Just a Thought

Controversies about breast cancer screening: what should we believe?

The need for world wide reassessment of mammographic screening practice was precipitated by a Cochrane Review for breast cancer screen policies [1].The Review stated that as women age, the benefit of screening—reduced risk of death from breast cancer—is increasingly offset by the other causes of death. Also, while the benefit is delayed, the hazards of screening—tests for false-positive x-ray films, discomfort and anxiety—are far more immediate. Thus, with increasing age, the data show a further decline in benefit, which is exaggerated when adjustment is made for quality-of-life factors [2].

It is the younger women who have the most to gain from screening—those who attend for screening are more likely to be non-smokers and to be in good health already. Those who really need screening may not be getting it; and those who perhaps don't need it - the older women - are getting too much screening. Older women are more likely to die of diseases other than cancer.

Therefore, women, clinicians and policy makers should consider these findings carefully when they decide whether or not to attend or support screening programs [3].

In considering Cochrane’s review, Olsen and Gøtzsche (2001) commented that the survival benefit of mass screening for breast cancer and the evidence for breast cancer mortality is inconclusive [4].

The efficacy of breast cancer screening has been demonstrated in randomised controlled trials (RCTs) and observational studies; thus, most organisations endorse regular mammography as an important part of preventive care. However, while it is true that screen-detected breast cancers are associated with reduced morbidity and mortality, the majority of women who participate in screening do not necessarily develop breast cancer in their lifetime. Also, breast cancer screening can lead to harm in some women who undergo biopsy for abnormalities that are not breast cancer, as well as those who are over-treated for ductal carcinoma in situ (DCIS) that might have been non-progressive. Therefore, in addition to benefits, limitations of screening and harms associated with screening should be updated in a guideline [5].

Limitations of mammography and harms associated with screening
As is the case with any screening examination, the goal of breast cancer screening is to detect any hidden evidence of breast cancer in a population of women in which the great majority will not have breast cancer on the occasion of a regular examination, and the large majority will not develop breast cancer in their lifetime.

Although the efficacy of mammography has been demonstrated, it needs to be recognised that screening does not always achieve perfect sensitivity or specificity in women who undertake mammography. As such, the issue of adverse consequences for women who do and who do not have breast cancer has been a source of growing attention, and has become one of the core issues in recent debates about mammography. False negatives can be attributed to inherent technological limitations of mammography, quality assurance failures, and human error; false positives also can be attributed to these factors as well as to heightened medico-legal concerns over the consequence of missed cancers. Further, in some instances, a patient’s desire for definitive findings in the presence of a low-suspicion lesion also contributes to false positives. The consequences of these errors include missed cancers, with potentially worse prognosis, as well as anxiety and harms associated with interventions for benign or non-obligate precursor lesions.

This issue of limitations and harms is both important and complex, since mammography’s shortcomings are due to the interplay between host characteristics (age, risk, breast density, and tumor growth rates) and provider factors (technical limitations and quality assurance failures). Thus, theoretically, there is at least some level of limitations and harms that is inherent to breast cancer screening and unavoidable. Beyond this level are potential improvements in screening and reductions in harms that could be achieved through various technical and system-related interventions. This relationship between risk, benefit, limitations, and harms is complicated by the fact that not only is it multi-factorial, but also that individual women likely will weigh the benefits, limitations, and harms of screening differently depending on their age, values, and their understanding of the issues.

Trials of mammographic screening commenced in the 1960s and seven have been completed and reported. On the basis of these trials, which showed a reduction in mortality from breast cancer in screened women, mammographic screening recommendations have been drawn up (e.g. United States), and in several countries political decisions were made to institute national programs (e.g. United Kingdom, Australia and New Zealand).

Although clinical-trial methodology has improved in four decades, population-health intervention studies remain notoriously difficult to perform because of problems associated with large cohort numbers, the randomisation process and guaranteeing reliable stratification. It is not surprising that the seven, now old, trials can be criticised. However, not all would suggest ditching them and their conclusions on these grounds. The Cochrane Breast Cancer Editorial Group has not accepted the other conclusion of Olsen and Gøtzsche — that screening leads to more aggressive treatments — and has not included that section of their review in the Cochrane Library. Others reject Olsen and Gøtzsche's conclusions because they are based on all-cause mortality, which may be inappropriate in population studies.

