CHECKING UP ON CANCER

March 02, 2025

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ANNUAL medical check-ups are a health habit that many believe can detect early signs of various illnesses, including cancer.

But are these check-ups enough to identify cancer in its early stages?

According to consultant clinical oncologist Dr Tan Chih Kiang, with cancer being a complex group of diseases, assessing the effectiveness of regular check-ups as a cancer screening tool requires understanding what these exams entail and how they relate to cancer detection.

For effective cancer screening, it’s essential to go beyond the annual check-up and follow the screening guidelines for specific cancer types.

“The usual medical check-ups are geared towards detecting diseases such as heart disease, diabetes and high blood pressure.

“In most check-up packages, there’s nothing much on cancer detection or screening, except for tumour markers. And even then, most tumour markers are not really specific,” says Dr Tan.

Cancer screening vs general check-ups

A standard annual check-up usually includes an assessment of one’s medical history, a physical examination and routine blood tests.

This may cover basic markers of health like blood pressure, cholesterol levels, blood glucose and a full blood count.

However, standard check-ups generally do not include specific cancer screening tests unless there is an identified need based on symptoms, risk factors or age.

“Many people are under the false impression that if their medical check-up gives them a clean bill of health, that means they are free of cancer too, especially when their tumour markers are all normal.

But in actual fact, this may not necessarily be the case.

“We can see patients come in with cancer six months after their medical check-up indicated they were in good health.

“Tumour markers alone are not an accurate tool to diagnose cancer. The sensitivity of such tests is even lower,” notes Dr Tan.

Someone can have cancer and their tumour markers may be completely normal, he adds.

While annual check-ups play an important role in overall health maintenance, they are not a substitute for targeted cancer screenings, advises Dr Tan.

“Sometimes, the tumour marker may be slightly above normal, but the patient doesn’t have cancer.

“Tumour markers are not a very sensitive test to screen for cancer itself, except for one tumour marker – PSA (prostate specific antigen). This tumour marker is very specific for prostate cancer,” he reveals.

“Tumour markers such as CEA, CA 19-9, CA 125, AFP, HCG – all these are not specific for cancer.

“Take the example of a lady with slightly elevated levels of CA 125.

“She might have that because she has just menstruated, or she might have a gynaecological condition that has raised her CA 125 levels.”

Dr Tan adds that there are also many cancers that are not associated with elevated levels of tumour markers.

In all instances, cancer screenings are more targeted and vary by cancer type.

For example, mammograms screen for breast cancer, Pap smears for cervical cancer and colonoscopies for colon cancer.

Each screening test is specific to a certain age group, gender or individual risk factors, and they are usually not part of a routine annual exam.

General check-ups often overlook these specialised screenings unless a patient proactively requests them or has clear symptoms. As such, relying solely on regular check-ups can lead to missed opportunities for early cancer detection.

When are specific cancer screenings necessary?

There are many different types of cancer. However, according to Dr Tan, there are only a few cancers in which screening tools or tests are available.

“For us to actually use a test or tests as a screening tool, the test must be relatively cheap, and be quite sensitive and specific to detect the cancer reliably.

“Not all tests fulfil such criteria, hence only a few reliable screening tests are available for cancer thus far,” he observes.

Specific cancer screenings are recommended for individuals based on age, lifestyle, family history and certain risk factors.

For instance:

> Breast cancer: Women over 40 are often advised to undergo regular mammograms.

Women with risk factors, such as family history of breast cancer, are encouraged to go for screening at a younger age – usually 10 years younger than the age the breast cancer sufferer was first diagnosed.

> Colon cancer: Faecal occult blood test (FOBT) and colonoscopy screening are typically recommended for those above 50.

If there’s a family history of colon cancer, then the test should be done at a much younger age.

> Cervical cancer: Regular Pap smears are recommended for women who are married or have had sexual intercourse. > Lung cancer: High-risk individuals, such as heavy smokers over the age of 50, may benefit from low-dose CT scans.

> Prostate cancer: PSA tumour marker is recommended for men aged 50 years and above.

Each of these screening tools has been proven effective for its specific cancer type, and they are best performed on a schedule suited to the individual’s risk profile. This approach is more efficient than relying on annual check-ups alone.

For some cancers, genetic testing is available. “Take the example of breast cancer,” says Dr Tan.

“If a breast cancer patient is found to have the BRCA gene associated with breast cancer, her family members could be tested too if they wanted to see if they are a carrier for the gene as well.”

According to him, genetic and environmental factors can both play a role in cancer occurrence.

“Most of the time, it’s a multi- factorial phenomenon – genes, advancing age, stress, poor diet, air pollution, sedentary lifestyle.

“We are not yet able to quantify how much of a role these factors play in cancer, just that they have an effect.”

Why annual check-ups are still valuable

Even though annual check-ups may not catch all cancers early, they are still valuable for maintaining overall health.

They provide an opportunity to detect other underlying issues, manage chronic conditions, and encourage lifestyle modifications that can lower cancer risk, such as quitting smoking, reducing alcohol intake and maintaining a healthy weight.

Regular discussions with a healthcare provider can also help identify when cancer screenings should be incorporated into one’s routine.

“There’s also a new diagnostic test called MCED (multi-cancer early detection).

“A blood sample is taken to look for cancer cell DNA.

“They have found that in some patients, they are able to detect the cancer way earlier, before any symptoms, and sometimes, even before the cancer forms any lumps or mass in the body.

“However, whether this test is good enough to be offered as a screening tool, the jury is still out.

“For one, the test is very expensive. And it’s not totally reliable.

“The patient may have cancer, but the test may not pick it up.

“Conversely, the patient may not have cancer, but the test says otherwise.

“Studies are currently being conducted to assess whether this test can be used as a screening tool,” reveals Dr Tan.

The importance of awareness and proactive screening

Cancer is a complex disease with various types and risk factors, and early detection often depends on more than just a once-a-year check-up.

Knowing one’s risk factors, recognising symptoms and communicating with the healthcare provider are essential steps.

By being proactive, individuals can work with their doctors to set up a screening plan that fits their unique health profile.

While annual check-ups play an important role in overall health maintenance, they are not a substitute for targeted cancer screenings, advises Dr Tan.

“Cancer detection requires specialised tests tailored to the individual’s risk factors and age.

“For effective cancer screening, it’s essential to go beyond the annual check-up and follow the screening guidelines for specific cancer types,” he exhorts.

This proactive approach offers the best chance of catching cancer early, improving treatment outcomes, and potentially saving lives.