Screening for Cancer
Key Takeaways
Cancer screening tests help to detect cancer in its early stages, when it’s significantly easier to treat.
It’s common for cancer not to cause any apparent symptoms in the early stages, so screening tests may be the only way to find cancer during this time.
Specific screening tests are recommended for people in specific groups. These may be based on factors like age, gender, family history, and other risk factors (such as smoking, alcohol consumption, or obesity).
Not all of the screening tests currently on the market have been shown to be accurate or beneficial. A doctor can advise you about which tests are recommended for you.
A positive result on a cancer screening test indicates possible cancer, but is usually not enough to diagnose cancer on its own. Further testing is generally needed to determine whether or not you have cancer.
The importance of going for cancer screening
Although many people think of going to the doctor only when they feel unwell, it’s also important to go regularly even when you feel healthy. This is known as a well check or a health screening. During a health screening visit, your doctor will look for signs that you may have a medical condition that requires treatment.
In addition, your doctor may recommend that you get screening tests. These tests may check for a few different health conditions, including cancer. Detecting cancer early makes it much easier to treat and increases the chances of achieving long-term cancer remission. When cancer is in its early stages, it often causes few or no obvious symptoms. Screening tests can pick up these early cancers, allowing them to be treated before they become more serious.
Cancer screening tests need to be ordered by a physician. They will be able to advise you on which tests would be beneficial for you. Not all of the screening tests currently on the market have been shown to be accurate or beneficial, so it’s important to have a medical professional determine which tests are recommended in your particular situation. They’ll also be able to interpret the results for you and make recommendations about the best next steps.
There are a variety of different cancer screening tests available. Specific tests are generally recommended for specific groups. This could be based on factors like age and gender, or it could be related to certain risk factors that increase your likelihood of developing a particular type of cancer.
Cancer stages
The stage of a cancer refers to how advanced the disease is. There are many different ways to describe cancer stages, and they differ somewhat for different types of cancer. One commonly used staging system is called the TNM system. For this system, cancer is assigned a number for each of these letters:
T stands for tumor, and refers to the size of the initial tumor and how extensively it has grown into nearby tissues.
N stands for nodes, and refers to the number of lymph nodes that the cancer has spread to.
M stands for metastasis, and refers to whether the cancer has spread to more distant parts of the body (away from where the cancer first arose).
Higher numbers indicate more advanced cancer. For example, T1 means that the tumor is relatively small and contained, while T4 means that it’s much larger and is spreading into the tissues around it.
In general, cancer is much easier to treat in the earlier stages. For example, cancer that has not yet spread to lymph nodes or more distant parts of the body may be able to be removed completely with surgery. Once the cancer has begun to spread through the lymphatic system or bloodstream, surgery can’t remove all of it, and it’s much more difficult to remove all of the cancer cells from the body. This is why the likelihood of long-term survival is generally significantly higher when cancer is treated in the early stages.
This is why cancer screening is important. By catching cancer while it’s in its earlier stages, there are more treatment options available, and it’s more likely that the treatment will be successful at removing the cancer and extending your life.
Risk factors for cancer
Although anyone can potentially get cancer, there are certain factors that raise the risk of particular types of cancer. Some of the most common risk factors include:
Age. Most types of cancer become more common as people get older. Cancer screening tests are often recommended only for people over a certain age, because the likelihood of cancer is higher in older people.
Family history. People who have multiple close relatives who have had a certain type of cancer may be more likely to develop that type of cancer themselves.
Smoking. More than 90% of lung cancer cases are caused by smoking, and smoking also increases the risk of a variety of other types of cancer.
Alcohol consumption. Drinking a lot of alcohol also increases the risk of several types of cancer, including liver, breast, and colorectal cancers.
Obesity. People who are very overweight have an increased risk of developing several types of cancer, including breast, pancreatic, liver, and kidney cancers.
Ultraviolet (UV) light exposure. People who are exposed to high levels of ultraviolet light, either from unprotected sun exposure or the use of tanning beds, have an increased risk of skin cancer.
Infections. People who are infected with certain viruses have an increased risk for certain types of cancer. For example, the hepatitis B and C viruses increase the risk of liver cancer. Certain strains of the HPV virus increase the risk of cervical cancer.
Types of tests that are used to diagnose cancer
There are a variety of different cancer screening tests available. In some cases, a physical examination may be able to detect signs of cancer. Laboratory tests that may be used include tests of blood or fecal samples or tests of samples of cells taken from particular areas of the body. There are also a variety of imaging tests that can be used to screen for cancer.
