meaning that the death rate from colonoscopy is roughly equal to the number of cancer deaths averted through early detection. This is the dirty secret that the American Cancer Society never tells you when it advises that everybody undergo a screening colonoscopy starting at age 50.

 

Here’s why I’m not ready to throw in the towel on routine colonoscopy screening: As opposed to most other cancer screening tests, colonoscopy has the ability not only to detect cancer earlier than it might be otherwise, but also to prevent cancer before it occurs. You see, colonoscopy—which refers to the insertion of a fiberoptic scope up the rectum into the large intestine after a thorough bowel prep to rid the colon of stool—is also the best test for detecting polyps, small growths that can occur along the lining of the bowel. Polyps are exceedingly common, occurring in more than a quarter of people by age 50, and the reason they’re important to know about is that a small percentage of them will turn cancerous over time. The process is slow, typically a decade or more, which explains why a person with a “clean” colonoscopy at age 50, doesn’t routinely need another one for 10 years. In almost all cases polyps can be resected directly through the colonoscope. It is estimated that widespread screening colonoscopy and polypectomy (polyp removal) has the potential to prevent 65% of all colon cancers. The downside to this approach is that most polyps will never become cancerous and close surveillance in those with polyps inevitably leads to more screenings, more colonoscopies, more expense, more anxiety, and more bleeding complications.

 

How good are the [other ]tests? According to a Cochrane collaborative review, sigmoidoscopy versus no screening lowered colorectal cancer mortality by 28%, while stool screening for blood versus no screening reduced mortality by 14%. Compare this to the 40 to 50% reduction in the incidence of colorectal cancer associated with either daily aspirin or exercise, however, and it becomes clear that prevention through a healthy lifestyle is much more effective than expensive screening tests.

 

But if the real point of screening a population for disease is to increase the life expectancy of the group as a whole then colon cancer screening fails

 

A more difficult, ultimately unanswerable question is: how much would the risks associated with colonoscopies be reduced by following  Saul's sage advice: "choose a gastroenterologist with an excellent reputation before scheduling."

 

Cf. "Colonoscopy: A Gold Standard to Refuse"

https://www.drmcdougall.com/misc/2010nl/aug/colon.htm

 

"The Pros and Cons of Colonoscopies"

http://articles.mercola.com/sites/articles/archive/2015/12/09/colonoscopy-pros-cons.aspx

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Excellent post Sibiriak, Saul's point is good but also consider that all these studies are done on people in the general population. I think it is quite reasonable to assume that most CR people who do not smoke, drink booze, or eat red meat, bacon etc and eschew fibre, fruit and vegetables are at lower risk which means then looking at all the data we have it is Even less likely to benefit cr folks overall. In fact it may very well be a risk factor for them indeed

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Excellent post Sibiriak, Saul's point is good but also consider that all these studies are done on people in the general population. I think it is quite reasonable to assume that most CR people who do not smoke, drink booze, or eat red meat, bacon etc and eschew fibre, fruit and vegetables are at lower risk which means then looking at all the data we have it is NOT LIKELY A BENEFIT TO SCREEN CR folks overall. In fact it may very well be a risk factor for them indeed.

 

I would challenge Michael Rae to dispute that based on the evidence.

 

I discussed all of these in my original posts, to which I've already directed you. Note that the harms identified in the Robert Clare article all relate to colonoscopy: this, and the likelihood that CR folk are at lower risk of colon cancer (on the one hand) and at increased risk from colonoscopy-associated complications (on the other) is why I have personally concluded that FIT testing (which reduces cancer mortality as much or more than old-school fecal occult blood testing, with lower risk of false positives) is likely a better risk:benefit in People Like Me.

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Michael I think you are missing my point. A fit test as you reccomend has a high rate of false positives because it tests for blood which could be the result of other very common factors than colon cancer. That false positive would lead to a colonoscopy and as you have said risks that likely outweigh benefits for CR folks.

