The headlines have been jarring:

“Screening Procedure Fails to Prevent Colon Cancer Deaths in Large Study,” offered Bloomberg.

“In a Gold-Standard Trial, an Invitation to Colonoscopy Reduced Cancer Incidence but Not Death,” observed Statnews.

“Colonoscopy Fails to Reduce Rate of Cancer Deaths in Trial” volunteers realclearscience.com.

Have you heard about the 10-year follow-up of the large, multicenter, randomized Northern-European Initiative on Colorectal Cancer (NordICC) trial?

Researchers recruited healthy individuals in Poland, Norway, Sweden, and the Netherlands between 2009 and 2014. Most came from Poland (54,258), followed by Norway (26,411) and Sweden (3,646). The study authors did not include data from the Netherlands because of data protection law.

Should we ditch colon cancer screening?

Let’s get right to the recent report published in the New England Journal of Medicine:

The real-world risk of colorectal cancer and associated death rates appeared lower among people who had a single screening colonoscopy (compared with those not having the procedure), although only modestly so.

The researchers determined that the number needed to invite to undergo screening to prevent one case of colorectal cancer is 455. This number gives us an estimate of the effect of screening colonoscopy in the general population. Or does it?

The researchers determined outcomes based on intention-to-screen. In other words, they compared all subjects invited to have a colonoscopy screening with those who received no invitation or screening.

Here are some other study outcomes:

• The 10-year colorectal cancer risk was 0.98 percent for the screened individuals, compared with 1.2 percent for the unscreened subjects. While this 18 percent risk reduction sounds great, the absolute difference is small.
• The risk of death appeared similar in the invited group (0.28 percent) versus 0.31 percent in the usual care drop. Again, a nice relative drop (10 percent) but not particularly different in absolute numbers.
• The risk of death from any cause appeared similar in the invited and usual-care group members, at 11.03 percent and 11.04 percent, respectively.

My take — Colon cancer screening

The colonoscopy benefits would have been greater had more individuals had colorectal screening. Only 42 percent of those invited had a colonoscopy.

When the scientists adjusted for this low participation level, they discovered this:

Had all those invited to undergo screening had it, the 10-year risk of colorectal cancer would have dropped from 1.22 percent to 0.84 percent, and the risk of colorectal cancer–related death would have fallen from 0.30 percent to 0.15.

The NordICC is the first randomized trial to quantify the possible benefits of colonoscopy screening on the risk of colorectal cancer and related death.

Longer follow-up is needed to understand better whether colonoscopy is effective in this real-world analysis. Drs. Jason Dominitz and Douglas Robertson comment on the possible reasons for the low reduction in incident cancer and deaths observed in the NordICC study.

In an editorial that accompanied the study publication, they note that other studies suggest an approximate halving (40 to 69 percent) in the incidence of colorectal cancer and an up to seven-eighths (29 to 88 percent) decrease in the risk of death with colonoscopy.

We must take such observations in context: Historical non-randomized studies likely overestimate the real-world effectiveness of colonoscopy, given a lack of adjustment for incomplete adherence to testing. In addition, there is a tendency for healthier individuals to seek preventative care.

In the United States, colonoscopy is the main screening tool for colorectal cancer. In other places, participation rates may be quite different. In this sense, the real-world results in the USA may be closer to the results seen in the per-protocol analysis of this study.

I look forward to seeing if greater improvements in outcome emerge when the NordICC state has a 15-year follow-up. Finally, if the modest effectiveness of screening colonoscopy is real, can we afford to use this expensive screening tool? Or should we turn to less-invasive tactics such as FIT (fecal immunochemical testing)?

But Dr. Maas said that “around half of the patients in the study did not undergo colonoscopy, which may have negatively impacted the results. I will end with this observation about this study: Colonoscopy cannot possibly work if an individual does not have it. We need more evidence to guide us about the use of colonoscopy.

Thank you for joining me in the exploration of the effectiveness of colonoscopy.

The post Is Colonoscopy Effective? A New Study Raises Questions appeared first on Medika Life.

You may already know about the smell-sensing abilities of dogs. But dogs are not the champion in the sniffing arena. Smithsonian Magazine describes this animal as a walking dictionary of odors. Do you know to what animal it refers?

If you guessed the elephant, you are correct. Writing in Smithsonian Magazine, Paul Waggoner, associate director of the Canine Detection Research Institute at Auburn University, adds that rats and mice smell at least as well as dogs, and jackals are uncanny.

But for attitude? Your German shepherd prevails over those other animals. The problem? Training and keeping a detection dog is challenging and not cheap. Researchers are turning to mice, locusts, honeybees, and other animals in this context.

Cancer detection — Enter the ant

“Am I as admirable as that ant?”
― Nobuyuki Fukumoto, Saikyō Densetsu Kurosawa 11

Having been blessed to have studied with the late pioneer of evolutionary biology, E.O. Wilson, and his colleague Bert Hölldobler, I am fascinated with ants.

As a doctor specializing in cancer, you can imagine my delight at seeing this headline: “Cancer-sniffing ants prove as accurate as dogs in detecting disease.”

Scientists in France have shown they can rapidly train a specific ant species to detect cancer cells. Moreover, the accuracy of the insects is equivalent to that seen in other bio-detection heroes, including dogs.

The new study examines the ant species Formica fusca. Could these ants be trained? The researchers already knew that ants can home in on particular volatile organic compounds (VOCs) and that certain cancer types are identifiable by their unique VOCs.

Can these two observations be combined? In other words, can ants be trained to detect cancer cells?

In as few as three training trials, the ants learned to differentiate between cancer and non-cancer cells with an accuracy similar to that seen in dog studies.

The researchers concluded:

“Formica fusca ants can detect the VOCs emitted by cancer cells. A conditioning protocol based on only three training trials was sufficient for ants to associate cell-derived VOCs with a reward. Ants were able to i) perceive the presence of cells in a medium, ii) differentiate cancerous VOCs from non-cancerous ones, and iii) differentiate between two cancerous samples based on VOCs.”

The ants appear to be as good at detecting cancer as their canine counterparts. However, ants require only 30 minutes of training (over a training time of about three days), while dogs generally take 6 to 12 months.

Remarkably, the ants could distinguish between two different forms of breast cancer: The most favorable form (Luminal A)and a more aggressive one (“triple-negative”), respectively.

The researchers, referencing historical ant training investigations, believe that individual ants can be used to detect cancer cells up to nine times before their conditioned responses begin to wane.

This study is proof of concept, as numerous problems would need to be solved before ants can help detect cancer in the real world. Still, I am delighted that ants have demonstrated one more remarkable ability.

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