The healthcare industry is quite inefficient at allocating money to things that are needed and have a decent chance of working.
For example, in the field of oncology there's very little money put into cheap accurate early screening. And an almost obsessive pour of money into trying to understand mid-to-late stage cancers. Even James Watson has criticized this.
It's a sad situation, because we now know early pre-clinical tumours leave a trace of circulating DNA in blood. And it seems like a darn important and doable inference problem to distinguish cancer from control patients.
> For example, in the field of oncology there's very little money put into cheap accurate early screening. And an almost obsessive pour of money into trying to understand mid-to-late stage cancers. Even James Watson has criticized this.
I'm in no way an expert, but isn't part of that related to increasing evidence that early detection of a tumor isn't necessarily a benefit? I recall reading many tumors stop or grow so slowly that treating them has more of a downside than an upside. This is one of the reasons why early breast cancer screenings aren't a benefit.
You're definitely right that merely detecting tumors earlier doesn't always help, because many of them are relatively slow-growing and fairly harmless. But this actually makes a very specific kind of early detection research even more important: research to help us predict which early-stage tumors will progress to becoming deadly, and which ones won't. Currently we're pretty bad at making this prediction for many kinds of cancer, but if we could detect them all early AND distinguish the really bad ones from the mellower ones, we'd know exactly who to treat aggressively.
It depends on the type of cancer. For instance, a surprisingly large portion of the population likely has thyroid cancer and doesn't know it, and many have it and it isn't treated. It's a very slow-growing cancer usually, and just not worth bothering with until the tumor gets large enough to cause real problems due to its size (then they usually just cut out part of your thyroid, leaving the other part to continue working as normal, or at worst they cut out the whole thyroid and you have to take a Synthroid pill every day).
Other cancers, like pancreatic cancer, are very aggressive so the earlier you catch them the better.
I would think early screening would discriminate by type of cancer so you can see if you have something that needs immediate attention.
> a surprisingly large portion of the population likely has thyroid cancer and doesn't know it, and many have it and it isn't treated
A larger portion of the population has prostate cancer. You probably have it right now.
My mom likes to tell a story from one of her classes at medical school. The teacher had a bunch of slides of prostate material; you had to identify which prostate was cancerous. There were so many questions ("this one looks cancerous. Is this it?") from the class that he was forced to announce "look, there's a bit of cancer in everyone's prostate. Find the one with an obvious problem".
It's slow, but it will get you if nothing else does first. :/
> Uh, why didn't she teach the known diagnostic criteria?
Generally you would do this before having the lab in which students are expected to use the knowledge. It's kind of pointless the other way around. In other words, that doesn't help with the problem. Knowing the official diagnostic criteria is often not helpful for diagnosing a condition.
Your oncologist will be winging it based on their past experience.
> Prostate cancers are graded according to the Gleason system. This system assigns a Gleason grade based on how much the cancer looks like normal prostate tissue.
> If the cancer looks a lot like normal prostate tissue, a grade of 1 is assigned.
> If the cancer looks very abnormal, it is given a grade of 5.
> Grades 2 through 4 have features in between these extremes.
> Most cancers are grade 3 or higher, and grades 1 and 2 are not often used.
> The Gleason score can be between 2 and 10, but most are at least a 6. The higher the Gleason score, the more likely it is that the cancer will grow and spread quickly.
> Since prostate cancers often have areas with different grades, a grade is assigned to the 2 areas that make up most of the cancer. These 2 grades are added to yield the Gleason score (also called the Gleason sum).
Note that this explicitly contemplates, at the low end of the scale, that it's difficult to distinguish between normal prostate cells and cancerous prostate cells.
Grades 1 and 2 are not often used because biopsies, a fairly invasive process, tend to be taken from men who are already suspected to have higher-than-average levels of cancer. If we took biopsies from a representative population sample, grades 1 and 2 would feature prominently in the results. That is the point of the med school anecdote -- even in samples artifically chosen to highlight the difference between a normal prostate gland and one with a serious problem, you just can't keep low-grade cancers out of the "normal" samples.
The point of the lab exercise is to give students practice grading cancers, and recognizing the difference between serious prostate cancer and run-of-the-mill prostate cancer. Only experience will help with this, because the diagnostic criteria are "prostate cancer runs the full continuum".
It is the norm in medicine that a question of the form "does this patient have this condition" has no truly objective answer. Surgery is well understood; internal medicine is not.
From the article 'Instead of calling it “encapsulated follicular variant of papillary thyroid carcinoma,” they now call it “noninvasive follicular thyroid neoplasm with papillary-like nuclear features,” or NIFTP. The word “carcinoma” is gone.'.
Great link, thanks. This affects me directly: I had one of these thyroid nodules found recently, but they've decided it's small and nothing to worry much about, so they're just going to keep an eye on it.
From your link:
"At major medical centers, many patients with encapsulated thyroid tumors are already being treated less aggressively. But, thyroid experts say, that is not the norm in the rest of the country and the rest of the world."
I guess it's a good thing I was sent to a major medical center (one large enough where my oncologist specializes only in thyroids) or else I might be getting part of my thyroid cut out for no good reason now....
There is actually now a LOT of interest in the biomedical community for circulating tumor DNA - a quick Pubmed search yields 3317 results and Illumina is practically throwing money at the field. You have to keep in mind that the sequencing technology has only recently become cheap and sophisticated enough for this kind of highly sensitive testing to be possible.
Maybe it's doable. Early screening methods like mammograms have huge problems with false positives. Early screening has to be extremely accurate to overcome the false positive problem for low base rate events. That's hard.
I'd reckon that part of this is related to how "easy" it is to get a drug approved for certain-death cancers. The barrier for a drug's approval is lower if the alternative is a certainty of painful death. This is sort of changing as we now seem to have plenty of those kinds of therapies, and the new goal is much more precise targeting of cancers (immunooncology is one example).
For example, in the field of oncology there's very little money put into cheap accurate early screening. And an almost obsessive pour of money into trying to understand mid-to-late stage cancers. Even James Watson has criticized this.
It's a sad situation, because we now know early pre-clinical tumours leave a trace of circulating DNA in blood. And it seems like a darn important and doable inference problem to distinguish cancer from control patients.