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Ken Lee’s result that high med spending states tend to have more cancer deaths inspired me to look up the med lit on cancer screening. I turned to Cochrane Reviews, high quality med lit reviews. Here are the reviews I found on cancer screening:
Eight eligible trials were identified. We excluded a biased trial and included 600,000 women in the analyses. Three trials with adequate randomisation [with 260,000 women] did not show a significant reduction in breast cancer mortality at 13 years; four trials with suboptimal randomisation showed a significant reduction in breast cancer mortality with an RR [risk ratio] of 0.75 (95% CI 0.67 to 0.83). … Significantly more breast operations (mastectomies plus lumpectomies) were performed in the study groups than in the control groups: RR 1.31 (95% CI 1.22 to 1.42) for the two adequately randomised trials. … Breast cancer mortality was an unreliable outcome that was biased in favour of screening, mainly because of differential misclassification of cause of death. The trials with adequate randomisation did not find an effect of screening on cancer mortality, including breast cancer, after 10 years (RR 1.02, 95% CI 0.95 to 1.10) or on all-cause mortality after 13 years.
Four RCTs [randomized controlled trials] … involved 327,043 participants in Denmark, Sweden, the United States, and the United Kingdom. … Combining the four RCTs show that screening results in a statistically significant relative reduction in CRC mortality of 16% (fixed and random effects models: RR 0.84, 95% confidence interval [CI] 0.78–0.90) … Combining the four RCTs did not show any significant difference in all-cause mortality between the screening and control groups.
Five RCTs with a total of 341,351 participants were included in this review. … The methodological quality of three of the studies was assessed as posing a high risk of bias. Our analysis of the five studies showed no statistically significant reduction in prostate cancer-specific or all-cause mortality among the whole population of men randomised to screening versus controls.
We included seven trials (six randomised controlled studies and one non-randomised controlled trial) with a total of 245,610 subjects. There were no studies with an unscreened control group. Frequent screening with chest x-rays was associated with an 11% relative increase in mortality from lung cancer compared with less frequent screening (RR 1.11, 95% CI 1.00 to 1.23).
Wow. While cancer screening does consistently lead to more cancer detection and more cancer treatment, it consistently doesn’t lead to lower mortality.
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I know many believe the pap test is the most effective screening test in history. I can't agree...There are no RCT's for pap testing and also, this was always a rare cancer, in decline before screening started and those factors are still having an effect on the incidence and death rate. Dr Gilbert Welch points out things like better hygiene and less sexually transmitted disease in his book, "Over-diagnosed". I'd add more hysterectomies (1 in 3 US women will have one by age 60!), fewer women smoking, better condoms etc...It's true that stomach cancer has also fallen by a similar or greater margin with no screening at all, yet you can bet if there was a screening test, they'd be grabbing the credit.
The thing that writes off cervical screening for me: vast over-detection and potentially harmful over-treatment. I also hate the way cancer screening is regarded as compulsory for women, elective for men. Women don't get balanced and complete information and our legal right to give informed consent for cancer screening is dismissed...in the States and Canada women are routinely coerced into cancer screening and often, over-screening and reckless screening. (screening women not yet sexually active from age 21) I know American doctors refuse women birth control pills, HRT, migraine meds and even all medical care until they agree, to not only cancer screening, but completely unnecessary and potentially harmful breast and gyn exams. (these exams are not recommended in asymptomatic women here and in many other countries)There is a double standard in cancer screening.
In Australia we also over-screen (not as badly as the States) and there is zero respect for informed consent (for women) - our GP's even receive an UNDISCLOSED target payment for pap testing (about to be raised to 65% of eligible patients)...this is unethical as it creates a potential conflict of interest. These payments were recently changed in the UK, thanks to the work of some amazing advocates for informed consent for women.
Here we screen women from 18 (sometimes earlier) knowing this is of no benefit, but exposes these women to harm and great worry.