In 2000, Gøtzsche and Olsen, publishing a "Cochrane Review" of the seven trials in the Lancet (7) reported that they found no reliable evidence that screening for breast cancer reduced mortality. However, this report did not fulfil the Cochrane Group protocol for such a review. Since then Gøtzsche and Olsen have worked with the Cochrane Breast Cancer Editorial Group, and in October 2001 part of their review was accepted and included in the Cochrane Library. Almost simultaneously, the Lancet published Gøtzsche and Olsen's review in full on its website, and a research letter in its printed journal with an editorial commentary criticising the Cochrane Breast Cancer Editorial Group for interference. The whole episode has drawn a flurry of criticism and counter-criticism [6].

In 2002, the American Cancer Society (ACS) convened an expert panel to review the existing early detection guidelines based on accumulated evidence. The terms of reference for the expert panel were to review recent evidence and develop recommendations regarding: (1) mammography; (2) physical examination; (3) screening of older women and women with co-morbid conditions; (4) screening high-risk women; and (5) screening with new technologies.

The expert panel reviewed literature related to breast cancer screening published between January 1997 and September 2002 in identified bibliographies using MEDLINE (National Library of Medicine), as well as personal files of panel members using new screening tests based on specified criteria and their unpublished manuscripts. The panel also held personal discussions and a series of conference calls.

Also in 2002, the 10th anniversary of Australia’s national breast screening program (1992-2002), Barratt et al (2002) conducted a study which highlighted the need for reassessment of breast screening policies. Barratt et al indicated the estimated benefit of screening women between 70–79 years to be about one-third to three-quarters that achieved in women aged 50–69 years. Further, the authors provided a rough estimate of the cost-effectiveness of screening older women and the wide range of cost estimates per quality-adjusted life-years saved (QALYS)) underlining their imprecise nature, but suggesting that mammographic screening of women aged 70–79 years is as cost-effective as screening the other group—women 40–49 years. However, they reminded us that the estimation of benefits, harms and costs would be improved with data from randomised trials in the appropriate age group—which unfortunately was still lacking [7][8].

There is limited data on the efficacy of screening mammography in women over the age of 69. Only one randomised controlled trial (RCT) included women older than 69. Published screening studies have concluded that the performance and effectiveness of mammography is at least as good, if not better, in women aged 70 and older compared with younger women. In the absence of more definitive data, groups that have issued screening guidelines have reached the same conclusion.

After all this, what should women believe, especially as the systematic review of Barratt et al suggests that screening for women over 70 years may be of some benefit (and as cost-effective as it is for those under 50 years), on the basis that screening is beneficial in women aged 50–69 years?.

Rationale and evidence
In 1999, 63.7% of women in the target age group (50–69 years) were screened in Victoria [9].Further, in view of Barratt et al estimates of benefits and costs per quality-adjusted life-years saved, it could be argued that money for screening older—or younger—women could be better spent on recruiting more women in the target group to achieve the desired 70% participation [10].

The size of the older population is growing exponentially. Persons over age 65 years represent approximately at lease one-fifth of the Australian population (20 million), and their numbers are expected to double in the next 20 years. Increasing numbers of women and their health care providers are faced with questions about whether and when to end breast cancer screening. They will be required to make judgments on the balance between the potential benefits of screening—reduction of breast cancer morbidity and mortality resulting from early detection—and potential harms, which among women with co-morbidity or limited longevity could cause suffering and diminished quality of life in remaining years without appreciable benefit. The balance of this equation shifts with chronological age, life expectancy, co-morbidity, and functional limitation.

Although incidence and mortality rates are higher in older women, the question of screening in this population must be considered in the context of competing risks of death from co-morbid conditions, limited longevity, and a woman’s overall health status. Screening decisions in older women should therefore be individualised by considering the potential benefits and risks of mammography in the context of current health status and estimated life expectancy. As long as a woman is in reasonably good health and would be a candidate for treatment, she should continue to be screened with mammography. However, if an individual has an estimated life expectancy of less than three to five years, severe functional limitations, and/or multiple or severe co-morbidities likely to limit life expectancy, it may be appropriate to consider cessation of screening.

