Replies to post #143943 on Biotech Values

[DewDiligence]

The study was supposedly limited to colonoscopies rather than sigmoidoscopies.

[biomaven0]

Actually this was a US-based study. Here is the abstract:

Purpose
We designed this study to evaluate the association of colonoscopy with colorectal cancer (CRC)
death in the United States by site of CRC and endoscopist specialty.
Methods
We designed a case-control study using Surveillance, Epidemiology, and End Results (SEER)–
Medicare data. We identified patients (cases) diagnosed with CRC age 70 to 89 years from January
1998 through December 2002 who died as a result of CRC by 2007. We selected three matched
controls without cancer for each case. Controls were assigned a referent date (date of diagnosis of the
case). Colonoscopy performed from January 1991 through 6 months before the diagnosis/referent
date was our primary exposure. We compared exposure to colonoscopy in cases and controls by using
conditional logistic regression controlling for covariates, stratified by site of CRC. We determined
endoscopist specialty by linkage to the American Medical Association (AMA) Masterfile. We assessed
whether the association between colonoscopy and CRC death varied with endoscopist specialty.
Results
We identified 9,458 cases (3,963 proximal [41.9%], 4,685 distal [49.5%], and 810 unknown site
[8.6%]) and 27,641 controls. In all, 11.3% of cases and 23.7% of controls underwent colonoscopy
more than 6 months before diagnosis. Compared with controls, cases were less likely to have
undergone colonoscopy (odds ratio [OR], 0.40; 95% CI, 0.37 to 0.43); the association was stronger
for distal (OR, 0.24; 95% CI, 0.21 to 0.27) than proximal (OR, 0.58; 95% CI, 0.53 to 0.64) CRC. The
strength of the association varied with endoscopist specialty.
Conclusion
Colonoscopy is associated with a reduced risk of death from CRC, with the association
considerably and consistently stronger for distal versus proximal CRC. The overall association was
strongest if colonoscopy was performed by a gastroenterologist.
J Clin Oncol 30. © 2012 by American Society of Clinical Oncology

There are some weirdnesses in the data. GI docs showed no advantage in detecting the harder-to-detect proximal cancers compared with distal cancers (in other words they were better than PCP's by the same amount for both tumor locations). It may be that patients with PCP endoscopies were less educated or poorer than those who knew enough to use a GI doc.

Peter

[apljack]

Colonoscopy: This was some years ago, but my PCP ran a full colonscopy on me, unmedicated and had the machine turned around so I could watch the screen all the way to my cecum as he blew me up like a balloon! As I was virtually overwhelmed by the subjective "feeling" associated with an inflated colon, he would point out the minor AVM's and engage me in conversation. All I could remember was being glad that I knew that the "urge" was phantom, and the utter relief as he deflated me.

Several years later, I did a follow-up with a gastroenterologist who used verced. As I recovered from the aneasthetic, one of his partners tried to pigeon hole me about his mother-in-law, who had Fronto-temporal dementia and what he and his wife should do. I was too whacked out to tell him to F*&K off and make an appointment!

aj

[DewDiligence]

Overweight people more likely to have colon polyps, according to meta-analysis:

http://www.reuters.com/article/2012/07/12/us-colon-polyp-idUSBRE86B18Q20120712