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Text and pic by Fathima Riznaz Hafi
Screening for cancer serves not only to detect cancer but also ‘catch’ it at its pre-cancerous stage, thereby preventing further progression, through intervention.
Though it is encouraged by medical professionals, the general approach is to only undergo screening when symptoms appear. Until such instance they assume to be safe. Contradictory to this lethal assumption, symptoms are not sure indicators of cancer as they may never appear.
“Do not depend on the appearance of symptoms – it is common practice to only seek screening or treatment when symptoms appear; sometimes cancer does not present symptoms and in some cases when it does present those symptoms, the cancer may have already silently advanced to later stages by which time it may be too late for recovery,” says Parkway Cancer Centre Singapore Senior Consultant Medical Oncology Dr. Zee Ying Kiat.
“It is crucial to undergo screening at the ages advised by doctors, and earlier for people with high-risks, because if we wait for symptoms, sometimes it may be too late – sometimes there are no symptoms and the cancer will be spreading without signs – that’s why cancer is called the silent killer,” he cautioned.
Dr. Zee was in Colombo recently to participate in a Lifestyle Health Education Seminar organised by Parkway Hospitals Singapore’s local Patient Assistance Centre. Prior to the seminar, he met up with the media to speak about the importance of screening, frequently stressing the significance of early screening in order to enable subsequent life-saving intervention.
“Screening is a procedure to look for a condition, like cancer, in the absence of any symptoms. A person can be feeling well – entirely asymptomatic but yet may be carrying a cancer. This often represents a cancer at its early stage, such that it does not cause symptoms. Oftentimes if the cancer is carrying symptoms, then it may already be in its more advanced stage. On that basis, if we screen a patient who has no symptoms, then the hope is to pick up the cancer, diagnose it at an early stage, where treatment may be more effective and therefore where the chances of cure may be higher, and save the patient.”
The top three cancers worldwide are lung, colorectal and breast; there are screening processes available for these cancers, which are proven to help save lives. Screening methods vary for different cancers and at the interview Dr. Zee spoke about the screening processes for the most common cancers.
“Screening for colorectal cancer includes the use of a simple test looking for blood hidden in the stool – that’s the ‘faecal occult blood test’; if we find blood in the stool, further tests can be done, particularly a colonoscopy test, where a doctor inserts a lighted instrument with a camera to look at the inside of the colon, whereupon if we identify the cancer, we can take a biopsy sample, to confirm and then the patient undergoes treatment thereafter,” he said.
“Another form of colorectal screening is to go straight to colonoscopy; that is, instead of doing the faecal occult blood test the patient goes directly for screening by telescope test. Some patients have concerns about doing a colonoscopy perhaps because of the preparation needed to clear the bowel movement and also they think it is a potentially invasive test. It is generally a safe and proven test for colon cancer but some patients would choose not to do that.
“Then an alternative screening method is a ‘CT colonography’ which is a CT scan where the images produced can be transformed through software to generate a 3-dimensional picture of the inside of the intestine. It is not invasive but one of its limitations is that if the CT colonography does detect an abnormality, the colonoscopy then still has to be done – because that’s the key test.”
Colorectal cancer screening with colonoscopy is also a form of prevention because a ‘polyp’, which is a pre-cancerous type of condition, if detected at the screening colonoscopy, can be removed and this removal prevents it from turning into cancer in the future. Therefore colonoscopy may serve two purposes – one for screening and one for cancer prevention in patients identified to have polyps.
Colorectal cancer screening usually takes place from the age of 50 and above in patients who have no significant risk factors like a family history or personal history of this cancer.
Breast cancer is the most common cancer affecting women worldwide. A screening process for breast cancer is typically the mammogram, which is an x-ray of the breasts. Mammograms can help to detect cancer earlier, such that treatment can be rendered earlier, with higher chances of survival. Breast cancer related survival is improved with the breast cancer screening mammograms. Screening guidelines recommend that mammograms be performed every year for patients aged 40-50 while for women 50 and above it is every two years.
Most women are afraid to undergo mammograms and pap smears even though they know it is important, because they fear it would be painful and uncomfortable. Dr. Zee advises, “The merits of breast cancer screening are proven and it is more beneficial to undergo that short period of discomfort, such that if a cancer is detected early on, treatment can be rendered sooner, rather than to avoid the discomfort of a mammogram and not detect the cancer early such that the person presents subsequently with an advanced cancer that cannot be cured. It’s really a measure of potential benefits with discomfort linked to a mammogram.”
“For lung cancer, one of the main risk factors is smoking; therefore people who have a history of heavy smoking for a long period of time are advised to undergo annual lung cancer screening – through a CT scan of the chest, as this helps to reduce the chances of succumbing to lung cancer,” he said, adding that a few other factors though less common, can also contribute to lung cancer, for which the same precautions should be taken.
“Cervical cancer is not one of the top cancers worldwide but is a common cancer in women especially in less developed countries. A pap smear is a procedure where the doctor or nurse inserts a spatula to the cervix and takes the sample of the cells from the cervix to then look at under the microscope, with the aim of detecting pre-cancerous as well as cancerous cells.
“Cervical cancer doesn’t just develop overnight; it is a process that occurs over several years – from normal cervix cells to abnormal pre-cancerous cervix cells known as Cervical Intraepithelial Neoplasia (CIN) to cervical cancer cells.So we have this opportunity where when a person who has abnormal pre-cancerous cells goes for screening and thosecells are detected, treatment can be rendered to remove the pre-cancerous abnormality and in doing so, prevent the cervical cancer cells from developing. That is the premise behind the pap smear cervical cancer screening test,” says Dr. Zee.
Pap smears are recommended for women who are sexually active from the age of 25 and above; if the first pap smear is normal then the next one can be done three years later. If an abnormality is found, then the screening is more frequent.
Dr. Zee concluded saying that though there are some cancers for which there are no proven screening tests yet, fortunately the three main cancers – breast, lung and colorectal cancer –have proven screening tests available and he urges that we make use of the tests and undergo screening before symptoms appear, stressing that if we take the necessary precautions by taking tests early we can be saved. He reiterated that the absence of symptoms does not mean we are safe as they may appear late by which time the cancer cells may have progressed too far.
