Cancer Screening: What To Expect & How To Do It Right?

 In Cancer

Cancer screening is an important tool in preventive medicine to detect cancer early, including when the patient has not developed any symptoms. The objective is to catch cancer at an early stage before it has spread, which will increase the chance of curing it. The screening often involves a discussion with the doctor or oncologist about risk factors, such as related medical conditions, family history and lifestyle. This will help you better understand your risk of developing cancer and measures you can take to lower your risks, regardless of whether cancer is detected. 

So if everyone goes for cancer screening regularly, why do we still have cancer cases diagnosed in advanced stages? The answer is worth an article, as cancer is a complex disease with over 100 different types manifesting in distinct ways. Getting the most out of cancer screening requires the right understanding of its advantages and disadvantages. 

In this article, we discuss cancer screening, its benefits and limitations, recommended screening by cancer types, who should do it and how to do it right. We also address several common myths about cancer screening, to ensure our readers can make the most of cancer screening for their optimal health and well-being.  

What Is Cancer Screening?

Screening tests are a group of medical tests that are performed to detect diseases at any early stage before symptoms appear. Similarly, cancer screening is done for healthy individuals without any signs and symptoms of cancer, for the purpose of early detection of cancer. 

Catching cancer early, ideally before it has spread, helps to improve treatment outcome, reduce treatment time and cost, and increase survival rate. For instance, a study shows that breast cancer screening using mammograms brings about a reduction of 25% in the rate of developing advanced breast cancer and of 41% in 10-year mortality rate. 

Cancer screening is recommended to people who are at a significant risk of developing cancer because of their gender, age, family history, and other risk factors. However, it is important to note that cancer screening does not always mean you have cancer. Even if a screening shows signs of cancer, the findings of a screening test need to be confirmed through further investigations. Cancer cannot be diagnosed by cancer screening alone.

Why Is Cancer Screening Important?

One of the most important benefits of cancer screening is early detection, before a person experiences symptoms of the disease. Very often, by the time obvious symptoms of cancer are present, cancer has progressed to an advanced stage and/or has spread from its original location to other parts of the body, making treatment more difficult and less effective. 

In the scenario cancer screening shows signs of cancer, which should be confirmed later during cancer diagnosis, catching cancer early through cancer screening has the following advantages: 

  • Improve treatment outcome: Cancer screening allows the earlier detection of cancer before it spreads in the nearby tissues, making the treatment more effective with better outcomes. 
  • Reduce treatment costs and recovery time: Early detection by cancer screening results in reduced treatment costs and less use of light therapy and other chemicals. Early treatment also helps you recover faster. 
  • Increase the chance of survival: Cancer screening is known to significantly lower death rate from cervical cancer, breast cancer, bowel cancer, and abdominal aortic aneurysms. As the slogan goes, “Early detection saves lives”.

In the scenario no cancer is detected, the screening is not wasteful. In fact, it offers the below benefits:

  • Peace of mind: It may be a few anxious days waiting for the screening results, but it will be worthwhile for you and your loved ones to have the assurance that cancer is not detected, and that you have done the best you can to manage your cancer risk. 
  • Detection of precancerous changes in the body: Another reason why cancer screening is important is that it can find changes in the body induced by cancer. These changes, if left undetected, can become cancer. 

Despite the advantages cancer screening offers, it is a personal choice whether or not to go through the exercise. Some people may find it stressful, costly or troublesome. To make the best decision, it is important to have the right understanding and expectations of what cancer screening can and cannot do for you and your loved ones. Read on as we debunk the common myths about cancer screening.

Myths And Facts About Cancer Screening

The following are some misconceptions that are commonly asked and need to be cleared.

Myth 1: Everyone should scan for all types of cancer to be sure of their risk.

This is a misconception for two reasons. The first thing that needs to be cleared is that cancer screening still has not been developed for all cancer types. There is no known silver bullet that can detect all kinds of cancer. Each cancer test is specific to a cancer type. If you are at risk of developing a type of cancer, you should consult the doctor to screen for that particular cancer type. Let’s take the example of a woman who has a family history of breast cancer. She may go for breast cancer screening to detect any gene mutations associated with breast cancer, such as BRCA1 or BRCA2. She may also be recommended to go for regular mammograms earlier than the commonly recommended age of 40. 

