-  submission to the Select Health Committee, 25th February 2004

Dr Jackie Blue, Breast Physician, St Marks Woman's Health, Auckland

Dr Benji Benjamin					Dr Barbara Hochstein
Clinical Director					Breast Radiologist
Radiation Oncology					Lakes Radiology and Lakeland Health	
Auckland Hospital					Rotorua
Dr David Benson-Cooper				Mr Wayne Jones
Breast Radiologist					Clinical Director - General Surgery Auckland Hospital
Mercy Radiology						Head of the Auckland Breast Surgery Unit
Auckland						General Breast and Endocrine Surgeon
Dr Sonja Freese							
Breast Physician					Dr Margie Weston
Breast Associates					Breast Radiologist
Auckland						Auckland
Dr Sue McKeage
Breast Surgeon
Mr Stan Govender
Breast Surgeon
Dr Marli Gregory
Breast Physician
Mr John Harman
Breast Surgeon
Dr Heather McIntyre
Breast Physician
Dr Karen Parker
Breast Physician
Dr Ken Judd
Breast Radiologist
Breast cancer in New Zealand
Breast cancer has been steadily increasing in New Zealand over the last 30 years and as a 
comparison presents a far greater health issue than cervical cancer. The breast cancer death 
rate has reduced 19% over the last decade. This reduction has been mirrored internationally 
and is believed to be due to the use of adjuvant treatment. BreastScreen Aotearoa (BSA) began 
in late 1998 and as a result of increased early detection, the 1999 registration rate 
increased sharply (Fig 1). There was an 8% increase in the registrations from 1998 to 1999, 
which is directly attributable to increased diagnosis in the BSA target age group 50-64 group (Fig 4). 
Cervical cancer does not have the same impact as breast cancer; almost 10 times more women die 
of breast cancer each year than cervical cancer.  Breast cancer becomes more common as women age 
and as NZ has an ageing 'baby boomer" population, in the next decade we will see large numbers 
of women diagnosed with breast cancer.
New Zealand's breast cancer incidence is similar to Australia. However, Prof David Skegg when 
he compared the 2 countries concluded that NZ women have a 28% greater chance of dying of 
breast cancer compared with Australian women (1). BreastScreen Australia began in 1991. 
Screening mammography has been offered to Australian women in the 40-49 yr age group since the 
outset and although this group is not actively recruited, 20% of the eligible group has mammography 
through the Australian programme. It is impossible to tease out as to why women with breast cancer 
in New Zealand have a greater chance of dying of their disease compared with their Australian counterpart. 
Improved survival for those women who have screening mammography in the 40s is just as valid a reason as 
is more effective and timely treatment services.
Breast cancer - actual numbers per decade
Of the over 2000 women diagnosed with breast cancer annually in New Zealand, 20% are in the 40s.
In comparison, women in the 50s accounts for 25%, women in the 60s - 21%, women in the 
70s -16% and women 80 and over accounts for 13%. The proportion of women who are diagnosed 
in the 40s is not an insignificant number (Fig 2).
Breast cancer - registration rates over the last 5 years
Breast cancer is more common as women age and this is reflected in breast cancer registration 
rates over the last 5 years of available data (1997,1998,1999,2000,2002). However, it is 
important to note that this data is inevitably skewed; the introduction of BreastScreen 
Aotearoa for women 50-64 years in late 1998 resulted in a marked increase in the registration 
rate, which is directly attributable to increased diagnosis in the 50-64 group. (Fig1,3,4). 
The skewing of the data for women 50-64 year with the introduction of BSA serves to understate 
registrations in 40-49 age group. 
Breast cancer death- actual number and rates
The actual numbers and death rate from female breast cancer reflects the increasing 
registration rate; it is an established fact that breast cancer is more common as women age. 
In 1999 for women in the 40s and 50s, breast cancer by far is the commonest cause of 
death in these respective age groups (NZHIS). For the 30% of women who die from this 
disease, death from breast cancer may be some years after diagnosis and therefore death 
rates of women in 40-49 age group more accurately reflects those women diagnosed in the 
30s. Similarly the death rate for women in the 50s may more accurately reflect those 
women who were diagnosed in the 40s. The sharp increased breast cancer death rate in 
women 85 years and over may reflect the difficulty in establishing an accurate cause of 
death in this age group (Fig 5,6). 
Auckland Breast Cancer Study Group (data reproduced with permission from the ABCSG)
Since June 2000 the Auckland Breast Cancer Study Group (ABCSG) have reviewed data from all 
breast cancer cases occurring in the Auckland region, Currently 1800 consented patients are 
recorded on ABC register. The ABCSG data confirm that women in the 40-49 yr age group have 
a 10% higher rate of the most aggressive tumours (Grade 3), than women over 50 years. This 
data is consistent evidence that cancers in premenopausal women are faster growing and more 
aggressive than in post-menopausal women. It is for this reason that women 40-49 require 
annual mammography compared with 2-yearly mammography for women over 50 years. Over 
75% of women in the 40-49 years age group presented with a palpable lump, compared to 
43% of women eligible for screening. This data also demonstrates that clinically detected or 
palpable cancers have a higher rate of lymph node involvement, which is 6% higher in the 40-
49 age group compared to clinically detected tumours in women eligible for screening. Lymph 
node involvement is a negative prognostic indicator.

