Thursday, August 05, 2010

An interesting documentary

I watched the most interesting documentary today on Rogers On Demand. It was a talk given about the effectiveness of cancer screening in the general population.

People tend to think that if cancer is found earlier, it can be treated earlier and the person will live longer. So we screen to find early-stage cancers and treat any that are found. The thing is, while people are living longer with their cancer, statistically they aren't living any longer than they would have if their cancer had been found when it showed symptoms. People whose cancers are found using early screening techniques are living the same length of time as if they'd never been screened at all.

The person giving the talk discusses why this is true and the biases that are part of this thinking, as well as some of the harm that general screening actually does. People think of general screening as helping but statistically, it's not actually helping at all. And yet when organizations suggest changing the screening guidelines to not screen everyone, people howl. We all want out mammograms and PSA tests no matter what because we've been conditioned to think that more screening is better.

I think that someday, more screening will be better but that this is not true right now. At the moment, scientists don't really understand how cancer works. They know how a bit about how it grows but they don't know which cancerous cells will mutate back into non-cancerous cells, or which cancerous cells are never going to spread away from the site. So they treat everything that they find whether the treatment is actually needed or not, causing some people to be overtreated. Overtreating cancer might possibly be better than waiting and watching or not treating it... but if the treatment doesn't affect how long the person lives, is it actually better? I don't know.

This talk definitely gave me a lot of food for thought and I recommend it. It can be a bit dry at times but it's still interesting. if you don't have Rogers On Demand or don't want to access the service, you can find the talk online here.


Unknown said...

Chantelle, what was the documentary called? I'm going to try to find it though we don't have Rogers in Qc...

Chantelle said...

It's just called "Cancer Screening" on the On Demand service. At the Research Channel link at the end of the post, you can download the video or watch it in Quicktime or Windows player.

The research channel link also says that the talk is by Barnett Kramer, director of the Office of Medical Applications of Research at the NIH in the US.