Physical Examination
When you visit your doctor for a health screening, they’ll perform a physical examination. This includes looking and feeling for signs that you might have cancer. Examples of signs of possible cancer include:
An unusual lump anywhere on the body
Enlarged lymph nodes, particularly if they’re stuck down to the tissues around them
Changes in skin colour or texture
Enlargement of an organ
Abnormal bleeding
If any of these signs are present, this will not definitively diagnose cancer. You’ll need further testing to determine what’s causing the exam findings.
In addition, cancer doesn’t always cause any apparent physical signs. In fact, in the early stages, it’s common not to show any physical signs of cancer. Even if your physical exam is entirely normal, additional laboratory and/or imaging tests may be needed to check for cancer.
Laboratory Tests
Laboratory tests (commonly known as “lab tests”) may involve checking for certain factors in the blood or faeces, or they may involve taking a small sample of cells from a particular area in order to examine them. Your doctor will determine which of these tests would be recommended in your specific case. If you
Liquid biopsy. A liquid biopsy is a blood test that checks for abnormal fragments of genetic material (DNA or RNA) from cancer cells. The LucenceINSIGHT test checks for DNA from many different types of cancer cells at once, while the GastroClear test checks for RNA from stomach cancer cells.
Complete blood count (CBC). This test measures the levels of various types of cells in the blood. Certain types of cancers, including leukemia and lymphoma, will generally cause an elevated white blood cell count. Cancer that has spread to the bone marrow may lower the counts of all types of blood cells, although this generally doesn’t occur until the cancer has progressed to a later stage.
Prostate specific antigen (PSA) test. This test checks the levels of a protein called PSA in the blood. Various conditions of the prostate, including prostate cancer, may be associated with elevated PSA levels. The Ministry of Health doesn’t recommend this test for all men, because it’s common to have elevated PSA levels even if you don’t have prostate cancer. However, this test may be used in some men, particularly those who are at a higher risk for prostate cancer.
Pap smear/HPV test. This involves gently scraping the surface of the cervix to get a sample of cells, which are then examined under a microscope for signs of cervical cancer. The cells may be tested for certain strains of a common virus known as HPV which can cause cervical cancer.
Fecal immunochemical test. This test checks for signs of blood in a sample of faeces (stool). It can pick up a very tiny amount of blood, which would be too small for you to see. Many conditions can lead to blood in the stool, including colorectal cancer.
For a blood test, you’ll need to go to a medical laboratory after your visit to the doctor, in order to have blood drawn. For a faecal test, you’ll generally be given a card to take home; you will need to swipe a sample of your stool onto the card and then return it as directed. For a Pap smear, your doctor will take a sample of cells from your cervix during your visit.
Imaging Tests or Other Procedures
Imaging tests involve looking at the structure of certain parts of the body. Common imaging tests that may be used to screen for cancer include:
Mammogram. This is an X-ray of the breast tissue, which is used to check for breast cancer.
Chest CT scan. For a CT scan, a machine takes a series of X-rays, which are then put together using computer software to create a detailed image of a part of the body. Chest CT scans can be used to check for lung cancer in people at high risk.
Colonoscopy. This test can be used to screen for colorectal cancer. A colonoscope, which is a long flexible tube with a light and a camera on the end, is inserted through the anus into the rectum and colon. A doctor views the inside of the rectum and colon, looking for abnormal growths. If found, these growths will also be removed during the procedure and then checked in a laboratory to determine whether they are cancerous or precancerous.
Results of the tests
Although the results of your physical examination will be available immediately, it generally takes a few days for you to receive your results from laboratory or imaging tests. When your sample is taken, you should be told how soon you can expect your results, and how you will receive them.
If your results are negative, this is a reassuring result, as it indicates that no evidence of cancer was found. Your doctor will let you know how soon you should repeat the test. Many screening tests are done every one to several years. The time frame depends on the specific test as well as your risk factors for the particular type of cancer that the test is looking for.
If your results are positive, this indicates that you might have cancer. However, in general, additional testing will be necessary in order to arrive at a final diagnosis. It’s definitely possible to get a positive screening test result even though you don’t have cancer – this is known as a false positive. If you get a positive result on a screening test, then your doctor will let you know what additional testing may be needed to determine whether or not you have cancer.
If you would like to take the proactive approach, book a consultation with our specialist doctor to better understand your risks, and discuss which tests are appropriate for you.
You can also add on a fully personalized health and cancer screening during the consultation with your doctor. Our customizable health screening packages allow you to screen for conditions relevant to you, including LucenceINSIGHT, Cancer Marker Test or other tests.