Taking Breast Cancer Screening Beyond Standard Guidelines

Women make up over half the population in Singapore. Of those aged 50 to 69, over 94% know about breast cancer screening. Yet—less than 40% of this age group had gone for mammography in the last two years.[1] Is it any wonder why breast cancer remains the leading cause of cancer deaths[2] among women?_

Truth is—breast cancer is not a death sentence if it is discovered and treated early. The five-year survival rates for women diagnosed with Stage 1 and 2 breast cancer are 90% and 80% respectively. This dips to 66% for a Stage 3 diagnosis and plummets to 25% for Stage 4.[3] It should also be noted that early-stage breast cancers usually require less aggressive treatment, offer more treatment options—instead of mastectomy—and lower risk of relapse.

Dr Li Jingmei, Group Leader, A*STAR’s Genome Institute of Singapore (GIS) said, “What’s interesting is that women know the importance of breast cancer screening and where they can go to get screened. But the attendance for breast cancer screening is significantly less than that for chronic illnesses such as diabetes and cardiovascular diseases. Why doesn’t awareness translate into positive outcomes? What is the missing link? We are trying to answer these questions in the BREAst screening Tailored for Her (BREATHE) study.”

Standard Guidelines for Breast Cancer Screening

Worldwide, mammography screening recommendations are age-based—and these guidelines have largely remained unchanged for the past four decades. In Singapore, the Ministry of Health Clinical Practice Guidelines 1/2010 recommends that average risk, asymptomatic women aged between 50 to 69 to do a mammogram every two years. And for women between 40 to 49 years old, they should first consult a doctor on the benefits, limitations, and potential harms of mammograms before making an informed decision.[4]

Associate Professor Mikael Hartman, Department of Surgery, National University Hospital, explained, “At the moment, conversations around breast cancer screening are mostly determined by responses to these two questions: ‘Are you a woman?’ and ‘Are you over the age of 50?’ If your answers are ‘yes’ to both, then you should go do your mammogram every two years. For women below 50, unless you are at very high risk with BRCA1/BRCA2 gene mutations or similar, factors such as your risk profile, your breast density are not really being considered, etc.”

Dr Li said, “Additionally, the advice for women between 40 to 49 is to consult their doctors. But how does that consultation look like? What questions should one ask? This could be made clearer.”

Dr Wang Yi, Assistant Professor, Saw Swee Hock School of Public Health, National University of Singapore shared, “Research shows that the associated survival benefit is much higher among younger women.[5] Hence it is potentially economical to screen women at younger ages. The problem is—recommendations on early screening and diagnosis strategies are lacking in Asia[6].”

Tailored Approach to Breast Cancer Screening

Advantages of breast cancer screening are not lost to the Singapore Government. In a bid to capture the long-term benefits of reduction in breast cancer mortality at the population level, a national mammography screening programme (BreastScreen Singapore) was launched in 2002 to raise public awareness based on the prevailing standard guidelines.

A/Prof Hartman said, “While these guidelines are very clear, we will do well to remember that about one in three cancer cases are diagnosed before the age of 50. That means those under 50 are going to present themselves only when they have lumps or symptomatic presentations. Typically, those who are younger than 40—and even 50—do not participate in mammographic screening because there is no evidence that they should. This results in missed opportunities for early intervention.”

 Under the current age-based screening paradigm, approximately 30% of diagnosed breast cancer cases in Singapore are women of a younger age than the recommended screening age by the national guidelines[7]. A/Prof Hartman said, “Of course, we can simply ask everyone to go for screening. We can then pick up more cancers earlier. But what does that translate to from the economic perspective? Or how else can we encourage screening participation so that it saves lives, doesn’t burden the healthcare system, and is affordable to the nation? That is where the modelling work that Dr Wang Yi is doing, should provide some answers.

“We think if we use smarter ways to assess risk and share it with women, they would be willing to act on that risk by becoming proactive participants in screening. But it is a fine balance—what should we communicate, and how do we do that so that they would find it meaningful without feeling overly anxious? We are still in the midst of refining these. We are also trying to learn from the experiences of the cardiovascular teams who have significantly higher screening attendance—according to the National Population Health Surveys.”

In the Making: From Age-Based to Risk-Based

Dr Li added, “Early results do suggest that we are on the right track with BREATHE. Risk-based recommendations work better than general ones. However, we are still calibrating what a breast cancer risk report should look like—more information, less information, pictures, no pictures, with video, without video, etc.”

Dr Wang weighed in, “Through these findings from Dr Li and A/Prof Hartman, we are exploring how we can apply these technologies at scale in the clinical practice at the nationwide level—like how much would it cost and what kind of resources are needed?

“Before we can answer these though, we need to first decide who is in what risk category. The more we classify people into high risk, the more cancers we can prevent but it will be costlier to implement the programme. But it can also translate to cost savings in the long run. So it is all about getting the balance right.”

A/Prof Hartman concluded, “For BREATHE to be successful, we envision that the programme will eventually be rolled out to the community. The implication is that general practitioners and polyclinics need to be prepared to conduct these dialogues. Alternatively, can we find digital solutions so that women can assess their risk using electronic means, and do their own buccal swabs to extract DNA samples for analysis? We do not have all the solutions yet—but we are working hard to transform breast cancer screening in Singapore with BREATHE.”

Read more about the BREATHE programme here.

This project is supported by the National Research Foundation, Singapore, through the Singapore Ministry of Health’s National Medical Research Council and the Precision Health Research, Singapore (PRECISE), under PRECISE’s Clinical Implementation Pilot grant scheme.

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[1] Epidemiology & Disease Control Division and Policy, Research & Surveillance Group Ministry of Health and Health Promotion Board, Singapore, Singapore. National Population Health Survey 2019.

https://www.moh.gov.sg/docs/librariesprovider5/default-document-library/nphs-2019-survey-report.pdf

[2] National Registry of Diseases Office Ministry of Health and Health Promotion Board, Singapore Cancer Registry Annual Report 2020. https://www.nrdo.gov.sg/docs/librariesprovider3/default-document-library/scr-2020-annual-report_web-release.pdf?sfvrsn=e0a73b99_0

[3] Singapore Cancer Registry 50th Anniversary Monograph – Appendices.pdf, Appendix E: Relative and Observed Survival By Sex, Period, Site and Age Group, 1968 -2017

[4] Cancer Screening, MOH Clinical Practice Guidelines 1/2010, Ministry of Health. https://www.moh.gov.sg/docs/librariesprovider4/guidelines/cpg_cancer-screening.pdf

[5] Jansen JT, Zoetelief J. Assessment of lifetime gained as a result of mammographic breast cancer screening using a computer model. Br J Radiol. 1997;70(834):619-28.

[6] Yuniar P, Robinson S, Moorin R, Norman R. Economic evaluation of breast cancer early detection strategies in Asia: a systematic review. Value in Health Regional Issues. 2020 May 1;21:252-63.

[7] Ho PJ, Lau HSH, Ho WK, Wong FY, Yang Q, Tan KW, et al. Incidence of breast cancer attributable to breast density, modifiable and non-modifiable breast cancer risk factors in Singapore. Sci Rep. 2020;10(1):503. doi: 10.1038/s41598-019-57341-7