Therefore, chronological age alone should not be the reason for the cessation of regular screening.

Current breast screening policy in NSW: a patient-centred approach

The Australian initiative of a person (or patient) centred-approach is based on the international model of how breast cancer care should be delivered—within a framework of lifestyle management and healthy ageing (health promotion, health education and self-care) [11[]12[]13].

The NSW health policy is based on international research standards that recommend breast screening for all 40+ citizens (women, as well as men who develop breast mass tissue—a condition called Gynecomastia). Given this research, NSW Health is engaged in extensive health education campaigns to inform citizens that all 40+ are eligible (and should opt) for breast screening. Further, that age groups 50-69 are actively recruited for screening as this cohort of individuals is proven to have the greatest mortality benefit.

Education and self-care are important components of a patient centred approach i.e. informed responsibility for one self. Therefore, the onus for self-care is placed on citizens in the age group of 40-49 and 70+ to discuss their family history and risk factors with their General Practitioners and to volunteer for breast screening. Appointments are offered on phone at 13 20 50 but these cohorts of age-groups are not actively recruited for breast screening.

The Breast Cancer Institute of NSW Health has in place a world class centre of excellence for the care of women and men with breast disease and those at risk of, or diagnosed with, breast cancer. This facility—a partnership with BreastScreen Greater Western Sydney and Westmead Hospital—exists at Cumberland Hospital. It offers a “one-stop-shop” that operates with mammography, ultrasound and pathology services, including BreastScreen assessment clinics.

This is the first major project to be completed by Western Sydney Health’s Women Information Network (WIN) Program. Over the next decade, the WIN Program will transform Westmead Hospital through a major redevelopment designed to pro

vide the kinds of health care services we will need for the decades ahead. Further information is available from Richard Tewson, Manager, Population Health Strategy, NSW BreastScreen, Cumberland Hospital, Phone: 02-8838 2100.

Some issues to consider
When consulting your GP, some issues to keep in mind are that the genetic and epidemiological studies include women who are known carriers of mutations in either of the two genes and have particularly high risks of breast and ovarian cancer. Although only laboratory testing can confirm that a woman carries a deleterious mutation in one of these genes, genetic and epidemiologic studies document several family history characteristics that suggest an increased risk of breast cancer [14]. These reflect the autosomal dominant mode of inheritance, and include:

Some clinical questions
Should we offer a patient routine breast cancer screening with mammography?

When considering whether to implement a screening test, several factors must be considered: (1) Does early diagnosis lead to improved survival or quality of life, or both? (2) Are early-diagnosed patients willing partners in the treatment strategy? (3) Are the time and energy it takes to confirm the diagnosis and provide lifelong care well spent? (4) Do the frequency and severity of the target disorder warrant this degree of effort and expenditure? [15].

