The month of march has been declared colon cancer awareness month, and to coincide with this, web platform ‘Let’s demask cancer’ (only available in Dutch or French) has launched a special website with information, and even a comic book. Main focus of the awareness campaign is to stress the importance of early detection, as well as to highlight therapeutic advances. The motto of the campaign says it all: ‘to know is to act’.
Colorectal cancer often only gets diagnosed at an advanced stage, when the disease presents symptoms. But in 60 to 80% of cases it has taken 5 to 10 years for the cancer to grow from a benign polyp into a malignancy. Early diagnosis is therefore of the utmost importance, especially since 90% of patients who are diagnosed at an early stage can be cured.
Annualy, 3,000 Belgians die because of colorectal cancer. It is the second most prevalent cancer in women (after breast cancer) and the third in men (after prostate and lung cancer). Colorectal cancer can be divided into two types; colon cancer, of the great intestine affects 60% of patients, the other 40% develop cancer in the final part of the intestines, the rectum.
In 60 to 80% of cases colorectal cancer starts out as a benign polyp or adenoma, but undetected and untreated, this can develop into a tumour within 5 to 10 years, which in turn can evolve into an invasive and metastasizing cancer.
Colorectal cancers are caused by many risk factors, but lifestyle is a very important one. Diet (such as the consumption of red meats and cured meats), exercise, tobacco and alcohol intake all play a significant part in reducing –or raising- the risk of colorectal cancer.
In Belgium, there are two strategies to preventing colon cancer. First of all there is a focus on lifestyle, and promoting healthier food, more exercise and less alcohol and tobacco use. Secondly, there is a national cancer screening program, intended to discover and remove precancerous polyps. Since 2009, all men and women between the ages of 50 and 74 are invited to undergo a free screening once every two years. People can send in a small stool sample, which is then checked for the presence of blood. In 97% of all cases, the test result is negative. The 3% that do show blood in their stool sample are called on to undergo a colonoscopy and possible further testing.
Willingness to participate in the free cancer screening program remains low, despite growing numbers. Sciensano estimates that in Flanders the number of screenings has tripled between 2013 and 2018, from 16.2% to 48.1% of all invites. Wallonia shows a much lower participation rate. In 2013 it was 16.4% -same as in Flanders- but in 2018 it had grown to a mere 19.4%.
The campaign from ‘Let’s Demask Cancer’ also urges people to see their G.P. when symptoms occur, even for people under the age of 50. Possible signs of colorectal cancer include:
The pandemic, and the subsequent temporary halt of the cancer screening programs in Belgium, has led to a lower number of people being diagnosed with cancer. The Belgian Cancer Register estimates that the number of new diagnoses has almost been cut in half. Compared to 2019, around 18% fewer men and 22% fewer women were diagnosed with colon cancer.
As in many other types of cancer, personalised targeted therapy has revolutionized the treatment of colorectal cancers. Every patient receives a personalised therapy regime that is tailored to his or her needs. During a Multidisciplinary Oncological Consultation (MOC) the optimal treatment strategy is chosen, based on type and stage of the cancer, its genetic signature, its size, its growth rate, its progression to other organs and the overall health of each patient. Patients are treated with a mix of radiation therapy, surgery, chemotherapy and novel targeted therapies. The treatment still exacts a heavy toll on patients and often brings about adverse events, but progression-free and overall survival of colorectal cancer has been steadily improving.
When a cancer is detected while in an early stage, surgical removal can be an option. Usually in colon cancer, surgery is preceded by radiotherapy, in order to shrink the tumour as much as possible before resection. If the cancer is more advanced or metastasized, another approach is needed, generally consisting of a combination of chemotherapy and targeted therapies during which specially designed molecules, tailored to recognize and attack tumourous cells are administered to the patient.
Targeted therapies slow down tumourous growth and only attack cancer cells in doing so, leaving healthy cells unharmed. Some types of targeted therapy impair blood supply to the cancer cells, others block their ability to multiply and grow. A special type of targeted therapy are monoclonal antibodies, that can enhance the efficacy of chemotherapy and that only affect cancer cells, causing fewer side effects to the patient.