Can Young People Have Colorectal Cancer?
SINGAPORE - Colorectal cancer is the most common cancer in Singapore, having overtaken lung cancer as the top cancer for men and remaining second for women after breast cancer.
"The life-time incidence of colorectal cancer in Singapore is roughly one in 50 patients," said Dr Wong Soong Kuan, a colorectal surgeon in private practice at Mount Elizabeth Novena.
This means that one in 50 people will have colorectal cancer in their lifetime.
While incidences of the cancer peak at 50 to 70 years of age, it doesn't just strike the old either.
According to gathered by the Singapore Cancer Registry between 2006 and 2010, colorectal cancer cases are on the rise and one out of 10 diagnosed with the cancer of the large intestine was aged below 50.
Such cases of young patients with colorectal cancer usually have a genetic component to it, said Dr Wong.
It can be due to one of four reasons: Familial adenomatous polyposis, cancer family syndrome, a chronic condition called inflammatory bowel disease (IBD) and lastly, sporadic mutation.
Familial adenomatous polyposis is a condition where a child is born with his or her entire colon being carpeted by polyps - an abnormal growth of tissue projecting from a mucous membrane.
Hence, by the age of 18 to 30, they have a higher chance of one of the polyps developing into cancer, Dr Wong explained.
There's another possibility known as cancer family syndrome. Also called lynch syndrome, it is a genetic condition where those affected have an increased risk of developing cancers of the digestive tract.
Such patients have a higher risk of developing colorectal cancer - which often manifests between the ages of 30s and early 40s - and can also develop cancers of the breast, ovaries and uterus.
The third possibility is a chronic condition called inflammatory bowel disease, which is very rare in this part of the world but very common in the Caucasian population, said Dr Wong.
This is when a person's intestine becomes inflamed over many years, increasing the risk of it developing into cancer. Typically if the process has been going on for more than 20 years, there is a condition called dysplasia that can occur and this increases risks of cancer.
The last possibility is sporadic mutation, where a spontaneous mistake in gene duplication predisposes a patient to developing cancer at a young age.
Sporadic mutation is the commonest cause of colorectal cancer in young patients. It is unknown why this is so, although exposure to more carcinogens may be a possibility.
Rare but dangerous
While cases of colorectal cancer in the young are very rare - with the four possibilities combined having less than a 5 per cent chance of occurring in the Singapore population - the problem is that they are often detected late.
Statistically, the chances of surviving for at least five years after treatment stands at 90 per cent for those diagnosed at stage 1 of the disease. However, this number drops drastically to 15 per cent if diagnosed at stage 4.
After the cancer has spread to either the lymph nodes or distant organs, surgical removal alone is not an option and chemotherapy becomes necessary.
"For colorectal cancer, it more or less progresses in a step wise fashion - from the wall, spreading out into the nearer lymph nodes, then the further lymph nodes and finally to the other organs," Dr Wong said.
"Hence, especially so for colorectal cancer, the earlier the stage of the cancer, the better the treatment is going to be.
Signs and symptoms include looser stools, as a result of the intestinal wall becoming partially blocked and the blockage being released intermittently.
It can also be the other way around, where patients complain of stools becoming increasingly difficult to pass as the passage becomes narrower.
Rectal bleeding or unexplained weight loss should definitely be investigated as well.
More uncommon symptoms include pain due to perforation of the intestinal wall, as the tumour gets so large that it breaks through the wall.
Unfortunately, by the time a patient shows any obvious signs or symptoms, the disease has likely progressed to the later stages - where the prognosis is bleaker.
"In fact, more than 50 per cent of patients present themselves in stage 3 or stage 4 of the cancer. That's why I tell my patients that everyone above the age of 50 should go for colonoscopy," Dr Wong said.
Colonoscopy involves a flexible tube with a small camera inserted via the anus to examine the large intestine. If polyps are found, they can be removed at the same time.
"(Colorectal cancer) starts with a pre-cancerous growth called a 'polyp', and the pre-cancerous growth progressively enlarges. Once it reaches a certain size - typically up to 2 to 2.5 centimeters - changes may occur that will cause the polyp to invade and become a full blown cancer," he said.
While the chances of finding a polyp through colonoscopy screening for patients above 50 stands at about 20 per cent, less than 3 per cent of patients test positive for cancer during screening.
The aim of a colonoscopy is to find and remove these pre-cancerous growths before they have a chance to develop into early stage colorectal cancer.
About 1,600 new colorectal cases and 660 deaths are recorded a year in Singapore. Yet according to the Ministry of Health, only one in nine men and one in 13 women aged between 50 and 70 have done a colonoscopy at least once.
And when symptoms do show, young people tend to dismiss them on the mistaken belief that colorectal cancer only affects the old.
Colorectal cancer screening is normally recommended for those above 50, but Dr Wong stressed that if at a person experiences anything out of the ordinary with his or her bowel habits, have rectal bleeding or unexplained weight loss at any age, a doctor should be consulted immediately.
Change in bowel habits includes diarrhoea, severe constipation and change in the calibre or consistency of the stool such as it becoming more mucous or long and pencil-like.
In addition, if you have a family history of cancer, screening should be done five to ten years before the youngest age of a first degree (immediate family) relative diagnosed with cancer.
For example, if you have a first degree relative who was diagnosed with cancer at 40, you should start going for a regular screening once you hit 30.
Because of the difficulty in the symptomatic detection of colorectal cancer in the early stages, the focus is now on identifying individuals more susceptible to the cancer.
"I tell my patients that when you reach 50, it's like a car that goes for a 100,000 kilometer checkup. At 50, everything should get checked up," Dr Wong said.
While the gold standard for colorectal screening is still colonoscopy, a new method called fecal occult blood testing is being advocated by polyclinics.
This is essentially stool testing where patients handle and send samples of their own stool to a laboratory to be tested for hidden blood. However, the test depends on whether the tumour is bleeding and has a 60 to 70 per cent success rate.
Screening involves either an annual faecal occult blood test or 10 yearly colonoscopy beginning at age 50 for average risks individuals.
There is also another test called virtual colonoscopy, where x-rays and computers are used to produce two- and three-dimensional images of the colon.
However, virtual colonoscopy involves some radiation and in cases of poor bowel preparation, stool sometimes can be mistaken for polyps and vice versa - increasing the chances of a higher false positive or negative result.
In addition, a positive result for both stool testing and virtual colonoscopy will still require a colonoscopy to confirm the findings and remove the polyp.
Patients who wish to arrange for a colonoscopy can contact the call centre at Mount Elizabeth Novena for an appointment with a gastro-enterologist or a colorectal surgeon in Singapore. Alternatively, an executive health-screening package is also available.
Colonoscopy is medisave deductable and is recommended for a more precise diagnosis.
Dr Wong Soong Kuan
The Colorectal Clinic Pte Ltd
Mount Elizabeth Novena Hospital