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Colon cancer is the most common tumour among the general population. In Spain, 26,000 new cases are diagnosed annually, and it is the second leading cause of death after lung cancer. The incidence of the tumour increases from the age of 50 until it reaches its peak in the 80s.
The most prominent risk factors are a diet rich in unsaturated fats and red meat. A sedentary lifestyle, alcohol and smoking are also associated with an increased incidence of colon cancer.
These factors are, however, modifiable. As such, a diet rich in fibre, fruits, vegetables and fish is recommended.
Approximately 95% of colon tumours are sporadic (i.e. without a familial or hereditary component), and only 5% have a genetic component, usually associated with familial adenomatous polyposis and Lynch syndrome.
However, 15% of sporadic cases have genomic alterations similar to hereditary cancer, such as microsatellite instability or MLH1 mutations.
Sporadic cancers present with a BRAF gene mutation, so it is important to determine this to differentiate between the two types.
26,000 new cases are diagnosed in Spain every year
It is the second leading cause of death after lung cancer
The incidence of the tumour increases from the age of 50 onwards
In most cases, there is a disturbance in the normal stool rhythm with alternating constipation and diarrhoea, and occasionally there is blood or mucus with the stool.
In the early stages of the disease, clinical manifestations are often subtle. In most cases, there is a disturbance in the normal stool rhythm with alternating constipation and diarrhoea, and occasionally there is blood or mucus with the stool.
In right-sided colon tumours, occult bleeding with faeces is more frequent, resulting in microcytic anaemia, asthenia and weight loss.
In left-sided colon tumours, the symptoms tend to be related to intestinal obstruction and constipation, and the presence of abdominal masses is less common.
In more advanced cases, it can present as intense abdominal pain secondary to perforation of the affected intestinal tract, and in other situations, it can also fistulise other nearby organs (bladder, vagina, urethra, etc.).
As colon cancer is highly prevalent and its prognosis is associated with early detection, it is included in population screening programmes by means of a faecal occult blood test and, if positive, a complete colonoscopy.
These controls should be offered from the age of 50 years onward and, if there is a history of first-degree or adenomatous polyposis, starting from the age of 40 years.
As colon cancer is highly prevalent and its prognosis is associated with early detection, it is included in population screening programmes by means of a faecal occult blood test and, if positive, a complete colonoscopy. These controls should be offered from the age of 50 years onward and, if there is a history of first-degree or adenomatous polyposis, starting from the age of 40 years.
The definitive clinical and histological diagnosis of a colon tumour is obtained by performing a complete colonoscopy (or coloscopy), which has an accuracy rate of close to 95%.
After a histological diagnosis of colon neoplasia, a thoraco-abdominopelvic tomography (CT) scan is required to determine whether or not there are distant metastatic lesions, neighbouring organs that are affected, or signs of peritoneal carcinomatosis.
Magnetic resonance imaging (MRI) of the liver is necessary in cases where the nature of the liver’s lesions is unclear.
PET/CT does not appear to add further information in the routine evaluation of colon cancer, but it may be useful in cases of suspected metastatic disease for further treatment planning.
The diagnosis is completed with a tumour marker study (CEA and CA 19-9 tests).
To determine the exact extent of the disease, it is classified according to the TNM (Tumour, Node, Metastases) system of the Union for International Cancer Control (UICC).
Treatment will depend on the stage of the disease and the clinical situation of the patient. In all cases, the treatment decision must be agreed by consensus in the Multidisciplinary Digestive Tumour Committee.
After the definitive histological study, the Digestive Tumour Committee again decides whether or not the patient will require complementary chemotherapy treatment. The poor prognostic factors that set the conditions for this decision are: T4 tumours, perforated tumours, metastatic involvement, metastatic lymph nodes or less than 12 analysed, elevated preoperative CEA, and lymphovascular involvement.
Approximately 20-25% of patients have metastases at the time of diagnosis (synchronous metastases) and many others will have metastases at follow-up (metachronous metastases). Hepatic surgery on liver metastases, thoracic surgery on lung metastases, and hyperthermic peritoneal oncological surgery on peritoneal metastases, together with chemotherapy, can achieve, in very specific cases, survival rates of 40-45% at 5 years.
In colon cancer, surgical treatment is the mainstay in most cases. Its aim is to remove the affected intestinal tract and its lymphatic drainage territory, with ample safe surgical margins. If any adjacent organ or structure is affected, an en bloc resection must be performed.
The most commonly used approach is currently minimally invasive—either laparoscopic or robotic—but still respecting the same precepts of oncological surgery as described above.
The surgical technique will vary depending on the location of the primary right-sided colon tumour (right hemicolectomy or extended right hemicolectomy) or of the left-sided colon tumour (left hemicolectomy, sigmoidectomy). In most cases, a primary anastomosis is performed to reconstruct intestinal continuity. In some cases, such as emergency surgery or in patients with associated risk factors, a temporary or permanent stoma may be created.
Approximately 20-25% of patients have metastases at the time of diagnosis (synchronous metastases) and many others will have metastases at follow-up (metachronous metastases). Hepatic surgery on liver metastases, thoracic surgery on lung metastases, and hyperthermic peritoneal oncological surgery on peritoneal metastases, together with chemotherapy, can achieve, in very specific cases, survival rates of 40-45% at 5 years.
After the definitive histological study, the Digestive Tumour Committee again decides whether or not the patient will require complementary chemotherapy treatment. The poor prognostic factors that set the conditions for this decision are: T4 tumours, perforated tumours, metastatic involvement, metastatic lymph nodes or less than 12 analysed, elevated preoperative CEA, and lymphovascular involvement.
Approximately 20-25% of patients have metastases at the time of diagnosis (synchronous metastases) and many others will have metastases at follow-up (metachronous metastases).
The Digestive Tumours Committee is made up of a multidisciplinary team of expert professionals.
The General and Digestive Surgery Service deals with the prevention, diagnosis and treatment of colon cancer.
The Service's team of professionals accompanies cancer patients throughout the whole disease process.
A clinical trial is a research study carried out on people with the aim of learning more about how the body reacts to certain treatments. These trials generally seek to find drugs that are more effective than the current best therapeutic option for patients, or that have similar efficacy but a better toxicity profile.
Bearing in mind that almost all currently available treatments are the result of clinical research, the importance of clinical trials is obvious.
The IVO has a clinical trials unit for all types of tumours and participates in phase 1-3 studies as well as other types of studies.
Whether you receive the news of an initial diagnosis of cancer or a relapse, coping with cancer can be emotionally overwhelming. Each person has their own way of coping with a colon cancer diagnosis, but there are some recommendations that can help you through this process:
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