BREAST CANCER OVERDIAGNOSIS BY COMMERCIALIZED SCREENING MAMMOGRAPHY: IS THE DOWNSIDE WORTH IT?

It is a no-brainer that mammography is invaluable diagnostically for

– a new breast lump, pain/discomfort  or bleeding.

– for followup of any pathology already present or likely eg the woman with obvious genetic risk of breast cancer;

– And for monitoring at baseline  and periodically on permanent appropriate physiological  HRT.

Rare women do present with distant spread of breast cancer before such cancer presents in the breast. But the hot chestnut* is:  how many well women  with clinically normal breasts at average risk of breast cancer  benefit or suffer by having screening – their apparently healthy ‘chestnuts’   squashed and irradiated regularly for decades looking for  preclinical cancer?

when the downsides also include time, pain, cost,  possible  increased risk from  cancer by both irradiation, pressure and needling, six unnecessary biopsies for each cancer found, and no clear evidence  that the resultant anxiety and  cancer therapy extends wellness and life?

A *chestnut includes an “old or stale joke (British)”, or ” music of sentimental value”!. The joke may indeed be on average-risk older women who are conned into having repeated- and risky-  screening mammography on their often most cherished ornaments.

The Breast Cancermongers – the screening mammography SMG  activists- now proclaim that 1 in 8 women ie 12.5%  will get breast cancer in her lifetime; but between 40 and 59yrs that number reduces to 1:15 ie about 7%. Without screening mammography of “normal” breasts, does breast cancer  actually present as a disease  in even   5% of sensible average-risk  women in the average at-risk middle decades?  and will prompt removal of such early  cancer before it presents itself to her/ the doctor with lump/pain/bleeding avoid  shortened lifespan  in any asymptomatic woman screened? Especially if appropriate balanced postmenopausal systemic human HRT is  continued lifelong to  reduce by 1/3 the  the far more common other major causes of  disease and deaths as well as deaths from breast cancer?

Note the disturbing figures  from Wiki:  “Of every U.S. woman screened, about 7% will be called back for a diagnostic session (although some studies estimate the number closer to 10%-15%). About 1% of those screened  will be referred for a biopsy; the remaining 6% are found to be of benign cause. Of the 1% referred for biopsy, about 0.35% will have a cancer and 0.65%will not. Of the  0.35% who do have cancer, about 0.2% have a low stage ie noninvasive cancer that will be essentially cured after treatment.” But who is to say that these 0.2% would ever have presented with cancer in their lifetime- ie are these the 2 out of 3 per 1000 overdiagnosed by SMG?

The incidence of BRCA in USA women in the 50-65yr agegroup is claimed to have risen  almost 50%  from 0.23 to 0.33% between 1975 and 2000, and has since fallen back about 25%. That almost 50% increase can only have been from the introduction of almost compulsory SMG. Despite advances in treatment, breast cancer mortality took almost 15years to start falling ie after plateau at about 0.07% for decades  till 1988, it has fallen steadily to 0.045% in 2006. A report in about 2002 says that ‘ Breast cancer incidence increased more or less steadily between 1940 and 1987 and has since stabilized at 0.1%.’

So we have a major credibility gap in reports from the USA: some authority says an overall incidence between 50 and 69yrs of 1%, another  say 0.25%.

More important, in 1999 Mettlin noted that “ some of the decline  in BRCA incidence and mortality is attributable to the lower mortality rates for women born between 1924 and 1938, who have reached the age where their breast cancer mortality experience most affects the overall rate; the  hypothesis being  that  increased fertility rates  following World War II reduced their risk of developing breast cancer and, therefore, of dying of breast cancer.”

The reality, not disease-mongering to promote SMG, was  simply put in 1995: “Between 1940 and 1982, breast cancer incidence rates in the United States increased by approximately 1% per year, largely in women over 40 years old. From 1982 through 1987, the rate of increase accelerated to around 4% per year and then leveled off – the rising rate  mainly attributable to early detection, due to the increase in breast cancer screening. The increase in breast cancer cases (with no change in incidence rates) among women 20 to 39 years old during 1970 to 1990 was due to a shift in the age distribution of the population. However, breast cancer mortality rates have remained fairly stable, with almost no change from 1950 to 1990 [42], increasing only about 0.2% per year [3]”

The issue remains a hot chestnut: like screening  colonic imaging and prostatic screening,  is this massive  universal individual screening of the apparent low-risk good, indifferent or bad for women, their men, families  and whoever has to pay the financial cost?

What the Wiki review does not say is that there are almost 20 000 articles already listed on Medline the past 50 years; and some 400 articles on screening mammography in asymptomatic women since 1966. Yet 60 year after mammography was invented,  the cost-benefit for women of the $billion SMG  industry is being increasingly questioned:

(paraphrased) Editorial “Overdiagnosis and mammography screening” 9 July 2009,    BMJ 2009;339:b1

The UK NHS recently scrapped its leaflet inviting well women to undergo mammography since it failed to mention the major harm of screening—overdiagnosis. The question is no longer whether, but how often, this occurs.

In a  new BMJ special on breast cancer,  Jorgensen  ea, Gotzche ea and Zahl ea,   again discuss evidence that screening has led to overdiagnosis of breast cancer not only in the UK, but also in Canada, Australia, Sweden, and Norway.

Overdiagnosis refers to detection of abnormalities that will never cause symptoms or death during a patient’s lifetime- when the cancer grows so slowly that the patient dies of other causes before it produces symptoms or when the cancer remains dormant (or shrinks).   

Because doctors don’t know which patients are overdiagnosed, we tend to treat them all.

Overdiagnosis therefore results in unnecessary treatment – perhaps in one in two (or even 2 in 3) women.

With   widespread efforts to diagnose cancer earlier, over-diagnosis has become an increasingly vexing problem.

H Gilbert Welch, professor of medicine, USA.