A year since our last review– which summarized studies till then- has anything changed?
Medically, “screening” is the search for a hidden disease in someone who has no known risk factors for or symptoms of disease. Apart from the far higher risk of all cancers in smokers, in non-smokers the commonest cancer is prostate cancer PRCA – cancer causes perhaps 24% of male deaths of which 1/10th are from PRCA; whereas breast cancer BRCA is the commonest in women, but all cancers kill only 3% of women – 1/7 from BRCA; followed by colon cancer..
And of course screening is justified only if detection of an unexpected problem is going to make a significant difference. Certainly all the evidence is that detecting a silent PRCA in an otherwise well man makes no difference to his chances of dying from such cancer. It is also unclear whether the cost, radiation risk, bother of mammography, and about 5 unnecessary breast biopsies for each small cancer found, actually extend the woman’s lifespan, as opposed to waiting till the cancer is detected as a lump. Earlier detection may simply lengthen the lifespan spent living with known cancer.
Many men and women have a previously undetected incidental cancer at autopsy. And there is no point in screening if they will in any event not accept treatment for cancer- some women (whether from faith, fear or ignorance) choose to ignore the growing lump, accept natural disease progression, even though simple excision of a small breast lump can reduce the deathrate from clinical BRCA to below 5%, thus extend life by decades.
This contrasts with compulsory regular screening of the seemingly well for eg overweight, glaucoma, hypertension (or cervix cancer in sex workers), where early detection and treatment of silent disease can respectively add years to health.
But risks of cancer are fairly commonly found in the history and lifestyle: obesity and diabetes; occupation; lifetime number of menstrual cycles, total intake of oral sex hormones, tobacco, alcohol etc; and especially family history of deaths under perhaps age 70years from one of the sexhormone related cancers (breast, prostate, endmetrium, ovary, colon).
Excluding women with such risk factors –who should be screened with far more conviction- this week a radiologist soberly publishes What is the point: will screening mammography SMG save my life? by calculating the life-saving absolute benefit of SMG in reducing breast cancer mortality in women ages 40 to 65. By adjusting the SEER Program 15-year cumulative breast cancer mortality to account for the separate effects of SMG and improved therapy, they calculated the reduction in absolute death risk, and the survival percentages without and with screening.
RESULTS: The number needed to screen repeatedly is 1000/1.8, or 570. The survival percentage is 99.12% without and 99.29% with screening. The average benefit of a single SMG is 0.034%, or 2970 women must be screened once to save one life. Less than 5% of women with screen-detectable cancers have their lives saved.
It is questionable (except for profit of the disease industry ie the economy) whether women should be frightened into having regular costly SMG by being told that “1 in 8 will get breast cancer”, or more truthfully that – unless they have high risk factors- SMG will reduce their risk of dying from BRCA by 0.17% from 0.88% to 0.71%?
As regards the putative benefit of screening: it is the ABSOLUTE risk reduction number that matter to patients- not the relative 19% decrease in risk, since 19% of say 50% is an absolute significant fall of perhaps 10%, whereas 19% of 0.88% is only 0.17% risk reduction over decades- hardly worth the cost and bother.
When attention should rather be focused on improving lifestyle and diet, and multisystem-protecting supplements: vitamins, minerals and biologicals- eg fish oil, coQ10, arginine, carnitine, chondroglucosamine, appropriate hormones and herbs- which are known to reduce the major degenerative diseases (cancer; depression, vascular; lung; kidney; digestive; diabetes; arthritic; fracturing; and dementing), and common infections, and all-cause premature mortality, by half.
All-cancer mortality in men was 0.23%pa of which 11% were from PRCA;
all-cancer mortality in women was 0.16%pa of which 12.5% were from BRCA.
Thus while men get more PRCA, their absolute mortality is the same as from BRCA in women; the respective deathrate relative to incidence from PRCA in men is 6.6% lower than from BRCA in women- BUT the mean age in women at 61yrs is 7years younger than PRCA in men, respective peak age at 60yrs 10 yrs younger than in men, with occurrence in women from age 20yrs compared to from 35yrs in men.
Hence women suffer BRCA – and body image disfigurement – much younger than do men PRCA. But women with BRCA do not have the physical urinary and erectile problems that PRCA and it’s surgery cause in men.
Looking at the bigger picture of the CDC deathrates for 2005,
in men PRCA caused 0.02%pa out of total cancer deathrate of 0.2%pa ie 10% of all cancer deaths and 2.3% of all deaths (0.827%pa), compared to heart and all vascular disease causing 35% of all deaths;
in women BRCA 0.027%pa (same as diabetes rate) out of total cancer deathrate of 0.18%pa ie 15% of all cancer deaths and 3.1% of all deaths (0.825%pa); compared to heart and all vascullar diseases causing 36% of all deaths.
Colorectal cancer caused similar deathrate – 0.018%pa – in men and women.
Thus breast and prostate cancers in USA cause only about 1/12 to 1/15th of the deaths from the overwhelming cause of aging mortality- heart and vascular disease!
The reality is that – even if there is no family history of fatal breast cancer- it is awareness, regular breast selfexamination that matters, and if a new pain or lump or tenderness or bleeding is found, prompt medical consultation that can nip a small cancer in the bud before it can spread.
Thus, rather than having men and women at average risk obsess about costly but low-yield (breast, prostate and colon) cancer screening, both adults and their healthcare providers should focus 10 times harder on dealing with the main underlying cause of premature cardio/vascular (and cancer and arthritic and immune) disease- increasing overweight leading to diabetes, obesity and the common degenerative problems. This is especially germane when better attention to diet, lifestyle and appropriate early prescription of preventative metformin and the scores of other supplements can halve the rates of diabetes, obesity and thus all the major common ageing diseases- including sudden death.