Colon Cancer
The colon comprises different sections, including the ascending colon, transverse colon, descending colon, and sigmoid colon, and any cancerous growths in these areas are considered colon cancer. It should be distinguished from rectal cancer, which occurs in the rectum. Together, they are referred to as Colorectal Cancer.
Like all cancers, they are categorised into stages.
Stage 0
This is the earliest stage of the cancer, also known as carcinoma in situ. The cancer is still confined to the inner layer of the colon or rectum, and has not spread to the nearby lymph nodes or other organs.
Stage 1
The cancer has invaded the next layer of tissue but has not spread to nearby lymph nodes or other organs.
Stage 2
The cancer has penetrated through the wall of the colon or rectum but has not spread to nearby lymph nodes or other organs.
Stage 3
The cancer has spread to nearby lymph nodes but not to the other organs.
Stage 4
This is the most advanced stage of the cancer, and it has spread to other organs or tissues, such as the liver, ovaries or lungs.
Colon cancer is typically diagnosed through a colonoscopy, a procedure used to examine the colon for cancerous growths. Some patients may undergo a colonoscopy due to symptoms suggesting cancer, while others may have a screening colonoscopy without symptoms. During the procedure, biopsies can be taken to confirm the diagnosis of colon cancer. In some cases, colon cancer may be found incidentally during a scan performed for another reason, and a colonoscopy may be recommended to confirm the diagnosis.
Treating colon cancer in Singapore involves two main components: Surgery and Chemotherapy and/or Radiotherapy. If cancer has not spread, surgery is the first-line treatment. This means the cancer is still confined to the colon and the nearby lymph nodes. During surgery, the affected portion of the colon is removed, and the two ends of the colon are joined together (anastomosis). This procedure eliminates cancer while allowing the patient to have regular bowel movements.
Surgery for colon cancer can be performed in two ways: Keyhole (Laparoscopic or Robotic) or open surgery. Both methods involve the same basic steps of removing the tumour and lymph nodes and reconnecting the colon to restore faecal flow.
In Laparoscopic Surgery, specialised instruments with long shafts and grasping jaws, replacing the surgeon’s hands. Energy devices and staplers are also used during the procedure. Keyhole surgery is carried out through three to five small incisions on the abdomen, ranging from 5mm to 15mm. An additional incision of approximately 5cm is needed to remove the cancerous segment of the colon.
Similarly, Robotic Surgery is minimally invasive but an extension of Laparoscopic Surgery. It harnesses advanced high-definition video optics and robotics technology to provide colorectal surgeons with better visualisation and significantly improved precision and accuracy during dissection. The procedure involves freeing the affected segment of the colon from its original position, sealing off the major blood vessel supplying the tumour, and cutting off the segment with a 5cm margin from the tumour. Since it is impossible to separate the tumour from the colon, a portion of the colon must be removed. After removing the affected segment, the two ends of the colon must be rejoined to restore normal faecal flow. This is achieved by either using specialised surgical staplers or stitching the two ends of the colon together by hand.
During hospitalisation, which lasts between 3-10 days, patients resume normal diets gradually over a period of 3-4 days. Patients may have a surgical drain leading out from the abdomen or a nasogastric tube for the first few days to allow drainage of fluids. All patients will have an intravenous cannula for the administration of fluids and medications. After an average hospital stay of 4-5 days, patients will be discharged to recover at home.
It will take around 1-3 months for the patient to recuperate. Patients may experience fluctuating bowel movements before establishing a regular pattern around 6 months after surgery. Surgical wounds typically heal after two weeks, and bathing can resume the day after surgery. Patients may feel weaker after surgery but can expect to return to pre-surgery energy levels within 1-2 months.
Emergency surgery for colon cancer is typically performed in cases of tumour perforation or obstruction. Perforation can occur when the tumour erodes through the colon or causes the colon to tear. Emergency surgery is required in these situations because of the presence of faeces and pus in the abdomen. This surgery is usually open, and there is a high chance that a stoma will need to be created. Obstruction occurs when the tumour’s excessive growth causes a blockage in the colon, preventing the normal flow of faeces. There are two options available for treating obstruction: immediate emergency surgery or non-operative management with decompression tubes. Emergency surgery is typically open and may be required in urgent cases.