I haven't read those books but I've seen other studies claiming the same thing; they were flawed and not to be relied on.

In my own case - if I hadn't been screened for cancer I'd probably be dead within 10 years. Instead, I probably won't be. Cancer screening saved my life.

To Carmella S:

If you know of any studies that show that screening for any type of cancer produces a clinically significant reduction in mortality, I'd love to take a look at them.

You always have to start with the null hypothesis. The burden of proof always rests on anyone who proposes any kind of medical intervention. Since there is always the possibiity of iatrogenic illness, anything the medical profession does that does not have clear benefits should be considered harmful. As the article makes clear, a diagnosis of cancer can ruin your life.

You say, "If I hadn't been screened for cancer I'd probably be dead within 10 years. " What is you basis for saying that? Many small cancers disappear of their own accord, or don't grow, or grow so slowly that they never cause any harm. Even if you had one that was harmful, how do you know that you wouldn't have done just as well had you waited until sympotoms appeared?

I'm not arguing with you, I'm just trying to separate the signal from the noise. If you have any data that could shed light on these matters, I'd like to take a look at it.

Sorry but CarmellaS is all noise no signal. She didn't even have the decency to drop your thought provoking blog a thumb. I wouldn't be surprised if the whole thing was a con. I bet the medical industry pockets loads of cash while ruining those earl detection patient's lives. monkey fingered.

I'm happy to discuss this with you Patrick, I too don't feel like we're arguing. The first thing I should point out is that I'm totally speaking as a layperson (though I've had training in statistics) and unfortunately don't have time right now to do any research on the issue, even though it's interesting. I can tell you though about my own case.

I understand about the null hypothesis and the possibility (actually probability, at least on a short-term basis) of developing iatrogenic problems from cancer treatment. In my own case, even though of course I can't say for sure that I'd be dead in ten years, a statistical program said that my long-term prospect for survival was about 30% without treatment. It was a very 'high-grade' (corelated with agressiveness) form of cancer that was fortunately found early at the miscoscopic stage. A microscopic amount was also found in my lymph nodes. The prevailing theory is that the fact it was found in my lymph nodes meant that it was spreading through my bloodstream and that, if unchecked, would metasticize (sp.) elsewhere. There is another theory, which is that the fact it was found in my lymph nodes meant that they (the nodes) were doing their job of 'catching' cancer cells before they spread throughout the body. You would think that you would be able to tell if there were in fact microscopic cancer cells bloating around one's bloodstream, but apparently attempts to do so haven't been reliably predictive.

I did extensive research before I was treated and did find a school of thought that believed that I shouldn't be treated, although this was very much the minority view. My own feeling was that, while it was possible that my cancer would just go away on its own, no one could be sure of that - it was just a guess (as, admittedly, is the theory that it would surely spread). I then had to balance the 'costs' of cancer treatment versus the benefits.

The benefit of undergoing treatment was that it could greatly extend my life, possibly up to four decades. It's an unproven benefit, but I figured that since no one knew for sure, I'd give it a 50% chance of it occurring (possibly a little high, as even extensive treatment wasn't sure to be successful).

The cost of cancer treatment - realistically, about two years of my life (including surgery, chemo, radiation, and recovery time). The possibility of the treatment killing me was about 2% (it would be higher, but I got bonus points for being younger and otherwise healthy). I also balanced the possible long-term cognitive effects (chemobrain) and a small (less than 1%) risk of long-term heart damage.

In the end, I decided that I would rather go through treatment that take the risk of dying of cancer by age 50. Waiting for symptoms to appear didn't seem to be a good option, because by the time they appeared the cancer would probably have metasticized (sp. again) and it would be too late to do anything.

I realize that my decision was based on the statistical program being correct as to my survival odds without treatment. I did some reading on how the program was created, of course it was done on the basis of studies, and the reliability of some of the studies is limited because most people with cancer are going to have treatment for it. But unfortunately that's all we have to go on.