Footnotes

  1. The Cochrane Collaboration, founded in 1993 and named after British epidemiologist, Archie Cochrane, is an international non-profit and independent organisation, dedicated to making up-to-date, accurate information about the effects of healthcare worldwide. It produces and disseminates systematic reviews of healthcare interventions and promotes the search for evidence in the form of clinical trials and other studies of interventions. The research reviews are published in quarterly database of The Cochrane Libraryhttp://www.cochrane.org/docs/descrip.htm
  2. Cochrane Collaboration Topic: Breast Cancer. Latest reviews to 22 Jul 2005, are available at http://www.cochrane.org/reviews/en/topics/52.html
  3. The Cochrane Database of Systematic Reviews 2001, Issue 4. Art. No.: CD001877. DOI: 10.1002/14651858.CD001877.
  4. Olsen O, Gøtzsche PC. Cochrane review on screening for breast cancer with mammography. Lancet 2001; 358: 1340-1342.
  5. Olsen O, Gøtzsche PC. Screening for breast cancer with mammography. The Cochrane Database of Systematic Reviews 2001, Issue 4. Art. No.: CD001877. DOI: 10.1002/14651858.CD001877.
  6. Gøtzsche PC, Olsen O. Is screening for breast cancer with mammography justifiable? Lancet 2000; 355: 129-134.
  7. Barratt A, Irwig L, Glasziou P, et al. Benefits, harms and costs of screening mammography in women 70 years and over: a systematic review. Med J Aust 2002; 176: 266-271.
  8. Simes J, Wilcken N, Brunswick C, et al. Screening mammography — setting the record straight. Lancet 2002; 359: 439-440.
  9. BreastScreen Victoria 1999 Annual Statistical Report. Melbourne: BreastScreen Victoria , 2001.
  10. Giles GG. Canstat: cancer in Victoria 1999. Melbourne, Anti-Cancer Council of Victoria , August 2001.
  11. Tabar L, Yen Ming-Fang, Vitak B, Hsiu-Hsi Tony Chen, Smith RA, Duffy SW, 2003. Mammography service screening and mortality in breast cancer patients: 20-year follow-up before and after introduction of screening, Volume 361, Number 9367 (26 April 2003). 
  12. Hendrick RE, Smith RA, Rutledge JH, Smart CR, 1997.The benefits of screening: mammography in women aged 40-49-- a new meta-analysis of randomised controlled trials.  Monograph: National Cancer Institute 1997; 22: 87-92.
  13. See also The Cancer Council of NSW http://www.nswcc.org.au/
  14. Burnet K, Benson J, Earl H, Thornton H, Cox K, Purushotham AD. 2004. A survey of breast cancer patients' views on entry into several clinical studies. European Journal of Cancer Care ( England). 2004 Mar;3(1):32-5. PMID: 14961773 [PubMed - indexed for MEDLINE]
  15. Purushotham AD, Macmillan RD, Wishart GC, 2005. Advances in axillary surgery for breast cancer-time for a tailored approach, Cambridge Breast Unit, Addenbrookes Hospital, Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge CB2 2QQ, UK. European Journal of Surgical Oncology. [E-publication, ahead of print; 15 August 2005].

References

HEALTH SURVEY
(Issue: 26/08/05)
This section is linked to the Discussion Forum




Do you agree that all women under 40 years should have breast screening?.
1. Yes
2. No

Do you agree that breast screening for women over 70 is beneficial for their health and quality of life?
1. Yes
2. No

How much responsibility should women take for their personal health and initiate discussion with their GPs on matters such as preventive measures and screening including mammography?

Please write the number and comments on what influences your decisions and the choices you make.


Survey Disclaimer

Please keep in mind that this survey is for infotainment and is not conducted for scientific merit. We make no guarantess about accuracy of the result, other than reflect the preferences of our readers who participate in this survey.

If you have any questions or comments about the survey please email m.bhatia@mary.acu.edu.au

READER FEEDBACK

Industrial Relations Reform : Entreprise Bargaining
Do you know your early warning stress signals? (16 08 2005)

"Ranjit Bedi" ranbedi@hotmail.com
Thank you so very much for the information.Regards. Ran Bedi , NSA Parramatta

"Alan Greig" <ahgreig@bigpond.com>
The Australian Employee Ownership Association (AEOA) has recently up-graded its web-site to provide up-to-date news on policy developments and discussion on all aspects of the growth of broad-based employee ownership in this country. The website provides much research which shows a clear link between employee share ownership and improved corporate performance with regard to workplace mental health and enterprise bargaining

We would be particularly keen for you to consider placing the AEOA's website www.aeoa.org.au under on your "Useful Links" page an informing your colleagues about accessing this website for latest information. work-place change, industrial relations reform, employee participation, human resources management, remuneration planning and corporate performance, corporate social responsibility and accountability and local economic development. It is also important for those interested in broader participation in wealth creation, the more productive use of capital and embracing the culture of ownership and entrepreneurship in private businesses.

Thank you Alan, you are now linked with this website under Usefull Links at http://dlibrary.acu.edu.au/research/ageing/meeting_place/links.html /Ed.

"Luba" froadtap@travelnotes.every1.net
I saw your interesting information on the Australian Industrial Reform on the website. My name is Luba. I am a 28 year old from the Russian Federation. Please include me in your healthy ageing mailing list. Thank you.

"emma" emma@phfs.ngo.org.au
Just to let you all know that my email address will be changing as from the beginning September 2005 to phfsemma@bigpond.net.au . Please continue me on your mailing list. Regards, Parramatta/Holroyd Family Support Service.

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Monika Bhatia
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26 August 2005

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