A New Frontier in Preventative Healthcare

Precision medicine is elevating preventative healthcare by offering a nuanced understanding of individual disease risk and opening the door to novel methods of screening.

In 2018, a person diagnosed with breast cancer in Singapore had a 60% greater likelihood of surviving than a person diagnosed 40 years earlier. Despite the number of breast cancer cases more than doubling during the same period, the prognosis for breast cancer are now much better.

A major reason driving higher survival rates is because breast cancers in Singapore are increasingly being diagnosed in their early stages: as many as 70% of those breast cancer cases in 2018 were diagnosed at Stage I and II. This is a clear case of how preventative healthcare strategies like screening, or timely detection of diseases, can potentially save thousands of lives when applied to populations.

Prevention is better than cure

At its core, preventative healthcare involves identifying individuals who may be at risk of diseases that can be avoided through lifestyle changes or other preventive measures. The concept is divided into three categories: primary, secondary and tertiary prevention. Primary prevention aims to empower communities to take charge of their own health and prevent diseases before they even develop. This may be achieved through vaccination programmes or health promotion strategies such as Singapore’s National Steps Challenge, which motivated 1.3 million people aged 17 years or older to live more active lifestyles.

The goal of secondary prevention, on the other hand, is to detect disease as early as possible—ideally before the onset of symptoms—through screening strategies such as the Screen for Life programme. Finally, tertiary prevention seeks to reduce the severity and progression of a disease after its onset by using measures such as chemotherapy and other therapeutic treatments.

Although its outcomes are typically “invisible” compared to those of curative interventions, preventative healthcare was identified by Singapore’s Ministry of Health as a powerful tool to tackle emerging challenges like the country’s ageing population. In fact, “prevention is better than cure” was the mantra of the National Healthcare Plan (NHP) in 1983. Today, the Ministry of Health continues to invest in the strategy, having allocated $720 million to preventative healthcare in 2021.

Enhancing prevention with precision

Alongside the environment, our genes—specifically the mutations found in our DNA and their combinations—are the biggest determinants of our risk of diseases. Therefore, understanding every individual’s genetics could take the prevention strategies several notches higher by helping predict disease earlier and diagnose them more accurately.

This is one of the promises of precision medicine, which factors in variations in genetics, lifestyle and environment to offer diagnosis and treatment better tailored to specific patient groups. Like many countries around the world, Singapore has set up an action plan in the form of its National Precision Medicine (NPM) programme to harness the potential of precision medicine.

Phase I of the ten-year programme, which launched in 2017, saw the completion of the world’s largest genetics database on multi-ethnic Asian individuals. The 10,000-person-large repository will serve as a reference for identifying genetic variants that may be linked to disease risk—findings that could expand the types of diseases that can be detected early and inspire the development of new screening tools.

One such emerging method is to use microRNA (miRNA)—short pieces of RNA that are involved in turning genes on and off—as indicators of complex diseases such as cancer and stroke. Just as glucose levels are measured to indicate diabetes risk, measuring the expression levels of different disease-specific miRNAs could be a quick and inexpensive way to determine a person’s risk of developing that disease.

Taking it to the clinic

To pass on the benefits of precision medicine to patients, the crucial next step is to take the technology from the laboratory to the clinic—a major goal of Phase II of the NPM, which began in 2021. Clinical partners across Singapore have already begun piloting precision medicine programs, including at the National University of Singapore (NUS)’s Centre for Personalised and Precision Health and DUKE-NUS’s Institute of Precision Medicine (PRISM). At the same time, the use of miRNA as biomarkers for early disease detection is catching up. Until recently, miRNA-based assays were largely used for diagnosis, prognosis and understanding a patient’s response to particular therapeutics and their use for screening is currently confined to a small number of clinical laboratories.

But new national standards published by Singaporean researchers in 2020 to guide the design, development and evaluation of miRNA-based assays are already leading to the development of commercial “point-of-care” testing devices. Validated tests for gastric and lung cancers and even multiple cancers at once are nearing commercial availability.

Bringing the reality of precision medicine to Singapore is a long-term strategy, and NPM is steadily moving toward that goal. As researchers continue to gain understanding of the genetic basis of specific diseases and clinicians apply that knowledge in their clinical practice, they will be better equipped to catch more ailments earlier, giving the public a better chance of living longer, healthier lives.

References: NIL