Position Statement
Yearly breast screening mammograms for women
40-49 years of age
April 2008
Position
The New Zealand Breast Cancer Foundation recommends
yearly breast screening mammograms for women 40-49
years of age.
Breast Screening Mammogram
A breast screening mammogram checks women for early,
unsuspected breast cancer; women who have no signs or
symptoms of breast cancer – ‘well’ women.
Benefit
Benefit of a breast screening mammogram:
- Best method to detect an early, unsuspected breast
cancer
- Early detection and diagnosis of a breast cancer
increases the likelihood of successful treatment and
survival
Justification
Reasons for the Foundation’s position statement:
- The time during which a breast cancer is potentially
detectable by breast screening mammography is shorter
in women aged 40 to 49 years compared to women in
their 50s, 60s and 70s(ref. note 1)
- Breast cancer in women in their 40s can be:
- More aggressive (grows more rapidly) as opposed
to women who have gone through the menopause (ref. notes 2,3)
- More difficult to detect on mammogram x-ray
images due to the increased density of their breasts.
In NZ, up to 25% of breast cancers are not detected
in women in their 40s, compared with 10% not
detected in their 50s (ref. note 4). Therefore, there is a need
for detection and diagnosis at the earliest possible
stage.
- Between 40-49 years of age, the evidence for regular
breast screening mammography is perhaps less
compelling than for women in their 50s, 60s and 70s.
Nevertheless, there is a powerful and consistent trend,
based on well conducted clinical trials of annual breast
screening mammography which shows a reduction in
the death rate between 15-17% in the 40-49 age group (ref. note 5).
- In 2004, close to 20% of all diagnoses of female breast
cancers in NZ were between 40-49 years of age (ref. note 6).
| Age in years (females) |
| 40-44 |
45-49 |
40-49 |
| 188 (7.96%) |
277 (11.73%) |
465 (19.69%) |
Australian breast cancer statistical data for women aged
40-49 years is similar to New Zealand’s data (ref. note 7).
Benefit versus Risk
It is the Foundation’s view, after careful consideration
of the literature, the benefit of breast screening
mammography in this younger age group outweighs any
potential risk.
Potential risk of breast screening mammography may
include:
- A false positive
A false positive is when a screening mammogram
suggests there is a breast cancer when, in fact, there
is no breast cancer (ref. note 8). A false positive means a woman
will be recalled for further investigations ranging from
repeat mammography and/or ultrasound, biopsies, etc.
These investigations and the resultant fear and anxiety
would not have occurred in the absence of screening.
- A false negative
A false negative is when a screening mammogram
misses a breast cancer even though a breast cancer is
present (ref. note 8). False negatives occur partly because most
young women (under 50 years of age) have denser
breasts, and dense breast tissue makes it more difficult
to read mammogram images by a radiologist, i.e. spot
problems (ref. note 9).
Screened women need to be aware that mammography
has limitations. In women under 50 years of age,
screening mammograms detect about 75% of
unsuspected cancers, and in women 50 years of age
onwards, about 85-90% of unsuspected cancers are
detected4. Therefore, women under 50 years of age
have approximately a 25% chance of having a breast
cancer missed with routine screening mammography.
These statistics highlight the need for all women,
particularly those under 50 years of age, to report any
breast changes to their family doctor without delay,
even if a recent screening mammogram was normal.
Breast changes that require attention are:
- A new lump or thickening
- A change in breast shape or size
- Puckering, dimpling, or a change in colour of the skin
- Any change in a nipple such as a discharge or a nipple that
starts to turn inwards
- A radiation induced breast cancer
The benefit of breast screening mammography (early detection
of breast cancer) outweighs the risk from radiation exposure in
women of this age (ref. note 10).
Family Doctor
It is important for women to gain an understanding of breast
screening mammography. The Foundation recommends women
40-49 years of age discuss with their family doctor the following:
- Benefit and risk of having a breast screening mammogram
- Their personal risk of developing breast cancer
Personal risk factors to consider are:
- Age
- Family history of breast or ovarian cancer
- Previous breast biopsies
- Long term hormone replacement therapy
- Obesity
- Alcohol
Personal risk will determine the appropriate age that breast
screening mammograms should commence.
BreastScreen Aotearoa (BSA)
The New Zealand (NZ) Government’s breast screening
programme – Breastscreen Aotearoa – checks women with no
breast cancer symptoms for unsuspected breast cancers between
45 and 69 years of age with a free screening mammogram every
second year. The programme’s aim is to reduce the number of
New Zealand women who die from breast cancer (ref. note 4).
For women 40-49 years of age, yearly screening mammograms
would not all be free, as BreastScreen Aotearoa covers women
from 45-69 for a free screening mammogram every second year.
Therefore, women from 40-44 years of age would need to pay
for each of their yearly screening mammograms (5 screening
mammograms), as well as, the alternate years between 45-49
years of age (2 screening mammograms). The cost of a screening
mammogram at a private NZ breast clinic/radiology group
service varies from approximately $100 to $175.
BreastScreen Australia
The BreastScreen Australia programme provides free breast
screening mammograms every second year for women 50-69
years of age. On request, women 40-49 years of age and women
70 years of age and older are able to attend for free screening
mammograms every second year (ref. note 7).
