What is Colorectal Cancer (CRC)?
Colorectal Cancer is a cancer that occurs in the colon (large intestine) and the rectum. Within Colorectal cancer, about 70% of malignancies occur in the colon, and 30% appear in the rectum. Most colorectal cancer develops gradually over a number of years. Usually tumour growth begins as a non-cancerous polyp on the inner lining of the colon or rectum.
Two kinds of polyps exist:
- Adenomatous polyps (adenomas) – can change into cancer.
- Hyperplastic polyps and inflammatory polyps – not pre-cancerous.
What are the key statistics for the incidence of CRC?
In 2014, almost 153,000 people died from colorectal cancer in the EU-28, equivalent to 11.3 % of all deaths from cancer and 3.1 % of the total number of deaths from any cause. The share of deaths attributed to colorectal cancer was 3.4 % for men and 2.8 % for women. Among the EU Member States, the share of the total number of deaths that were attributed to colorectal cancer peaked at 4.1 % in Croatia, falling to around half this share in Cyprus (2.0 %) with shares below 2.5 % also recorded in Lithuania, Romania, Finland, Bulgaria, Greece and Latvia (source).
According to the World Cancer Research Fund International colorectal cancer was the third most common cancer worldwide in 2012 with nearly 1.4 million new cases diagnosed (source).
What are the causes?
Family History of the disease may be relevant. CRC usually occurs in those over 50. Women are at slightly higher risk than men. Diet may also be a contributing factor – high-meat, high-fat, low-fibre diet may encourage the production of carcinogens.
What are the symptoms?
Abdominal pain, blood in the stool, and rectal bleeding are common symptoms. However, there may be no symptoms or minimal symptoms. Experience of the disease can vary widely depending on the location of the cancer within the large intestine.
How can colorectal cancer be detected?
Early detection is key to help controlling cancer. Often colorectal cancer starts with polyps, which are small, non-cancerous growths that form on the inner lining of the colon. There are many tests which can help identify colorectal cancer:
- Flexible Sigmoidoscopy
- CT Colonography
- Faecal Occult Blood Test
- Faecal Immunochemical Test
Is lifestyle important?
Lifestyle can have an impact on colon health. A healthy diet that is low in fat, and high in fruits, vegetables, and fibre has been linked with decreased risk of colorectal cancer. Other factors that can increase the risk of colorectal cancer include obesity, physical inactivity, smoking, and heavy alcohol use.
Summary of Treatment Options
Treatment of Colorectal cancer can include surgery, radiation therapy, chemotherapy, and other targeted therapies, or a combination of these. Doctors who treat cancer choose treatments based on the state of the disease, and the particular condition of the individual.
Surgery means the removal of the tumour and surrounding tissue during an operation.
This involves the use of high-energy X-rays to kill cancer cells, commonly used for treating rectal cancer.
In chemotherapy drugs are used to kill cancer cells, usually by stopping the cancer cell’s ability to grow and divide.
For many years, 5-flourouracil (5FU) plus leucovorin [IFL] was the only effective treatment regime, though overall survival times associated with the treatment were limited. Recent advances to the treatment (now known as FOLFOX (5-FU with leucovorin and oxaliplatin)), have helped increase average overall survival, and there are now a variety of different chemotherapy options on offer.
Targeted therapy is an approach that targets the cancer’s specific proteins, genes, or the tissue environment that enable the cancer to survive. Examples include:
- Epidermal Growth Factor Receptor Inhibitors: This treatment can help to shrink and stabilize the growth of colorectal cancer by disturbing the process by which tumours develop. The two drugs available for this treatment – Cetuximab and Panitumumab – do not work as well for tumours that have specific gene mutation (changes) within a gene called KRAS. Therefore, for many people, this treatment is not a suitable option.
- Anti-angiogenesis therapy: This treatment focuses on stopping angiogenesis, which is the process of making new blood vessels. Because a tumour needs the nutrients delivered from blood vessels to grow, the goal is to effectively starve the tumour. Bevacizumab (Avastin) – an antibody therapy – was introduced in 2004, and, when combined with chemotherapy, has led to an increased overall survival for patients with metastatic (advanced) Colorectal Cancer. It has become a standard first-line treatment option. However, the response to this treatment is heterogeneous, meaning that not everyone benefits. It can also have negative side effects.
How will COLOSSUS Help?
COLOSSUS aims to identify new ways to classify patients with a specific type of colorectal cancer (MSS RAS mt mCRC) based on disease mechanisms and to help address the need for more targeted and personalised treatment options.