Examining the Dangers of Cancer Screening

Aug 1, 2009 by

Examining the Dangers of Cancer Screening

If mammograms worked as touted, death from breast cancer would be rare, since three-quarters of American women 40 and older get regular screenings (a total of 33.5 million per year). The modest decline in the death rate from the mid-1970s, when mammography was introduced, through the present can be attributed to factors other than screening, such as changes in treatment and the dramatic decrease in the use of Premarin and other cancer-promoting hormone replacement drugs. It doesn’t take a rocket scientist to figure out that mammograms do not substantially reduce risk of death from breast cancer.

2. The Most Deadly Cancers Are Missed
The flip side is that some people who are screened get cancer and die anyway. Test results aren’t always accurate. Sometimes cancer is there, but it’s missed (false negatives). In the case of mammograms, it could be a question of a poor-quality test or a radiologist who overlooked something. Even experienced radiologists don’t always interpret test results the same, and sometimes they just plain get it wrong.

The most likely reason that cancer is overlooked, however, is due to the nature of cancer itself. The deadliest cancers grow very rapidly. Screening can detect slow-growing cancers in their early stages, but you can see how aggressive cancers could be missed if you’re only looking for them once a year. Depending on the cancer’s growth cycle, it could crop up just months after screening and be far advanced by the time the next test rolls around.

3. The Pitfalls of False Positives
Far more common than false negatives are false positives-those cancer scares that occur when you’re told that your test is suspicious but, after further evaluation, turns out to be nothing. False positives lead to confirmatory testing such as ultrasound of the breast and prostate, CT scan of the lung, colonoscopy, and colposcopy of the cervix. These tests are at best inconvenient and at worst extremely unpleasant, as anyone who’s had a colonoscopy knows. They also often lead to biopsies, which are far more invasive and could possibly promote the spread of cancer.

Unfortunately, false positive rates are incredibly high. For mammography, it’s close to 10 percent. For every 100 women screened, 10 will require further workup. If you repeat this screening test every year for 10 years, your cumulative risk of having at least one false positive rises to 65 percent. This means that more than half of all women will get the terrifying news that their mammogram is abnormal-the first step on the slippery slope of intervention.

False positive rates are high for PSA as well, especially among older men. Some estimate that three-quarters of men who have a prostate biopsy based on an elevated PSA level do not have cancer. And lifetime false-positive risk for Pap smears is 75 percent.
Another consideration is the psychological trauma of cancer screening. Being told you might have cancer is a harrowing experience, and the lag time between retesting and getting a clean bill of health can be months.

4. Unnecessary Treatment
Even worse than the sound and fury created by false positives is unnecessary treatment. Yes, some lives are saved due to early detection and treatment. But not all cancers are the same. Some are deadly, treated or not; others are not fatal regardless of treatment. Dr. Welch calls the latter pseudodisease-small, slow-growing or nonprogressive cancers that you’d never know existed were it not for screening tests. Yet all too often, these innocuous tumors are attacked with a vengeance, often to the detriment of patients.

A prime example is prostate cancer. Since 1975, its incidence has more than doubled. But rather than having an epidemic of prostate cancer, what we have is an epidemic of detection. Although many more men are being diagnosed and treated, the death rate from prostate cancer has held steady at 3 percent.

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  1. Jo Firth

    Good story.
    Thankfully most of us do not get cancer, and the more we look, the more we are going to find.
    I target women under 50, and encourage them to take practical steps to immprove their health and hormonal balance, so they reduce their risk of possible diagnosis.
    Most women have breast “symptoms” of some kind – lumps, pain, tenderness, discharge, inversion, etc. Most will not be diagnosed. Knowledge is power, to reassure them they are OK, and to take steps to reduce their risk, by improving their condition and getting on and enjoying life.
    There are options out there for women of all ages, now, to monitor their breast health and look for the early clues that may cause a problem in the future. Easier to aim to nip it in the bud early.

  2. Eliz52 (Aust)

    Totally agree with you, but try being a woman and refusing a pap test. Cervical screening has always been considered mandatory unlike prostate screening. I believe it’s because the hugely expensive program (full of vested interests) rests on a knife edge and was never suitable for mass screening – a rare cancer and an unreliable test means forcing most women into testing and harming most of them to some degree.
    I was onto them from the start, but it’s been awful to see the control, disrespect, arrogance, rudeness, coercive measures, pain, indignity, humiliation and damage this testing causes to help a very small number of women and all with no informed consent. Very few women give informed consent for the test and most don’t even consent – they’re forced to have the test if they want birth control pills or HRT and the test is often required if you want to join a volunteer program or the military. Those measures are employed in the States, here doctors use the consult situation to ambush women, achieve targets and collect payments from the Govt and we’re subjected to dishonest scare campaigns by Papscreen.

    Less than 1% of women benefit from smears (around 0.65% is the lifetime risk of cervical cancer in Australia, it’s also less than 1% in the States) but 95% of American women and 77% of Aussie women will be referred after an “abnormal” pap test – almost all are false positives. Many women think these false positives were about cancer and go on to consider themselves cancer survivors. Of course, some treatment leaves no pathology so women assume they had cancer or pre-cancer that would have progressed to cancer.
    This means most women believe this cancer to be rampant – the level of fear about this cancer is out of all proportion to the actual risk of this rare cancer.
    In Angela Raffle’s book, “Screening” she mentions mouth cancer occurs as frequently as cervical cancer – few women worry about mouth cancer and we don’t have every tiny odd-looking cell blasted off or cut out, do we? Screening has created the fear, not the cancer.
    Some women who have unnecessary biopsies and treatments are left with psych issues and/or cervical damage – cervical stenosis (that can mean endometriosis, infections, surgery, infertility) or cervical incompetence (miscarriages, high risk pregnancy requiring cervical cerclage, premature babies and c-sections)…
    My younger sister had a false positive and ended up having a cone biopsy – a devastating experience, yet this procedure is often dismissed as “minor” by doctors and Papscreen.
    This testing and treatment involves a very private part of our body – yet there is zero respect for a woman’s right to REAL information and a say in whether she tests or not – it’s like running ewes through sheep dip. Women who choose not to screen are called uneducated, reckless, silly, crazy, lower-class…etc
    We get half-truths, manipulations of the truth, lies, fiddled-with statistics, scare campaigns and our doctors receive UNDISCLOSED financial incentives when they reach targets for pap tests (in the UK, NZ and Australia) – so our doctors have a potential conflict of interest. Papscreen often refer to third world rates of cervical cancer to scare and mislead women, they don’t mention false positives even though 77% of women who screen will have one and they exaggerate the risk of the cancer and the benefit of the test and they get away with it decade after decade ….I’ve never heard a Dr challenge the “information” that is provided to women.

    I don’t have pap tests, as an informed woman, doctors back off very quickly. I also declined mammograms due to concerns about false positives and over-diagnosis.

    There is no informed consent in women’s cancer screening.
    Hopefully, more articles like this will provide women with the information they need and the confidence to defend themselves in consult situations and make the right decision for their body, their level of risk. Cancer screening is an option, not a law, for men AND for women.

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