Colorectal cancer (CRC) is the most common cancer in Singapore. Although it is also one of the more preventable and treatable cancers, many people are not taking the pro-active steps of performing cancer screening. As such, the majority of CRC are still diagnosed in the advanced stages.
What is Colorectal Cancer?
Colorectal cancer refers to a malignant (vs benign) growth of the colon and/or rectum, ie. the final part of our digestive tract before the anus. Colorectal cancer starts as a polyp, or small growth, along the inner wall of the colon and rectum. Not all polyps become cancer and since they usually take years to become cancerous, if at all, there is a potential ‘lead time’ to stop the process and prevent cancer by removing the polyp during a colonoscopy.
Prevalence of Colorectal Cancer
Worldwide, there were 1.8 million new cases diagnosed in 2018.
Colorectal cancer is the most common cancer in Singapore, first among men and second among women (a breast cancer). It was also the 2nd and 3rd most common cause of cancer deaths in Singaporean men and women, respectively.
Based on recent figures from the National Registry of Diseases Office (NRDO) of Singapore, the incidence of colorectal cancer in Singapore rises sharply after 50 years of age, with 5103 men and 4221 women diagnosed with colorectal cancer between the period of 2010 and 2014. In the same report, it was also found that more than 3 in 4 colorectal cancer patients diagnosed, regardless of gender, were above the age of 55.
Numerous risk factors are involved in developing colorectal cancer, including modifiable and non-modifiable factors.
Modifiable factors include lifestyle and behavioural factors such as obesity, physical inactivity and smoking, all of which can potentially increase an individual’s risk of developing cancer if not controlled.
Other factors that cannot be modified include genetic or hereditary factors, such as having family members with colorectal polyps and colorectal cancer. As such, one may never be entirely free of risk.
Thus screening should still be performed to be absolutely sure that one does not have polyps or cancer, and should preferably be done when the patient is well and not displaying any symptoms.
Symptoms and signs
In the early stages when the cancer is small, there are often no symptoms.
Sometimes, patients may present with signs such as per rectal bleeding, which could mimic more common benign conditions like haemorrhoids. However, by the time symptoms arise, the cancer is often larger and possibly of an advanced stage, ie. having already spread to other organs. Symptoms may include signs of ongoing blood loss such as being pale, lethargic, or feeling breathless with minimal exertion (eg. even walking on flat ground). Other sinister symptoms include significant loss of weight or appetite, abdominal pain, feeling a lump, or bloating. Patients may also experience a change in bowel habit, such as having alternating diarrhoea and constipation or stools with decreased calibre (narrow or pencil-thin).
As symptoms often present only later or mimic more common benign conditions like piles, the majority of colorectal cancers are still only diagnosed in their advanced stages, having already spread beyond the colon or rectum. But this can be easily avoided if people go for screening, ie. when they feel well.
The most common and effective treatment for colorectal cancer is surgery, which removes the affected portion of the colon with the cancerous growth. If cancer is discovered in the early stages, this can produce an excellent outcome. Other treatments include chemotherapy and radiotherapy, but this is usually reserved for more advanced cancers which have spread beyond the colon and rectum.
At Mark Wong Surgery, laparoscopic surgery is the preferred method of surgery and is also recognised as the standard for colorectal cancer surgery in developed countries such as Singapore. Also known as ‘keyhole’ surgery, this technique uses advanced technology (including 3D and high-definition optics) to perform surgery through small cuts on the belly.
Compared with conventional ‘open’ surgery that utilizes bigger cuts, the smaller cuts in laparoscopic surgery mean the wounds are smaller and patients experience less pain. The internal organs are also less exposed to the cold operating room environment, reducing the chance of infection, and allowing patients to resume eating faster after surgery. Put together, all these translate to a shorter hospital stay and faster return to normal activities.
At Mark Wong Surgery, our specialist is also trained in Robotic colorectal surgery, one of the latest advancements in laparoscopic surgery. It makes use of a robotic console from which the surgeon controls a robotic machine that performs the surgery through small cuts in the belly.
Robotic surgery is an even more precise method of keyhole surgery than laparoscopic surgery, as the robot has more degrees of movement in wielding the instruments, similar to that of the human wrist. It is also more stable, providing stereoscopic 3D vision and better magnification, enable more precise surgery and stitching.
Such features make it very useful when operating in narrow confined areas like the pelvis, where organs like the rectum are situated. Studies have shown better results in terms of sexual function and continence after robotic surgery compared to laparoscopic surgery. Robotic surgery is often recommended for cancers involving the lower end of the colon, rectum and anus. It has been shown to be as safe as conventional laparoscopic surgery with the above-added benefits.
Prevention & Screening
Colorectal cancer is preventable; since it starts as polyps and takes years to become cancerous, if at all, we can remove polyps to stop them from becoming cancerous. In its early stages, it is even potentially curable. Unfortunately, we are still diagnosing colorectal cancer at advanced stages due to public ignorance and fear of screening.
Based on the NRDO data mentioned earlier with the incidence of colorectal cancer rises sharply after 50 years of age, and it is recommended that adults should screen for colorectal cancer once they reach 50 years of age. In fact, with more patients diagnosed below the age of 50 years, the USA has recommended that the age of screening be lowered to 45 years old. In general, one should go for screening starting 10 years before the youngest case of colorectal cancer (CRC) in the family or at 50 years old, whichever is earlier. For example, if you have a family member with CRC at age 50 years, you should start screening at 40 years old. This is because all CRC arises from polyps which can take several years to become cancer. As such, screening and detecting polyps which can be removed can potentially prevent one from developing colorectal cancer.
Screening for colorectal cancer can begin with a simple FIT (Faecal immunohistochemistry test) kit that detects occult (or invisible) blood in the stool that cannot be seen with the naked eye. FIT kits are free for all Singaporeans and PRs above the age of 50 years. They can be obtained from polyclinics and pharmacies, and are administered at home. If the results are positive for blood, patients should go for a colonoscopy. However, in the presence of overt or frank visible bleeding above the age of 50 years with no recent colonoscopy done, a FIT is not necessary and colonoscopy should be done instead.
Colonoscopy is regarded as the ‘Gold Standard’ for detecting colorectal cancer. At Mark Wong Surgery, our specialist is trained in this procedure which represents a safe and accurate method for detecting colorectal polyps or cancer. A bowel preparation is taken to cleanse the colon of stools before the procedure. The scope is then performed as a day-case procedure under sedation with minimal discomfort. Furthermore, it allows the doctor to perform a biopsy to remove and/or confirm the nature of the lesion seen during the scope. Using high-definition, fibre-optic technology, a flexible tube inserted into the anus allows the doctor performing the procedure to view the inner wall of the colon and rectum in detail, so that any polyps or cancers can be identified, biopsied or removed.
Another alternative is a CT scan for the colon and rectum (CT colonography), but it does not allow for removal or biopsy of suspicious findings, something that will still require a colonoscopy.