Flawed arguments levelled against screening mammography in the 40s
The standard arguments that have continued to be used against screening women in the 
40s are flawed and no longer can be justified.
1. Women in the 40s have dense mammograms. Therefore cancers will be missed and there 
will be more false positives.
There is no magical change in mammographic denseness at age 50 years. Over 
time, breast tissue gradually becomes more fat replaced. At age 30 years approx 
90% of women have mammographically dense tissue and this changes by 1-2% per year 
such that at age 65-70 years, 60% of women will have fat replaced breast tissue. 
As such, there is no significant difference with regards to mammographic denseness 
when women 40-49 and 50-59 are compared. Breast cancer is more common as women age 
and when this is taken into consideration, recent Australian data from 
BreastScreen Victoria confirms that cancer detection rates are comparative and 
recall rates from screening mammography are similar. The recall rate for first time 
attenders is within the recognised international and BSA target for both groups 
(2, Fig 9,10). The recall rates for subsequent attenders for both women in the 40s 
and 50-69 yrs is slightly outside the international and BSA target. It is a credit to 
BSA that lead providers consistently meet stringent BSA targets for women 50-64 yrs 
and because of the quality of providers in NZ would be able to meet targets for women 
40-49 yrs. Of note, Victoria (Australia) has a similar population to NZ.
2. Mammograms in the 40s will make women anxious - refer to submission Danute
   Ziginskas, Clinical Psychologist.
3. The risks and harms of mammography in the 40s outweighs any benefit. 
   Other risks of screening mammography include cancers that are detected but whose 
   outlook is unaltered by an earlier diagnosis and over-treatment of abnormalities such as 
   ductal carcinoma in situ (DCIS). There is no simple way to compare the risks versus the 
   benefits; they will be perceived differently by different women.
4. The benefit of screening appears delayed in younger women. The delayed benefit is 
   because a woman has turned 50 and screening should therefore start at 50 years.
   It is not clear why the benefit is delayed in younger women or indeed what the 
   significance of this is. Possible factors that influenced the apparent delayed in benefit 
   of screening are that younger women having faster growing cancers. Importantly all the 
   controlled trials had variable screening intervals (12-33 months) and we now know that 
   women in the 40s need annual mammography. Experts believe that if the correct annual 
   screening interval had been applied to this age group, the time it would take to see the 
   benefit of screening would be similar to the 50 and over age group (4-5 years after screening 
   begins)(3). Importantly the window of opportunity to prevent death from breast cancer may 
   occur early in its growth even though it may not be fatal for many years.
5. The screening trials conducted in the latter half of last century do not show a
   benefit in screening women in the 40s
   Over the past thirty years there have been eight controlled trials looking at 
   whether regular screening mammography reduces the number of women dying from 
   breast cancer. The eight controlled trials varied in recruitment of participants, 
   age groups screened, the time between mammograms or screening interval, mammography 
   protocols, control groups, and size. Only one trial specifically looked at the 
   40-49 year age group (Canadian CNBSS-1). The Canadian trial is now considered by 
   experts to be flawed due to selection bias of the screened group. Over time there 
   has been intense review and re-analysis looking at different combinations of the 
   controlled trials. In 2002, the United States Preventative Services Task Force 
   (USPSTF) analysed all the trial data to date and when the Canadian trial was excluded, 
   determined that there was a 20% reduction in breast cancer death in women who have 
   screening mammograms in the 40s (4). This is worst-case scenario. Tabar has emphasized 
   that the meta-analyses of women in the 40s underestimates the benefit of screening (5).
   In contrast there are individual trials such as the Gothenberg trial, which showed 
   a 42% reduction in breast cancer mortality for women 40-49yrs (4).
   However, it is believed that if a theoretical annual screening interval to the 
   40-49 yr group, the reduction in breast cancer death is thought to be at least 
   as good as and may even be better than the over 50 year result of 30% reduction 
   in breast cancer death. For instance, the Gothenberg trial (6), which screened women 
   40-49 yrs every 18 months, showed a 42% reduction in breast cancer death. Not all 
   women invited for a screen had a mammogram but these women are included in the 
   calculations. It has been theoretically calculated that if 100% of women had a 
   mammogram the reduction in breast cancer deaths would be 55% and if the women had 
   an annual mammogram the reduction in mortality would be as high as 73%.
Other considerations for screening women in the 40s
An analogy to breast cancer development in women in the 40s is like a snowball rolling 
down a mountain. Just as a snowball gets bigger and gains speed, breast cancers in the 
40s get more aggressive and bigger (potential for dedifferentiation or worsening of 
malignancy grade during tumour growth). Tabar estimates that 8 breast cancers out of 10 
(81%) have the potential of dedifferentiation in the 40-54 age group, while this figure 
is one out of two (50%) in women aged 55 and older (5).  
Importantly when a young woman in her 40s is saved from dying from breast cancer there 
is more life-years saved compared to an older woman. In New Zealand since 1992, the 
numbers of live births for women aged between 35-45 years has doubled from 10% of the 
total live births to almost 20% (7). The social fallout to the family is huge when a 
young woman dies. 
The actual benefit from breast cancer screening is primarily important to the individual 
woman who is interested in reducing her risk of dying from breast cancer. Women in the 
40s must have the absolute right to make an informed decision and be offered choice. 
Countries such as Australia who are currently offering half pie screening in the 40s 
but not actively recruiting this age group need to get off the fence. New Zealand has 
an opportunity to be a leader and not a follower in women's health.
(1)	Skegg et al, NZ Med J 2002; 115:205-8
(2)	A decade of achievement BreastScreen Victoria 1992-2002 and BreastScreen Victoria 2001, Annual Statistical Report
(3)	Kopans, Breast Imaging 2nd Edition, Lippincott Williams and Wilkins
(4)	Humphrey et al Summary of the Evidence - Breast Cancer Screening http://www.ahrq.gov/clinic
(5)	Tabar statement to the NZPA 2002
(6)	Bjurstam et al, Journal of the National Cancer Institute. (22): 53-5, 1997.
(7)	Statistics New Zealand, www.stats.govt.nz