Keep on screening

livestrong by KaCey97007

Rethinking cancer screening?
[Via Respectful Insolence ]

ResearchBlogging.orgHere we go again.

I see that the kerfuffle over screening for cancer has erupted again to the point where it’s found its way out of the rarified air of specialty journals to general medical journals and hence into the mainstream press. This is something that seems to pop up every so often, much to the consternation of lay people and primary care doctors alike, often trumpeted with breathless headlines along the lines of “What if everything you knew about screening was wrong?

It isn’t, but some of it may be. The problem is the shaking out process. I’ll try to explain.

Over the last couple of weeks, articles have appeared in newspapers such as the New York Times and Chicago Tribune, radio networks like NPR, and magazines such as TIME Magazine pointing out that a “rethinking” of routine screening for breast and prostate cancer is under way. The articles bear titles such as A Rethink On Prostate and Breast Cancer Screening, Cancer Society, in Shift, Has Concerns on Screenings, Cancers Can Vanish Without Treatment, but How?, Seniors face conflicting advice on cancer tests: Benefit-risk questions lead some to call for age cutoffs, and Rethinking the benefits of breast and prostate cancer screening. These articles were inspired by an editorial published in JAMA last month by Laura Esserman, Yiwey Shieh, and Ian Thompson entitled, appropriately enough, Rethinking Screening for Breast Cancer and Prostate Cancer. The article was a review and analysis of recent studies about the benefits of screening for breast and prostate cancer in asymptomatic populations and concluded that the benefits of large scale screening programs for breast cancer and prostate cancer tend to be oversold and that they come at a higher price than is usually acknowledged.

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It is easy to read the headlines and think that screening does not work. It does but we also need to recognize that just doing more screening does not necessarily help if we do not really understand all the facets underlying the disease being screened for.
It turns out that a significant minority of breast cancers resolve on their own. We really do not have a good way of knowing which ones have to be treated now and which would resolve without treatment. Some cancers might be very slow growing and present a very small chance of mortality. But, again, we can not really tell the difference, so all get treated the same.
As the blog post states:

So what’s the solution? Should we give up on screening?

I’ll answer the second question with an emphatic absolutely not. There is no doubt that screening can save lives; the problem is that we’re doing it “bigger” and “badder” and not necessarily better or smarter, using more or less a one-size-fits-all approach when a more tailored approach might actually be necessary. Also, we’re using 20th century technology, when 21st century technology might be able to find a way out of these conundrums. Here’s where I (mostly) agree with Esserman et al. We need to change how we screen for common cancers using the latest advances in biochemistry, molecular biology, and technology to differentiate which lesions are most likely to be cancer and which are not, which cancers are likely to progress to the point of threatening a patient’s life in their remaining lifespan and which ones are not.

We need to improve our screening approaches by having a better understanding of all the biology involved, including the specific biology that an individual possesses. We will get there but it may be a little confusing until then.

The comet’s the thing

comet <i>by Charleston (South Carolina) County School District CAN DO Project.
it’s a comet! it’s a meteor! no, it’s a piece of rna!
[Via Research Blogging - Biology - English]

What do you get when you take pyrimidine molecules, freeze them in a vacuum to -340°F, then expose them to ultraviolet radiation you’d find in space? Think about it for a second. If you took a few extra credits in a college biology class, you may remember that your DNA contains purines and their chemical [...]…

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It is really interesting to read about organic chemistry that can take place in the vacuum of space, at such low temperatures and under UV irradiation at levels that should be very destructive to most complex molecules.

Yet, in this experiment, some very important biomolecules could be formed. The key seems to be the presence of water, which not only protects the molecules from UV but also permit the reactions to occur.

Perhaps Fred Hoyle’s panspermia hypothesis has some real validity for the appearance of Earth-bourne life.

Science is wonder-full (not a misspelling)

supernova 1994DbyNASA, ESA, The Hubble Key Project Team, and The High-Z Supernova Search Team
License to Wonder

[Via Olivia Judson]

Yes, science relies on facts, but also on speculation and inspiration.

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This is a really nice discussion regarding two, somewhat divergent aspects of doing scientific research. Most people are used to the inductive reasoning aspects of science – understanding the specific in order to understand the general.

An large part of science is made up of assembling the millions of small facts and data points into a cohesive understanding of the world around us. The answer is methodically arrived at by the slow accumulation of information.

But sometimes, and this is often where the wonder of science comes from, deductive reasoning takes precedence. Here we go from ‘general’ principles to the specific. We can make up an answer and see how well it fits the data.

In the example used by Judson, Watson and Crick took the general principles of chemistry to create a structure first, and then saw if it could explain the specific data from X-ray crystallography, while Franklin was trying to use the data only. With each wrong structure, they got closer to the right one.

In some ways it is a backwards way to go to get the accurate description of Nature. It can not always be used, as our imagination so often comes up with all sorts possibilities that are simply wrong. It requires scientists with very good understanding of general principles. And it usually requires extremely good data of the highest order to reveal Nature’s secrets in this fashion.

Watson and Crick had the internal knowledge to keep their conjectures within realistic bounds. And they had access to data no other speculator had. They ‘won’ the race because they had access to Franklin’s data while Linus Pauling did not. Thus their conjectures could be self-corrected in ways that no one else’s was.

Darwin is an example of someone who displayed both aspects of science in one tremendously important person. He collected data of the highest order. HIs understanding of the principles permitted him to see the general aspects of natural selection, which permitted him to gather even more data to support the specific ramifications of the theory.

Science often moves in contrapuntal cycles of inductive and deductive reasoning, traversing from specific to general to specific and so on, each cycle moving us closer to a fuller description of the world around us.

This is the fascinating wonder of science. To move from close-up to panorama and back again, each time gaining new knowledge of Nature.

Isaac Asimov said:

The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ (I found it!) but ‘That’s funny …’

But the real thrill to a scientist is when we can complete the ellipsis by stating. “Oh, so that’s how it works” as we get a little chill down our spine realizing that Nature is just so amazing! That is when science is just so full of wonder. (Thus my choice for a title.)