I know this is long and doesn't fully answer all of your questions, but like the studies it's the best I can do at the moment. The real question, to me at least, is 'how reliable are the studies' and 'can we make them more reliable'. The answer, in my case at least, is that the reliability is by no means certain but it's all we have, and there's no real way to make it more reliable because again, most people diagnosed with cancer, even very early-stage cancer, are going to choose treatment.

Also affecting my decision was the fact that some of the drugs I was taking, which had only become widely available in the past few years, had reliable been shown to reduce death rates (albiet in people whose cancer was more advanced than mine). So I knew that the drugs I was taking were effective, even if it wasn't 100% certain that I actually would need them. But the only way to find out if I truly needed them was to wait 10 years and see if I were dead, and I wasn't willing to take that chance.

Anyway, sorry for the long comment and I hope this was helpful. I guess the point for me is, that whether or not screening is 'worth it' from a societal standpoint ($ expended versus lives saved), it can be worthwhile from an individual standpoint. (again, even if I can't 'prove' that screening saved my life, it can't be shown that it didn't, and given the odds I'd rather have the chance to try to beat away death for another 40 years than to not have that chance).

Okay, thanks to both of you for your comments.

It all depends on what type of cancer.

Screening for cervical cancer is very effective and saves thousands of lives. The best part is that the screening can reveal pre-cancer. Pre-cancer is easily treated (simple office procedure) and then the cancer never develops.

Screening for prostate cancer, on the other hand, is much more problematic. The screening test has a very high false positive rate, meaning that lost of people have biopsies that never needed them. Even when early stage cancer is diagnosed, it is not clear that treating it aggressively is very beneficial, since most prostate cancers will never kill the patient.

Each screening test for each cancer must be judged on its own merits.

Dr. Amy:

Thanks for your comment.

I know that it was recently revealed that the five-year survival rate for prostate cancer in the US was 90%, while in the UK it was only 40%. This led to a whole lot of hand-wringing and breast-beating in the UK, until somebody pointed out that the death rate due to prostate cancer was exactly the same in both countries, which means that there must be a whole lot of men in the US who are diagnosed with and treated for prostate cancers that never would have bothered them in their lifetimes.

If you know of any studies on the efficacy of screening for cervical cancer, I'd appreciate it if you could pass them on.

This is important issue that doesn't get talked about enough, although I've noticed the NYT has been doing some articles on the hard data in the past few years and I applaud them for that. Whenever I hear people trumpet that early screening saves lives, I hesitate to raise the contradictions as they usually are discomfited.

That said, here's a simple point to consider: If you die of cancer in 2015 and your cancer was detected in 2008, then you are considered a long term survivor of cancer and a success of early detection. But if you die in 2015 and your cancer was detected in 2012, you aren't. Either way, you're dead in 2015. From this simple change in detection date, stats of how early detection saves lives are born. But the outcome is the same.

And then there's the issue of what effects cancer treatment itself has, which is esp compelling because they know now that cancers vary hugely in lethality and some don't even need to be treated. Chemo and rad and other treatments are tough on the human body. They can lead to or even cause other cancers, heart attacks and strokes. So they may hasten death or at least not postpone it. But because they are not directly linked to the cancer, someone who dies of one of those causes (e.g. heart attack) is not considered to have died of that cancer, and is thus another success story. One difference would be to track deaths from all causes in people who've had or been treated for cancer, but that's still not done, to my knowledge.

These are just two of the most compelling arguments against the current state of both cancer detection and treatment if you care to search and look for them. But I find most people are really freaked out by questioning the conventional med argument that cancer detection and treatment is an unmitigated good.

To Silkstone:

You wrote: "I find most people are really freaked out by questioning the conventional med argument that cancer detection and treatment is an unmitigated good."

Yes, exactly.For most people, medicine has become the modern-day substtitute for religion. And like true believers of all stripes, they really hate it when anyone asks them for EVIDENCE to back up their beliefs.

I have done much research on the question of mammograms and have decided not to have them regularly. I have a very low risk profile; no one in my huge extended family has had breast cancer. You cannot imagine the grief I have gotten from physicians on this subject. I have even been told to find a different doctor if I refuse to comply.

To Mary King:

That's amazing.

But you're probably better off without that jerk of a doctor, anyway.