Secondly, among available cancer tests, sensitivity and efficacy varies. There are also certain risks associated with the screening method, such as complications risk associated with biopsy. Cancer tests therefore are often recommended for informed patients with certain risk profiles. For instance, prostate cancer screening tests are available, but not recommended for all men above 50 years old. A variety of factors, including risk factors of the individuals, the side effects of the tests, the risk of false positive and overtreatment, must be considered by the patient and his doctor or oncologist to determine whether screening for prostate cancer is warranted or not. 

Myth 2: Cancer screening can guarantee early detection of cancer, or that you are free from cancer.

As advanced as medical tests are nowadays, they are not 100% accurate. Available tests, however established, come with a margin of error, including false positive and false negative. Sometimes, cancer screening may detect non-cancerous growths, such as non-cancerous polyps in the case of colon cancers, prompting unnecessary investigation or even treatment. Other times, a check-up may miss or overlook cancer, resulting in delayed diagnosis. 

But this does not mean that cancer screenings are not effective. Regular cancer screening tests still offer us the best opportunity to detect early signs of cancer. By undertaking suitable check-ups, we take personal health matters in our hands in the best way possible. 

Myth 3: An MRI or CT scan is the best way to screen cancer, because it can see inside the body and detect all cancer cells. 

It is true that MRI (magnetic resonance imaging) and CT (computed tomography) serve a great benefit to identify, locate and stage cancer. But there are certain drawbacks to these imaging methods, including costs, which make them more commonly used in diagnosis rather than in screening. Some types of cancers like breast cancer are not detectable with MRI and CT. In such cases, other tests are performed, such as mammograms for breast cancer. 

The guiding principle is that the benefits of a test should outweigh its risks and cost burden to the individual. Before requesting a test, patients should always consult their doctor or oncologist to understand the full picture and make an informed decision. 

Myth 4: There is no need for cancer screening until the age of 40. 

It is true that cancer risk increases with age. But not all cancer cases are detected after midlife. 5% of breast cancer is diagnosed before the age of 40, as an example. Additionally, the average cancer risk of the general population may not apply to you, due to your individual genetics, lifestyle habits and environmental exposure. 

It is crucial to know your own risk profile and seek advice from a doctor or oncologist of when to go for which screening and how often. 

Common Cancer Screening Test Types

General health check-up is a great starting point to identify diseases or abnormalities. The result helps to rule out many factors and direct doctors to diseases or risks that otherwise go unnoticed in the body, including cancer. You may opt to do cancer screening as part of the general health screening, or as a separate check-up with a specialist or oncologist, depending on your personal preference and risk assessment.

Following are the most common tests used to scan for cancer in the body:

  • Physical Examination: These are done by checking for any unusual lumps and outgrowth in any part of the body. 
  • Medical Tests: Laboratory tests like urine, blood, sputum, and tissue samples are taken to look out for any abnormality.
  • Imaging: This is done to obtain 3D images of different parts of the body for detecting any abnormality. Imaging tests include ultrasound scan, X-ray, CT scan, MRI scan.
  • Genetic Tests: These are performed to determine any unusual change in the genome. These help to identify any genetic or unique disease. An example is the BRCA gene test for hereditary breast and ovarian cancer.

Recommended Cancer Screening By Cancer Types

In general, recommendations for cancer screening are often based on reliability and accessibility of the screening test, and the prevalence of the cancer types. As discussed extensively above, the decision for cancer screening is best consulted with a doctor or oncologist. To help you better understand your risk factor and start the conversation with a doctor, below are a list of available cancer screening tests and associated risk factors for 4 of the leading cancer types in Singapore: breast cancer, cervical cancer (for women), prostate cancer (for men), and  colorectal cancer (for all). 

1. Breast Cancer:

Types of Screening Tests: 

  • Mammography: Mammography is a proven screening test for breast cancer. These help a great deal when it comes to locating small tumors in breasts or other breast abnormalities. 
  • Self-Breasts Examination: At-home thorough checking to see whether there is a lump or an unusual outgrowth on the breasts. 
  • Clinical Examination: Doctors will run physical tests to see whether there is an abnormality of breasts of any kind. 
  • Magnetic Resonance Imaging (MRI): This helps locate a detailed image of the breasts for the detection of tumor or abnormality.

Risk Factors:

  • Age: 95% of breast cancer diagnoses happen after the age of 40. The risk increases with the age of the patient. Screening tests for breast cancer are therefore usually recommended after the age of 40, unless the patient is at higher risk due to other factors, as listed below. 
  • Family History: A family history of breast cancer puts the individuals at higher risk. Such patients can be recommended to have their risk checked via mammography or BRCA mutation gene by the age of 30.
  • Lifestyle: Although unhealthy lifestyle is linked to cancer in general, it is not specific to breast cancer. Research links lifestyle factors such as smoking, excessive alcohol consumption, even chronic stress with an increased risk for cancer.

