Treatment for colorectal cancer depends on the location, size, stage and grade of the cancer.
An individual with colorectal cancer should be assessed by a multi-disciplinary team of specialists to determine which modality of treatment is best suited for them. Colorectal cancer treatment requires the involvement of different specialists – surgeons, interventional radiologists, nuclear medicine physicians, medical oncologists, radiation oncologists and palliative medicine specialists. Such multi-disciplinary care is available at SingHealth healthcare institutions.
Depending on the stage of cancer, there are different approaches that the surgeon may use during surgery.
In very early stages colorectal cancer, the surgeon may only remove the cancerous growth or a part of the inner lining of the colon. In more advanced stages, the surgeon may remove the section of the colon or rectum that is diseased. Nearby lymph glands will also be removed to ensure adequate removal of all cancer cells. Minimally invasive surgery or laparoscopic surgery may be performed, where the surgeon performs the operation through several small incisions in the abdominal wall This method has been shown to minimise pain after surgery and accelerate recovery, but is not suitable for all cases of colorectal cancer.
During colorectal cancer surgery, an artificial opening for the colon called a stoma may be required. This opening allows waste to be removed from the body when the normal opening cannot be used or has to be removed. A stoma may be temporary or permanent. Specialist nurses are available to help patients or their caregivers with stoma maintenance and care.
Sometimes, chemotherapy or radiotherapy may be used before or after surgery.
Increasingly, some patients with stage 4 cancer with limited spread to the liver, lung and/or the peritoneum may be suitable for surgical treatments that can provide long term disease control or even cure. Our colorectal surgeons and oncologists work closely with the liver, lung and peritoneal surgeons to coordinate surgical treatments in patients with limited spread to the other organs for which curative intent surgery may still be possible.
Chemotherapy and/or targeted therapy
Chemotherapy is the use of anti-cancer drugs to destroy cancer cells. The type of chemotherapy, how it is administered and the number of courses required, depends on the type of cancer and how well the patient is responding to the drugs. Molecular profiling of the tumour is often performed to characterise each patient’s cancer and assist in selecting the medications that a patient is more likely to respond to. We now have more systemic treatment options including targeted therapy and immunotherapy, which will be explained in more details below.
In patients with stage 2 and stage 3 cancer, chemotherapy (oxaliplatin, fluoropyrimidines) may be administered after surgery for up to 3 - 6 months, to reduce the risk of recurrence and therefore increase chances of long term survival. Patients will be followed up for 5 years with regular physical examination, blood tests and interval radiological imaging, plus colonoscopy as indicated.
In stage 4 disease where the cancer has spread to other organs, chemotherapy and/or targeted therapy is given to control the cancer in order to shrink the tumour, and to control the spread of cancer cells. Some treatments include chemotherapy (oxaliplatin, irinotecan and fluoropyrimidines), anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (panitumumab, cetuximab), anti-vascular endothelial growth factor (VEGF) monoclonal antibodies (bevacizumab, ramucirumab) and oral therapies such as encorafenib, regorafenib and TAS-102. On top of systemic therapy, some patients with oligometastatic disease (stage IV cancer with limited sites of spread) may also be amenable to further surgical resections and/or locoregional therapies. Newer treatments and clinical trials may be available for some patients and these can be discussed with your medical oncologists.
Some side effects may be experienced with chemotherapy (mouth sores, rashes, numbness, loss of appetite, nausea/vomiting, diarrhoea, low blood counts, infections, allergic responses and rarely organ dysfunction) but your condition will be monitored closely by your oncologists and usually the treatments are fairly well tolerated. We also have a strong support from palliative care services, medical social services and oncology specialist nurses/pharmacists.
Radiation or radiotherapy uses high-energy X-rays to kill cancer cells. The aim of radiotherapy is to destroy more cancer cells and spare as many normal cells as possible. Radiation therapy is sometimes used after surgery for colorectal cancer to destroy any remaining cancer cells and prevent the cancer from recurring. It may also be used to reduce the size of the rectal cancer before surgery.
In some cases, when surgery is not an option, radiation therapy is used to control the growth of tumours which are causing pain or bleeding.
Immunotherapy is a treatment that uses the patient’s own immune system (white blood cells) to fight cancer. It is given intravenously and usually used in selected cases of patients with microsatellite instability high (MSI-H) colorectal cancer, which is usually linked to a hereditary type of colorectal cancer syndrome called Lynch Syndrome. MSI-H colorectal cancers can also occur in patients without family history.
Supportive (palliative) care
Palliative care is specialised medical care that provides relief from pain and symptoms of serious illness so that a person with cancer feels better and has a better quality of life. The palliative care team of doctors, nurses and other healthcare professionals provide an additional layer of support that complements ongoing care.
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