How does that help you test for early stage cancer markers? That tests usually isn't in the batch of regular (and it's quite expensive), but it does make a difference between death an survival.
Yeah, pancreatic cancer patient here. Mine presented as acid reflux, which my GP treated with Prilosec. Only after I went anemic and the ER staff scanned for a bleeder did they find the 8-9 cm tumor. Push your GP if necessary for some soft-tissue radiology if you feel "not right". Wish I'd caught mine a couple months earlier.
(Six months after surgery - I'm well so far, still doing chemo for the next three months. We'll see, we'll see.)
Glad you are doing well. Pancreatic cancer is probably the scariest of all cancers, and I can hardly imagine your ordeal.
Still, one needs to be careful about taking one incident and generalizing from that. There is, for example, a very real possibility that performing an ionizing-radiation scan for every patient who presented with acid reflux would cause more cancer than it cured.
It's the saying doctors learn in medical school. "When you hear hooves, think horses not zebras."
Probably 99 out of 100 people with GP's symptoms (if not more) actually do have acid reflux. It therefore makes medical sense to assume that until additional symptoms indicate a different conclusion.
The general issue is that doing more tests can catch more things earlier. But all tests have false positives, and false positives can lead to more tests and in some cases to unneeded treatment, which can cause more harm than good.
It's perhaps unintuitive, but more testing isn't always good. The benefits need to outweigh the risks, and it isn't always the case. There are ongoing debates about who should be screened for various types of cancer, for example, and the "right" answer changes over time - as we find ways to reduce false positives, as we find better treatments, as we better understand the diseases, etc.
It's tempting to do more tests because it feels like you're doing something. You don't want to get sick later and feel like you could have prevented that. But that's an irrational form of thinking. All that we can do is make the best choice now, given our current information. As GP's links mention, the best choice we have now often seems like "avoid tests that aren't clearly needed."
The assumption that "it does make a difference between death an survival" in not necessarily born out by the data.
There has been a big push back recently against using an improvement in 5 year survival rate as an indication of success in the war on cancer. For example, if a new diagnostic test lets you find out you have cancer earlier, but you still end up dying at the same age you would anyway, the 5 year survival rate would go up, with no real benefit to you. In fact, there could be lots of real negatives, like anxiety and an increase in other tests and procedures that don't actually improve your lifespan or quality of life.
I'm not sure I understand your point - are you arguing that finding cancer earlier does not increases chances of treatment and survival? Do you have any reliable data on that?
The conclusion:
"Although 5-year survival is a valid measure for comparing cancer therapies in a randomized trial, our analysis shows that changes in 5-year survival over time bear little relationship to changes in cancer mortality. Instead, they appear primarily related to changing patterns of diagnosis."
When I had cancer I just wanted it gone. Since it could be cut out, I went with that. Every time I caught a cold I worried that it had returned. I did not want to be on the wrong side of a statistical curve. That others survived would not have comforted me as much as knowing that I would survive. Your mileage may vary.
And how does testing for early stage cancer markers help you? It's not a rhetorical question, clinical studies have been unable to show the positive effect that you assume (and actually these tests may do more harm than good).
As per my previous post, a CEA blood test would have shown mine two orders of magnitude higher than normal. Further non invasive tests would have found my tumor, possibly before it metastasized. Or maybe not. But for the cost of my chemo, you could do 100 CT scans. (And I have to have one every two months.)
Your CEA levels were two orders of magnitude higher than normal at a point were it was sufficiently advanced to be diagnosed from symptoms (as it fortunately happened in your case). If you want to diagnose early, you need a much lower threshold and the CEA test is not good enough. It's not like people have not been trying to find screening protocols...
> In screening for colorectal cancer, the aim should be to detect disease at either Dukes’ A or B stage. Malignancy detected at more advanced stages is unlikely to be more treatable than that detected through the usual course of events. Using an upper limit of normal of 2.5 μg/L, Fletcher (19) calculated that CEA has a sensitivity of 36% and a specificity of 87% in screening for Dukes’ A and B colorectal cancer. These findings, combined with the low prevalence of this malignancy in unselected populations, render the positive predictive value of CEA unacceptably low and thus of little value in screening healthy subjects. For the present, therefore, we must rely on fecal occult blood and endoscopy to screen for colorectal cancer (20).
What does 36% sensitivity and 87% specificity mean? Imagine that you test ten thousand 40-year olds and twenty-five of them do actually have colon cancer (this is more or less consistent with statistics telling that 0.23 of them will be diagnosed with colon cancer before turning 50). You will get a true positive result in 9 cases (out of 25) and a false positive in 1297 (out of 9975). So only 0.7% of the positive cases are real, and you missed two thirds of the cancers.