2. Cervical Cancer: 

Types of Screening Tests: 

  • Human papillomavirus (HPV) testing: HPV is done by taking cell samples from the cervix of the females to test for the presence of the virus. 
  • Pap test: This is done by collecting cell samples outside the woman’s cervix which are then tested by a pathologist.

Risk Factors:

  • History of an oncogenic HPV infection: The link between a number of strains of HPV with cervical cancer is well documented
  • Age: Younger women are less likely to have cervical cancer but the risk increases between 20s and 30s. 
  • Lifestyle: Smoking and excessive use of birth control pills are believed to increase the risks of cervical cancer. 

3. Colorectal (colon) cancer:

Types of Screening Tests:

  • Colonoscopy: During a colonoscopy, a flexible tube is inserted into the rectum for the doctor to look inside the entire colon for tumors or any kind or polyps.
  • Sigmoidoscopy: This is similar to a colonoscopy, but sigmoidoscopy only examines the lower colon. The tube that goes inside the colon is called a sigmoidoscope, often of larger size than the one used in a colonoscopy. 
  • Fecal Occult Blood Test (FBOT), and Faecal Immunochemical Test (FIT): These tests are run to detect blood in the stool and feces of the patient, which can serve as a major indication of polyps and tumors. They have the advantage of being non-invasive tests that can be easily done at home, compared to a scope. However, the drawback is their lower sensitivity. As part of the national health screening program, eligible Singaporeans and SPR can apply for the FIT test kit for free from Singapore Cancer Society.
  • Double Contrast Barium Enema: This is an X-ray examination of the rectum and colon region of the body. This is an alternative option for people who do not prefer colonoscopy.
  • Stool DNA test: This is a stool analysis test to check for DNA changes in the cells, which can indicate tumors in the colon.  

Risk Factors: 

  • Age: There are few chances of colon cancer in young people but mostly the risk is higher in older aged people.
  • Family history: People with a family history of colon cancer have greater chances. 

4. Prostate cancer:

Prostate cancers are screened by digital rectal examination (DRE) where the doctor places a gloved finger inside the patient’s rectum in different angles to look out for any abnormalities.

Another test is Prostate Specific Antigen (PSA), which is done by withdrawing blood and testing it for higher levels of PSA (a blood substance). Higher levels might indicate cancer. 

Though available, both of the tests are currently not recommended for the general public. Patients who wish to screen for prostate cancer are recommended to consult their oncologist before ordering the test. 

Molecular / DNA based Cancer Screening Tests Are Available

A blood test called GASTROClearTM is a qPCR-based diagnostic test kit that measures 12 microRNA biomarkers linked to gastric cancer and calculates a cancer risk score for each patient using a proprietary algorithm that has been clinically validated. It is the world’s first such test approved for use in Singapore. Do consult the oncologist.

Lucence’s NPC GOLD™ is a cancer screening blood test with a focus on nose cancer by analysing the blood samples. This advanced blood test can diagnose early stage nasopharyngeal cancer before symptoms show. The test detects a DNA fragment of the Epstein-Barr virus called BamHI-W even if they are in minute amounts. This virus is found in almost all patients with nasopharyngeal cancer. Do ask the oncologist about this screening test.

Epi proColon is the first and only FDA-approved blood test colorectal cancer screening for people who are unwilling or unable to be screened by recommended methods detailed above. Do contact the oncologist to enquire about it.

Family History of Cancer and Genetic Screening for Inherited Cancer Syndromes

Frequently we have family members who have been diagnosed with cancer and we may wonder what our risks are. For those who inherited cancer pre-disposing genes, the type of cancer screening tests and frequency changes to reflect the heightened risk profile. Do consult an oncologist today about it for proper genetic counselling and assessment. The genetic screening procedure is a simple blood test. 

The Bottom Line

Medical advancements in cancer screening technology have made remarkable improvements in detecting cancer early and saving lives. Cancer check-ups have empowered many to take health matters in their hands and make it treatable for what was once a terminal disease. 

We hope the article provides you with the practical knowledge about cancer screening and how to take advantage of available tests for your health and well-being. Reach out to us for a private consultation of your personal cancer risk profile and the type of cancer tests recommended just for you. 

Dr Donald Poon, Medical Oncologist

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