DATED; 13TH NOVEMBER 2003
The New Zealand Press Association:
is to express my support for including women from age 40 into regular, high
quality, organized screening for breast cancer. Those who would dogmatically
exclude women from the benefit of this proven life-saving method, do not fully
understand the biology of this disease, and cite randomized trials that have
been initiated before sufficient knowledge has accumulated about the natural
history of this disease and therefore have been carried out with interscreening
intervals which are too long.
basic issue is that the growth rate of the different breast cancer subtypes have
equally short preclinical detectable phase (so-called sojourn time, i.e. the
time-difference between mammographic detectibility and clinical detectibility)
in premenopausal women, while there is a considerable spread in the length of
this preclinical detectable phase according to tumor type among postmenopausal
women. Also, it is fundamental to take the propensity of worsening of the
histologic grade into account (the so-called phenotypic drift, i.e. the
propensity for a less aggressive tumor to become more aggressive during tumor
to our research 8 breast cancers out of 10 (81%) have the potential for
dedifferentiation (worsening of malignancy grade during tumor growth) in age
group 40-54, while this figure is one out of two (about 50%) in women aged 55
and older. This clearly tells us that more breast cancers benefit from early
detection in "younger women"...leading to the conclusion that "If
anybody is to be screened, it should be the younger women"!
recommendation of the Swedish government is that screening should begin from age
40 and above.
have been screening age group 40-49 for 26 yrs now - and will continue to do so.
American Cancer Society clearly recommends screening for women aged 40 and
above. Their new guidelines are available at: http://caonline.amcancersoc.org/cgi/content/full/53/3/141
randomized controlled trials clearly underestimate the benefit of screening, and
it is very difficult for the individual woman to "translate" the
"general to the specific". To answer the question: “What will be my
personal benefit if I attend regular screening?” In order to answer this
question more clearly, we have published new data in The Lancet. The Abstract of
our publication is included below.
of Uppsala, Uppsala, Sweden
Department of Mammography
Central Hospital, Falun, Sweden
2003 Apr 26;361(9367):1405-10.
service screening and mortality in breast cancer patients: 20-year follow-up
before and after introduction of screening.
L, Yen MF, Vitak B, Chen HH, Smith RA, Duffy SW.
of Mammography, Central Hospital, Falun, Sweden.
The long term effect of mammographic service screening is not well established.
We aimed to assess the long-term effect of mammographic screening on death from
breast cancer, taking into account potential biases from self-selection, changes
in breast cancer incidence, and classification of cause of death. METHODS: We
compared deaths from breast cancer diagnosed in the 20 years before screening
was introduced (1958-77) with those from breast cancer diagnosed in the 20 years
after the introduction of screening (1978-97) in two Swedish counties, in 210000
women aged 20-69 years. We also compared deaths from all cancers and from all
causes in patients diagnosed with breast cancer in the 20 years before and after
screening was introduced. In the analysis, data were stratified into age-groups
invited for screening (40-69 years) and not invited (20-39 years), and by
whether or not the women had actually received screening. We also analysed
mortality for the 40-49-year age-group separately. FINDINGS: The unadjusted risk
of death from breast cancer dropped significantly in the second screening period
compared with the first in women aged 40-69 years (relative risk [RR] 0.77 [95%
CI 0.7-0.85]; p<0.0001). No such decline was seen in 20-39 year olds. After
adjustment for age, self-selection bias, and changes in breast-cancer incidence
in the 40-69 years age-group, breast-cancer mortality was reduced in women who
were screened (0.56; 0.49-0.64 p<0.0001), in those who were not screened
(0.84 [0.71-0.99]; p=0.03), and in screened and unscreened women combined (0.59
[0.53-0.66]; p<0.0001). After adjustment for age, self-selection bias, and
changes in incidence in the 40-49-year age-group, deaths from breast cancer fell
significantly in those who were screened (0.52 [0.4-0.67]; p<0.0001); and in
all women, screened and unscreened combined (0.55 [0.44-0.7] p<0.0001) but
not in unscreened women (p=0.2). In both 40-69-year and 40-49-year age-groups,
reductions in deaths from all cancers and from all-causes in women with breast
cancer were consistent with these results. INTERPRETATION: Taking account of
potential biases, changes in clinical practice and changes in the incidence of
breast cancer, mammography screening is contributing to substantial reductions
in breast cancer mortality in these two Swedish counties.
BACK TO: BREAST CANCER INFO AND PETITION