Dec
11
2009

Making sense of the recent cancer screening news

Breast x-ray
Breast x-rayCourtesy kristiewells
Lately, there’s been a lot of hoopla in the news about the over-screening of certain cancers, particularly breast and prostrate cancers. Back in October, an opinion piece published in the journal of the American Medical Association (JAMA) by researchers at the University of California, San Francisco and San Antonio’s University of Texas Health Science Center, called for rethinking in the screening guidelines for those two cancers. Although the researchers admit the regular screenings are beneficial, Laura Esserman, MD at UCSF says, “The benefit is not nearly as much as we hoped and comes at the cost of over diagnosis and over treatment.”

In a New York Times story about the report, Dr. Otis Brawley, chief medical officer of the American Cancer Society (ACS) is quoted saying “We don’t want people to panic, but I’m admitting that American medicine has over-promised when it comes to screening. The advantages to screening have been exaggerated.”

The report went on to say the ACS was “quietly working on a message, to put on its Web site early next year, to emphasize that screening for breast and prostate cancer and certain other cancers can come with a real risk of over treating many small cancers while missing cancers that are deadly.”

But the American Cancer Society responded with a claim that, despite the headlines, it wasn’t changing its guideline recommendations regarding screenings, and continued to stress that a mammogram was still “one of the best things a woman can do to protect her health.”

The story resurfaced again in late November when the United States Preventive Services Task Force issued new recommendations regarding breast cancer screenings, calling for postponing initial mammograms for women until the age of 50 rather than 40. The task force, a federal advisory board, made its decision to change the guidelines after reviewing evidence presented to it by a team of oncologists. The American Cancer Society opposes the new guidelines.

This whole story is somewhat confusing. And it’s that confusion that causes some in medical community to worry.

“I am concerned that the complex view of a changing landscape will be distilled by the public into yet another ‘screening does not work’ headline,” said Dr. Colin Begg a biostatistican at New York’s Memorial Sloan-Kettering Cancer Center. “The fact that population screening is no panacea does not mean that it is useless.”

On a recent post on the KevinMD blogsite, Dr. Amy Tuteur tries to unravel some of the confusion explaining why some medical experts think aggressive screening (and severe treatment) for breast and prostate cancer has done little to lower the death rate from these particular cancers. The PSA test, for instance, is utilized much more often in the United States than it is in the United Kingdom to screen for prostate cancer, yet the death rate from the cancer in each country is pretty much the same. It should be noted that for some cancers regular screenings are making a difference. Colon and cervical cancers are often treated successfully with early detection and by removal of cancerous or pre-cancerous tissue.

The problem is not all cancers behave the same way. Some can start small, grow slowly and if caught in the early stages, be treated (or removed) before they become fatal. And that’s been the classic cancer treatment paradigm for a long time. If all cancers behaved this way, aggressive screenings would be the way to go. But over the past decades doctors and researchers have learned a lot more about cancer biology. They now know certain cancers can erupt suddenly and explosively and become fatal very quickly. Others can appear and remain dormant - sometimes for years - and never become a problem during the lifetime of the patient. But because screening practices have become more agressive, more of the non-fatal tumors are being spotted and treated unnecessarily. At the same time the screenings can sometimes be missing some of the aggressive cancers because they’re detected too late to treat. What’s needed is for doctors to be able to find a way to determine which tumors will become fatal.

“Without the ability to distinguish cancers that pose minimal risk from those posing substantial risk and with highly sensitive screening tests, there is an increased risk that the population will be over-treated.” --Dr. Laura Esserman

This topic is of interest to me, particularly this month, because December is when I get to subject myself to various post-cancer screenings (CT scan, blood and urine tests) and an annual visit to my oncologist. Three years ago I had my first colonoscopy. I was 54 years old at the time, and 4 years beyond the recommended age for a first colonoscopy. Although no cancer or pre-cancerous polyps were found in the colon, during the procedure the gastroenterologist – who, lucky for me, was thorough enough to go beyond the end of the large colon - discovered a tumor at the very beginning of my small intestine. It turned out to be a rare cancer that can usually be cured with surgery if it’s not too advanced. In researching it, I read that it is usually a slow-growing cancer – you can have it for years without experiencing any symptoms - but the surgeon told me it could also be very aggressive. It just depends. Getting it removed was the most prudent thing to do (it’s amazing how quickly you want to rid it from your body when you learn you have cancer), so I had the surgery and fortunately the tumor was still contained and the cancer hadn’t spread elsewhere. No chemotherapy or radiation was necessary (my type of cancer doesn’t respond to it), and I’ll be considered cancer-free if I pass my annual screenings for four years. I just passed my third checkup on Wednesday.

But here’s my point: when I was first diagnosed, one of my friends chastised me for waiting so long to have my first colonoscopy. I admit I dragged my feet, despite my doctor’s recommendation. It’s my nature to avoid dealing with unpleasant things. But who knows? Had I not delayed having the procedure done, maybe the carcinoid tumor in my small intestine would have been too small to be detectable during a colonoscopy, and then much more advanced (or completely gone on its own) by the time I had my next screening. I have no way of knowing if that would be the case. But I’m not saying I’ll continue to buck my doctors’ recommendations for screenings (my oncologist set me up for another colonoscopy next month - so I got that going for me), but I can’t help but think – at least in my case – maybe some of it did come down to luck and timing.

MORE INFO
CNN story
Time magazine story
Huffington Post story
Cancer screening guidelines at About.com

Your Comments, Thoughts, Questions, Ideas

Liza's picture
Liza says:

Also, the new recommendations don't say that women under 40 shouldn't have mammograms. They say that women under 40 should talk to their doctors and get a sense of the risks and benefits of mammograms, and then GET THEM if they're indicated. As long as the guidelines aren't used to deny coverage for women whose doctors think they SHOULD have the exams, I think the guidelines are smart.

posted on Fri, 12/11/2009 - 1:00pm

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