 

"How good are the tests? According to a Cochrane collaborative review, sigmoidoscopy versus no screening lowered colorectal cancer mortality by 28%, while stool screening for blood versus no screening reduced mortality by 14%. Compare this to the 40 to 50% reduction in the incidence of colorectal cancer associated with either daily aspirin or exercise, however, and it becomes clear that prevention through a healthy lifestyle is much more effective than expensive screening tests.

 

But if the real point of screening a population for disease is to increase the life expectancy of the group as a whole then colon cancer screening fails. Despite what you might have heard from Katie Couric (who had her colonoscopy broadcast on the Today Show in 2000 to promote colon cancer awareness after her husband died of the disease), your family doctor, gastroenterologist, and the American Cancer Society, colon cancer screening hasn’t saved any lives. Life expectancy and all-cause mortality in people undergoing screening are the same as in people who don’t. The small reduction in colon cancer death is simply replaced by a slight increase in death due to other causes like infection, heart attack, stroke, and other forms of cancer. There is no long term survival benefit to screening. One possible explanation for this is that chemo and radiation are toxic forms of treatment that increase the risk of dying from other causes. Another is that bodies are designed to fail, if not from cancer then from something else.

 

Results from the Minnesota Colon Cancer Control Study, a 46,551 patient cohort followed for 30 years. Colorectal cancer mortality and all-cause mortality with and without screening for fecal occult blood (see reference 5).

Results from the Minnesota Colon Cancer Control Study, a 46,551 patient cohort followed for 30 years. Colorectal cancer mortality and all-cause mortality with and without screening for fecal occult blood (see reference 5). Despite a reduction in colorectal cancer deaths, overall mortality was unchanged with screening."

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Michael I think you are missing my point. A fit test as you reccomend has a high rate of false positives because it tests for blood which could be the result of other very common factors than colon cancer. That false positive would lead to a colonoscopy and as you have said risks that likely outweigh benefits for CR folks.

There is a vast difference in raisk:benefit between a followup colonoscopy for diagnosis and removal, vs. the use of colonoscopy as a screening tool.

 

"How good are the tests? According to a Cochrane collaborative review, sigmoidoscopy versus no screening lowered colorectal cancer mortality by 28%, while stool screening for blood versus no screening reduced mortality by 14%. Compare this to the 40 to 50% reduction in the incidence of colorectal cancer associated with either daily aspirin or exercise, however, and it becomes clear that prevention through a healthy lifestyle is much more effective than expensive screening tests.

That is, of course, a false dichotomy. One takes a daily aspirin or exercises to prevent colorectal cancer; one screens for it to avoid dying from it if one develops it.

 

But if the real point of screening a population for disease is to increase the life expectancy of the group as a whole then colon cancer screening fails.  ...

 

Results from the Minnesota Colon Cancer Control Study, a 46,551 patient cohort followed for 30 years. Colorectal cancer mortality and all-cause mortality with and without screening for fecal occult blood (see reference 5). Despite a reduction in colorectal cancer deaths, overall mortality was unchanged with screening."

See my previously-posted analysis of the MCCCS ...

 

Come on, Mike: read what I post before arguing with me.

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mikecollela:  Life expectancy and all-cause mortality in people undergoing screening are the same as in people who don’t.

 

Perhaps a less important point, but still significant:

 

Robert Clare: As opposed to most other cancer screening tests, colonoscopy has the ability not only to detect cancer earlier than it might be otherwise, but also to prevent cancer before it occurs.

 

There is a big difference between surviving colon cancer (enduring various procedures and treatments) and never having colon cancer at all.    A reduction in cancer occurrence would itself be a positive outcome to take  into consideration.

 

But if the real point of screening a population for disease is to increase the life expectancy of the group as a whole then colon cancer screening fails.

 

A lot can be done to improve colon cancer screening.    On the social level,  that should be a key objective.

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Hi All!

 

Sibiriak correctly notes:

 

Robert Clare: As opposed to most other cancer screening testscolonoscopy has the ability not only to detect cancer earlier than it might be otherwise, but also to prevent cancer before it occurs.