"No country in the world has shown a reduction in the incidence of or the mortality from cervical cancer in women under 30, irrespective of cervical screening. Many countries do not perform cervical screening on women under 30"..."Cervical cancer screening" a handout for doctors (not women!) in "Australian Doctor" 2006 by Assoc Prof Margaret Davy and Dr Shorne.Still we continue to test young women....
Finland has the lowest rates of cc in the world and sends the fewest women for colposcopy/biopsies (fewer false positives) - they offer 5 to 7 tests, 5 yearly from age 30. (even this schedule sends 35%-55% at some stage for follow-up)Australia often boasts about having the lowest mortality rate in the world, but we keep our shameful over-detection and over-treatment rates under wraps. This low rate is achieved at a terrible cost paid by the healthy population of women - the more than 99% who'd never have an issue with this cancer and all with no informed consent.
Dr Angela Raffle, UK screening expert showed that 1 in 3 pap tests will be "abnormal" in women under 25 - false positives caused by normal changes in the maturing cervix and from harmless and transient infections. Cervical cancer is rare, very rare before 30 and screening doesn't change the incidence or death rate in young women anyway.It is unethical to test women under 30 and definitely before 25 and to test any woman without informed consent.
We also test 2 yearly and this means lots of false positives for no additional benefit - it's over-screening.77% is the lifetime risk of referral for colposcopy and usually some sort of biopsy to cover a 0.65% lifetime risk of cervical cancer. Take out false negative cases and considering other factors are affecting the incidence and death rate - fewer than 0.45% of women are helped (assuming any woman is helped) The States it's even higher - lifetime risk of referral - 95%...(DeMay article at Dr Sherman's site)This amount of over-detection and over-treatment IMO, makes this testing unsuitable for population screening. I don't believe it would be approved today.Now we have a program that is highly lucrative, very political and highly emotive....it helps few and harms (to some degree) many....Some women end up worse off after unnecessary biopsies and procedures like LEEP - cervical stenosis, (infertility, infections, endometriosis and may need surgery if the cervix is scarred shut) cervical incompetence - miscarriages, high risk pregnancy that may require cervical cerclage, more c-sections, premature babies and psych/psychosexual issues.No one seems to care about these women and there are lots of them - the entire focus is on screening and the incidence and death rates for this rare cancer.My own younger sister had a cone biopsy after a false positive pap test - a devastating experience.
It's the same with mammograms - we don't get honest and complete information and there is no respect for informed consent.Thankfully, the UK has some great people prepared to speak up and warn women of the risks. Professor Michael Baum, UK breast cancer surgeon gave another informative lecture at UCL recently, "Breast cancer screening: the inconvenient truths" - at the Medphyzz site.It's also possible to get to the facts behind cervical screening - Dr Joel Sherman's patient privacy site under women's privacy issues has lots of great references, including research by Angela Raffle. "1000 women need regular smears for 35 years to save one woman from cc" (BMJ:2003/4) plus over-detection and over-treatment rates.
It's hard to understand why we spend a small fortune "fighting" this rare cancer when there are FAR greater threats to our lives out there...it says to me that these programs have little to do with our health. The priorities are skewed by pressure/lobby groups, political and vested interests. ($$$)I think cancer screening is a great threat to our health, rights and lives.I made an informed decision, as a low risk woman, not to have pap testing more than 25 years ago and more recently, rejected mammograms. I didn't get the information I needed from my doctor.More than ever before we need to do our own reading, spread the word and make informed decisions about our health care. I don't give a damn about screening targets or my GP's incentive payment...Is this really in MY best interests?
Can it also be assumed that a certain percentage of people who seek screenings (perhaps a large percentage) are taking action and getting screened specifically because they know that cancer runs in their family. And those who don't get screened probably aren't worried because it does not run in their families.
So, screened people who ended up with cancer mortality versus non-screened people who ended up with cancer mortality seems misleading to me.
Maybe there should be a study on the effectiveness of screenings, specifically for people who have cancers that run in their family and a separate study for the same thing specific to people who don't have cancers that run in their families.
My guess is that if you looked at the data that way, both data sets would show that screenings helped.