Over screening for cancer is nothing short of a national disaster.

PSA tests and mammograms have created a generation of men and women battling the lifelong side effects of devastating treatments they didn’t need because the cancers never would have hurt them in the first place.

But there’s one screening that’s different — a screening that can detect a deadly cancer and remove it at the same time.

And if you’re like most people, it’s the very one you’ve been avoiding: the colonoscopy.

Now, a landmark new study in the New England Journal of Medicine shows why you shouldn’t be avoiding yours. In fact, these findings may have you calling your doctor today to schedule it — because data on 2,602 patients tracked for 15 years finds that colonoscopies can slash your risk of dying of colon cancer by 53 percent.

But despite the fact that colonoscopies save lives, only half of the people who should get scoped actually do.

It’s not hard to see why. A colonoscopy sounds about as pleasant as…well…a colonoscopy.

In reality, it’s not nearly as bad as you’d think.

Thanks to the anesthesia, you won’t feel a thing during the procedure itself. The worst part is actually the night before, when you’ll have to take a preparation that’ll empty your bowels.

All I can say is, get a good book and stay close to a toilet.

To make it easier on you, schedule your colonoscopy for first thing in the morning. Since you can’t eat until the procedure is done, you won’t spend the day hungry — and you won’t spend the day stressing over it, either.

But that’s not the only reason you want to be the early bird on this one: Several studies have shown that doctors detect more polyps early in the day than they do in the afternoon.

Finally, some doctors offer a less-thorough version of the colonoscopy called the sigmoidoscopy. Others will try to get you to pay extra for a “virtual” colonoscopy.

Both of them may be tempting. They both might sound a little more comfortable and a little less invasive.

Don’t fall for it. When it comes to colon screenings, nothing beats the real thing: A genuine colonoscopy by a competent doctor.

If you’re past 50 and haven’t had one or are overdue for your next one, no more excuses. Pick up the phone and schedule yours today.

Exploitation — it’s the only word that comes to mind here.

Even as the mainstream moves away from routine cancer screenings for men and women alike, there’s one group of Americans that are still getting screened regularly for cancers that almost certainly won’t hurt them.

And that’s the elderly.

These are the people least likely to need treatment even if a cancer is detected — and least able to withstand the traumatic surgeries, dangerous drugs, and toxic chemotherapy often used to “treat” those cancers.

But the numbers don’t lie — and the newest numbers show that 57 percent of men between the ages of 75 and 79 were screened for prostate cancer, while 42 percent of men older than 80 were actually given PSA tests.

You have to wonder what the doctors are thinking here: They know these cancers can take decades to develop, decades an 80-year-old doesn’t have. They know that even younger men have nothing to worry about in most cases. They know that the U.S. Preventive Services Task Force recently recommended doing away with the PSA test altogether.

They know all this… yet they’re screening anyway, and not just men.

The same study in the Archives of Internal Medicine found that 62 percent of women between the ages of 75 and 79, and 50 percent of women older than 80 have been given mammograms over the past two years.

And if PSA exams are useless for men, mammograms are every bit as useless for women — so useless that even mainstream docs are backing away from them.

That’s because all the mammograms in the world have barely made a dent in the breast cancer death rate. These screenings have succeeded in finding harmless cancers, which then end up being treated with disfiguring surgeries and dangerous radiation.

Similarly, the study also found that 53 percent of women between 75 and 79 and 38 percent of those older than 80 were given pap smears to test for cervical cancer.

It’s ridiculous — and even the mainstream groups that normally back most cancer screenings agree. The American College of Obstetricians and Gynecologists recommends ending pap smears as early as 65, while the American Cancer Society says there’s no benefit after the age of 70.

In reality, many of these screenings have no benefit at any age. But for seniors, many of whom are already fighting health issues, these screenings, biopsies, and inevitable cancer treatments can turn the golden years into a living nightmare.

Skip ‘em — because in this case, what you don’t know almost certainly won’t hurt you.

You might think medical guidelines are based on years of clinical evidence and gold-standard research. After all, doctors use them every single day to make life-or-death decisions.

In reality, they’re based on the whims and fancies of the medical elite… and that’s especially true when it comes to women’s health.

A new study finds that nearly a third of 717 practice recommendations issued by the American College of Obstetricians and Gynecologists are based solely on expert opinions — with another 38 percent driven by the kind of weak observational studies I’m always warning you to take with a grain of salt.

All told, just 30 percent of the guidelines obediently followed by 50,000+ ACOG doctors are based on gold-standard clinical trials.

That’s it.

In other words, there’s not a lot of “evidence” in the “evidence-based medicine” touted by the mainstream. But it does help answer some of the questions I’ve had about ACOG.

This is, after all, the same group that issued a defiant new call for more frequent mammograms — despite solid evidence that those screenings have led to the mass overtreatment of benign tumors. (Read about that here.)

Those guidelines have punished a generation of women with disfiguring mastectomies and toxic radiation — but as I’ve told you before, they’ve barely made a dent in the breast cancer death rate. (Read the story here.)

ACOG isn’t the only group issuing guidelines despite a lack of clinical evidence to back them up: One study earlier this year found that six out of seven guidelines issued by the Infectious Diseases Society of America had no solid research behind them.

That’s why docs were told to pump patients full of antibiotics the moment they even suspected pneumonia in a patient — a practice that fueled the overuse of the meds and helped breed drug-resistant superbugs… without actually improving outcomes.

And in even more outrageous cases, guidelines are written under the watchful eye of “experts” with a direct financial stake in the outcome — like many of those issued by the American Heart Association and American College of Cardiology between 2003 and 2008. (Read about it here.)

Put it all together, and the sad reality is that the deck is stacked against you before you even set foot in the doctor’s office — and that’s why whenever your doctor gives you a treatment, you need to stop and ask him why before you follow his orders.

I’ll have more on the questions you need to ask during any trip to a doctor later this week.

A new spin on mammograms has managed to take a badly flawed technology… and make it even worse.

Imagine that!

The technology is called computer-aided detection, or CAD, and it’s supposed to help radiologists find potential cancers in breast tissue — which would be great if it actually worked.

In reality, all it seems good for is giving women a good scare. That’s because this “advanced technology” is great at detecting “abnormalities” — but not so great at detecting actual cancer.

If you want proof, take a look at the data from a study published in Journal of the National Cancer Institute. Researchers looked at data on 1.6 million mammograms given over an eight-year span. They found that even though CAD revealed more “abnormalities,” the rate of invasive breast cancers that were detected remained the same — whether CAD was used or not.

Clinics with CAD also had a lower rate of accurate diagnoses of “abnormal” mammograms than clinics without the technology.

And, for the cherry on top, clinics with CAD had a higher rate of false positives — which meant that more women had to undergo additional tests, when none of it would have been necessary to begin with.

The same team carried out a similar study in 2007 with similar results — so if anything, CAD is consistent.

Consistently bad.

Despite that lousy track record, CAD is now widely used. If you’ve had a mammogram recently, chances are your own radiologist used CAD.

The obvious answer is for radiologists to give CAD the boot. But even if they did, there’s a bigger picture to keep in mind.

CAD or no CAD, mammograms are dangerously overused and wildly inaccurate — and they’ve led to the mass overtreatment of a disease that won’t hurt most women.

The radiation used in mammograms alone can cause the very cancers they’re supposed to detect. Even mainstream mammogram backers will be forced to admit it if you ask them directly (expect some hems and haws first, though).

Instead of tweaking this failed screening, it’s time to scrap it altogether and find one that really works instead.