Since ‘early detection’ is a key factor in treatment, I am wondering if there is currently a test that will detect presence of cancerous cells in the body, no matter where they reside: lung, breast, testicles, stomach, skin, etc.
Wouldn’t it make sense to get a cancer test, say, every 6 months, or are they prohibitively expensive for the average individual/family?
Well a complete blood count or CBC is usually used in most blood work to detect whether your levels are low or not for [plasma? red/white blood count??] not sure really. But this is an indicator and I get tested every 6 months. I pay nothing for blood work - I’m mostly looking for cholesterol and other stuff but there is always a CBC done.
NOw I’ve heard of people getting a cbc and still having cancer. It’s not fool proof or even very accurate it’s just one measure people take. You could get a full body scan that I’m sure is not covered by insurance and see what happens there.
No, cancer is a really large catagory and not all cancerous cells act the same way. For PET/CT we use a radiolabled sugar molecule to look at growth rate. Some cancers grow faster than normal tissue, others slower, others just the same. Depending on what cancer they are looking for, the cancer will be shown in an overabundance or void of the radioactive sugar.
There are 250 cell types in your body, and each can turn cancerous. Every one of these is unique in its own way, like having different receptors on their surface. So I don’t think it’s possible to detect all 250 with a single screen, unless you’re looking at a certain area, then a pathologist could look at a sample and tell you if it is cancerous.
There is one protein - p53 - that mutates in 50% of all cancers. Maybe you could at least look for this, but seeing as how it is inside of cells it would be difficult.
I know you’re not suggesting a PET scan as a routine screening test, but the following is “quite interesting”. For a trial I’m involved with we had to declare what the radiological risk was to patients in the information packs we give to them prior to consenting them. Our radiological protection officer calculated that:
One PET scan is the equivalent of 600 chest x-rays and one CT is the equivalent of 400 chest x-rays.
I’m not a medical physicist, but I would hazard a guess that those are not exposures you would want unless they were absolutely necessary.
The reason cancers are usually better-treatable if found early is that they haven’t had a chance to spread yet: The cancerous cells are still restricted to one hopefully small part of the body, and so you can remove the tumor all at once, or sometimes that entire part of the body. If you can detect the cancerous cells anywhere else in the body, then it’s too late for the early treatment, since the cancer has already spread. You’d have to take samples from everywhere in the body, and if you take that too far, there isn’t any body left when you’re done sampling.
It is not so much the individual expense as it is the cumulative expense. A $10/person test is 3 Billion for all US citizens; it has to save $3B worth of health to be cost-effective.
In any case, the idea of “early detection” holds true only for a subset of cancers that tend to be solid masses before they metastasize or turn more malignant, and for certain conditions such as colon polyps that can be precursors to cancer.
The cost of screening is significant, and a sensitive enough screen even for solid tumors must have factored into its value the costs and risks of tracking down false positives.
In the not-so-distant future genetic markers may let us tailor who should be screened for what, but right now there is not “a” cancer test.
Not to mention the treatment of cancers that really don’t require it. Lots of elderly men have silent prostate cancer. It doesn’t cause symptoms and they die of other things, so it has absolutely no effect on them, but if they were told that they had cancer they’d want (and quite understandably imo) treatment.
Same goes for meningiomas (which are largely benign), they’re found in a significant percentage of elderly people at autopsy…they only really need treatment (which is rather expensive) if they cause symptoms, but who is going to be happy when they’re told that they have a brain tumour.
Well, hey, I spend all day doing molecular oncology testing. We offer a few dozen tests in our lab alone, just to narrow down diagnoses of different lymphomas and leukemias. Cancer diagnosis can be quite complex.