 

 Also, I think that two many of us may have too much faith in the ability of CRON to protect our health -- yes, it IS a big plus -- but you should still exercise, get a colonoscopy and so forth -- to maximize your chances of a long healthspan and lifespan.

 

Concerning colonoscopy: to reduce the likelihood of surgical error, get a GOOD GASTROENTEROLOGIST to perform the procedure -- similarly for any other minor, or major, surgical procedure.  As (I think) Mike noted above, that's not something that shows up in the statistics.  

 

  --  Saul

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Hi All!

 

 

 

Also, I think that two many of us may have too much faith in the ability of CRON to protect our health -- yes, it IS a big plus -- but you should still exercise, get a colonoscopy and so forth -- to maximize your chances of a long healthspan and lifespan.

 

Concerning colonoscopy: to reduce the likelihood of surgical error, get a GOOD GASTROENTEROLOGIST to perform the procedure -- similarly for any other minor, or major, surgical procedure. As (I think) Mike noted above, that's not something that shows up in the statistics.

 

-- Saul

Saul I think based on the statistics it is reasonable to conclude that low risk people will not benefit from screening. Medicine is also a very major risk factor.

 

And Michael yes I did read your reference to the MCCC in the NEJM and considering the poor statistics I still maintain that LOW RISK people may be putting themselves in harms way with all these medical interventions.

Hi All!

 

 

 

Also, I think that two many of us may have too much faith in the ability of CRON to protect our health -- yes, it IS a big plus -- but you should still exercise, get a colonoscopy and so forth -- to maximize your chances of a long healthspan and lifespan.

 

Concerning colonoscopy: to reduce the likelihood of surgical error, get a GOOD GASTROENTEROLOGIST to perform the procedure -- similarly for any other minor, or major, surgical procedure. As (I think) Mike noted above, that's not something that shows up in the statistics.

 

-- Saul

Saul I think based on the statistics it is reasonable to conclude that low risk people will not benefit from screening. Medicine is also a very major risk factor. And Michael I did read your NEJM/MCCC reference. See below if you did not look at it in my previous post.

 

http://www.bmj.com/content/352/bmj.h6080/rapid-responses

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  • 1 month later...

 

Excellent post Sibiriak, Saul's point is good but also consider that all these studies are done on people in the general population. I think it is quite reasonable to assume that most CR people who do not smoke, drink booze, or eat red meat, bacon etc and eschew fibre, fruit and vegetables are at lower risk which means then looking at all the data we have it is NOT LIKELY A BENEFIT TO SCREEN CR folks overall. In fact it may very well be a risk factor for them indeed.

I would challenge Michael Rae to dispute that based on the evidence.

 

 

I discussed all of these in my original posts, to which I've already directed you. Note that the harms identified in the Robert Clare article all relate to colonoscopy: this, and the likelihood that CR folk are at lower risk of colon cancer (on the one hand) and at increased risk from colonoscopy-associated complications (on the other) is why I have personally concluded that FIT testing (which reduces cancer mortality as much or more than old-school fecal occult blood testing, with lower risk of false positives) is likely a better risk:benefit in People Like Me.

Well Michael the foBt has been reviewed by none other than Cochrane and they conclude no benefit wrt total mortality. The fit test has not been reviewed To my knowledge because its so new so you may be on to something. But if the foBt failed also to lower overall mortality in a random population which includes very high risk patients then I still remain suspicious of any screening for low risk individuals and it certainly cuts away at your rationale for fit testing especially in low risk populations considering the data is based on a population average which includes high and moderate risk individuals and NO mortality advantage.

 

An interesting read on the whole cancer screening dilemma is a book by H. Gilbert Welch, Less medicine more Health. Welch shows the data on why screening is often a bad choice for healthy people. He describes the sink hole of medical care people are often pulled into with screening for otherwise healthy people.

 

https://www.researchgate.net/publication/7319042_Does_Fecal_Occult_Blood_Testing_Really_Reduce_Mortality_A_Reanalysis_of_Systematic_Review_Data

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