United Kingdom (UK) Recommendation
The UK’s National Institute for Health and Clinical Excellence
(NICE) Familial Breast Cancer Guideline recommends women
are offered yearly screening mammograms, if they:
- Are aged between 40-49 years of age
- Have an increased risk of developing breast cancer because of
their family history (any age) (ref. note 11)
Digital Mammography versus Conventional
Film Mammography
Some research by Skaane et al. (2007) shows digital
mammography has a significantly higher cancer detection rate
than conventional film mammography in a population-based
screening programme (Oslo, Norway) for women aged 45 – 69
years of age (ref. note 12). In a Canadian/USA 33 site screening programme,
a key finding is the accuracy of digital mammography is
significantly higher than that of conventional film mammography
in women:
- Under the age of 50 years
- With radiographically dense breasts
- Who are premenopausal or perimenopausal
(Pisano et al., 2005) (ref. note 13)
In New Zealand, digital mammography is an emerging
technology with nationwide screening implementation expected
within the next five years (ref. note 14). Currently, BreastScreen Aotearoa
has introduced digital mammography at BreastScreen Waitemata
Northland (Takapuna and Whangarei) and BreastScreen
Healthcare (Dunedin).
Conclusion
As there is sufficient evidence in the literature worldwide, the
Foundation recommends women - from the age of 40 to 49
years - have a yearly breast screening mammogram (either a
conventional film mammogram or a digital mammogram).
Reference Notes
1. Manitoba Breast Screening Program. Should women age 40 to 49 be screened? Fact Sheet: September 2005. Retrieved from Manitoba Breast Screening Program on 5 November 2007 http://
www.cancercare.mb.ca/MBSP/mbsp_professionals_40-49.shtml
2. Neave, L. et al. (2003, 24 October). The Auckland Breast Cancer Register: A special project of the Auckland Breast Cancer Study Group. The New Zealand Medical Journal, 116, 1184, p.9.
Retrieved from the New Zealand Medical Association website on 2 November 2007 http://www.nzma.org.nz/journal/116-1184/648/
3. Schuchter, L. Cancer at a young age more aggressive? Retrieved from Breastcancer .org on 2 November 2007 http://www.breastcancer.org/tips/life_quality/ask_expert/2006_04/question_14.jsp
4. Ministry of Health/National Screening Unit/BreastScreen Aotearoa (June 2007). More about breast screening and BreastScreen Aotearoa (booklet). pp. 18, 20. Author: NZ Ministry of Health.
5. Moss, S.M. et al. (2006). Effect of mammographic screening from age 40 years on breast cancer mortality at 10 years’ followup: A randomized controlled trial. The Lancet, 368, 2053-2060.
6. Ministry of Health/New Zealand Health Information Service (2007, August). Cancer: New Registrations and Deaths 2004. p.48. Wellington, New Zealand: Author
.
7. Australian Institute of Health and Welfare, Canberra (2006, October). Breast cancer in Australia: An overview, 2006. p.8, p.44 . Retrieved from the National Breast Cancer Centre, Australia
website on 6 August 2007 at http://www.nbcc.org.au/bestpractice/resources/BCR_breastcancerinaustra.pdf
8. The Royal New Zealand College of General Practitioners (1999). Guidelines for Primary Care Providers: Early Detection of Breast Cancer. p. 41. Wellington, New Zealand: Author.
9. Tabar, L., Yen, M.F., Vitak, B., Chen, HH.T., Smith, R.A., & Duffy, S. W. (2003, 26 April). Mammography service screening and mortality in breast cancer patients: 20-year follow-up before
and after introduction of screening. The Lancet, 361, 9367, 26 April 2003, 1405-1410. Retrieved from The Lancet website on 7 August 2007 at http://www.thelancet.com/search/results?search_
mode=cluster&search_cluster=thelancet&search_text1=Tabar+laszlo&x=6&y=11
10. Moore, Helen (2007, June). Breast Imaging. Presentation delivered at The General Practice Continuing Medical Education Conference, Rotorua, New Zealand on 15 June 2007.
11. Cancerbackup website, U.K. Breast and ovarian cancer risks/Breast Screening. Retrieved from the Cancerbackup website on 10 August 2007 at http://www.cancerbackup.org.uk/Aboutcancer/Genetics/Cancergenetics/Breastovariancancer
12. Skaane, P., Hofvind, S., & Skjennald, A. (2007, Sept). Randomized trial of screen-film versus full-field digital mammography with soft-copy reading in a population-based screening program:
Follow-up and final results of Oslo11 study. Radiology, 244, 3, 708-717.
13. Pisano, E.D. et al. (2005, Oct 27). Diagnostic performance of digital versus film mammography for breast cancer screening. The New England Journal of Medicine, 353, 1773-1783. Retrieved
from The New England Journal of Medicine website on 25 February 2008 at http://content.nejm.org/cgi/content/full/353/17/1773
14. National Screening Unit, Ministry of Health, New Zealand (2007, Nov). Statement on the use of digital mammography in the national breast screening programme, BreastScreen Aotearoa.
Retrieved from The National Screening Unit website on 9 March 2008 at http://www.nsu.govt.nz/Files/Statement_on_the_Use_of_Digital Mammography.pdf
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