To Have or to Not Have…
…a colonoscopy for colorectal screening.
Colonoscopy is considered the gold standard for colon cancer screening. Until recently there were NO randomized controlled trials (RCTs) examining the benefits of colonoscopy screening on colorectal cancer death or all-cause mortality. The Nordic-European Initiative on Colorectal Cancer (NordICC) (linked here) is the first RCT that examined the benefit of colonoscopy on colorectal cancer and all-cause mortality.
This study has been quite controversial - some believe it proves colonoscopy is an excellent screening tool and others believe the study demonstrates that colonoscopy is of no benefit.
The NordICC trial had two groups:
1) those who were offered a colonoscopy (experimental group)
2) those who were not (control group).
The trial observed that if you actually get a colonoscopy your risk of death from colorectal cancer goes from 0.3% to 0.15%. That is a REALTIVE risk reduction of 50% (0.15% is 50 percent of 0.3%)and an ABSOLUTE risk reduction of only 0.15% (0.3% - 0.15% = 0.15%). Only 42% of people in the group that were offered a colonoscopy actually had the colonoscopy. If you look at that entire experimental group (those who had and did not have the colonoscopy in that group) there was NO REDUCTION in the risk of death from colorectal cancer or death from all-causes compared to the control group. This is likely because ONLY 42% of that group actually had the colonoscopy.
I interpret this study to mean that a screening colonoscopy can be good for an individual to prevent colon cancer, however, it is not a great population level screening tool as many will chose not to get the colonoscopy (in this study 58% of participants decided to not have the colonoscopy).
One big thing to highlight:
there were ZERO colon perforations (life threatening complication) in the 11,843 colonoscopies performed.
The perforation rate in US is is about 1 in 1400 based on the literature (see here).
I suspect we did not see any perforations in this study as the countries where the study was performed DO NOT use anesthesia for colonoscopies.
The US uses light anesthesia for colonoscopies
In theory it is way harder to perforate a persons colon who is awake compared to one who is asleep. A colon perforation is very painful and just prior to that occurring the patient would experience a lot of pain, so if you are awake you can voice your pain or kick the doctor.
In the end if you want to prevent colorectal cancer a colonoscopy can be a great tool, but it appears to not be a great population level tool, as many will decline it. If you have a colonoscopy consider doing it without anesthesia so you can decrease the risk of a colon perforation, the one rare but major risk of the procedure. Additionally, there are less invasive stool testing options for colorectal cancer screening, namely Cologuard and Fecal immunochemical test (FIT) testing.
If you want more on this topic here are two articles both written by doctors with opposing views on this topic. Positive view of the study. Negative view of the study.
