Colorectal cancer is very common in Western industrialised countries where it ranks third in terms of incidence and cancer mortality, behind lung and breast cancer. While colon cancer occurs equally in both sexes, that of rectum seems to be more frequent in men with a male-female ratio of about 2:1. Early diagnosis is very important. Five-year survival is 75-90% in the early stages and drops to less than 10% in advanced stages.

Symptoms of colorectal cancer

Symptoms are varied and influenced by several factors such as the site of the tumour, its size and the presence or absence of obstruction or bleeding. They include intestinal irregularities, loss of blood in the faeces, abdominal pain, anaemia, unintentional weight loss and fatigue.

Diagnosis of colorectal cancer

Since the majority of colorectal tumours derive from the malignant transformation of polyps or small benign mucosal expansion due to the proliferation of the cells in the intestinal mucosa, the removal of benign polyps is an effective prevention. Not all polyps are at risk of malignancy. Only adenomatous polyps are really considered precancerous, therefore it is necessary that evaluations of pre-cancerous lesions through endoscopic and histological diagnosis are performed in well-equipped centres and with high volume of cases. 

Modern endoscopic techniques can cure pre-cancerous forms and many types of initial tumour. Surgery has a fundamental role in the ability to heal this cancer when localised. The integration of surgery with chemotherapy, radiotherapy and recently-introduced biological therapies has increasingly enabled curing many patients who would otherwise have had an unfavourable prognosis until a few years ago, including those with advanced disease. 

Diagnosis is initially based on clinical examination, which consists of palpation of the abdomen to look for any masses, and rectal exploration (approximately 70% of cancers of the rectum can be discovered with this operation). The diagnosis is confirmed by performing colonoscopy and biopsy.

Treatment of colorectal cancer

Surgery - integrated with medical care - is the main therapeutic tool in localised forms of the disease, while the type of medical care - integrated with surgery, interventional radiology and radiotherapy - are an important tool in the treatment of advanced forms. Endoscopic therapy, with removal of the polyp in the course of the rectal-colonoscopy, is an effective treatment and replaces surgery in its very initial forms and in the pre-cancerous forms.

It is fundamental that surgery and integrated medical-surgical treatments are performed at centres that can document a high number of patients treated each year, where there is an optimal and constant integration between the different groups of specialists involved in the process of diagnosis and care. All of this expertise has been present at IEO since its foundation. The Ministry of Health data (AGENAS 2013) rank IEO among the top national centres and at the top in Lombardy for the number of patients annually treated for colorectal cancer, with a high proportion of surgeries performed with minimally-invasive laparoscopic or robotic techniques.

Causes of bowel cancer

There are many causes that contribute to this disease, only a few of them are known and have appropriate procedures in place for prevention.

• Genetic factors. Colorectal cancer risk can be inherited. This happens if there have been repeated cases of this tumour in the family of origin (especially if the affected subjects were under the age of 50) or if hereditary diseases predisposed to this tumour have occurred (of note the hereditary adenomatous polyposis and hereditary colorectal carcinomatosis on a non-polyposis basis, also called HNPCC or Lynch syndrome). It is estimated that the risk increases 2-4 times in first-degree relatives with cancer or polyps of the large bowel. Total colonoscopy as a screening test is recommended in patients with a documented genetic risk. At IEO, genetics and cancer prevention programmes are active for the diagnosis of these conditions and the prevention of many hereditary cancers.
• Nutritional factors and lifestyles. Many studies show that a diet high in calories, proteins and animal fats and low in fibre is associated with an increase in intestinal tumours. Conversely, diets high in fibre (characterised by a high consumption of fruit and vegetables) appear to have a protective role. The adoption of the so-called Mediterranean diet – with its high content of vitamins, fibre and antioxidants - is a tool for prevention, as well as weight monitoring and moderate physical and sporting activity (it only takes 20 minutes a day of walking briskly to significantly reduce the risk). Also abstention from smoking and avoiding alcohol abuse have a favourable impact.
• Non-hereditary factors. Chronic inflammatory bowel diseases (including ulcerative colitis and Crohn's disease), a past medical history of colon polyps or a history of colorectal cancer are important. Not to be forgotten is age; incidence is 10 times higher among people aged between 60 and 64 compared to those who are 40-44.

Occult blood in the stool is the most widely used screening tool; evaluation of this condition is performed annually from the age of 50. Thanks to the good specificity and sensitivity of the new generation immunoassays, the test can detect tumours before they become symptomatic. In case of a positive faecal test, colonoscopy should be performed. Colonoscopy is indicated as the first test for early diagnosis in subjects with documented risk factors (family history, previous polyps or bowel cancer, idiopathic colitis).

Nutritional prevention for bowel cancer

Based on careful evaluation of the results of scientific research, it has been possible to identify specific risk factors and protective nutritional factors for specific types of cancer. Experts have classified the results into four levels: "convincing evidence", "probable evidence", "limited evidence" and one last level that includes effects for which evidence of association with the cancer is “highly unlikely". The following probable and convincing evidence forms the basis for the recommendations:

According to the Worldwide Fund for Research on Cancer, convincing nutritional risk factors for increasing the risk of colon cancer are:

• red meat (convincing evidence)
• processed and preserved meat (convincing evidence)
• alcoholic beverages (convincing evidence for men)
• alcoholic beverages (probable evidence for women)
• overweight and obesity (convincing evidence)
• abdominal fat (convincing evidence)

The protective factors that have shown convincing evidence in lowering the risk for this disease are regular physical activity and the consumption of foods rich in fibre such as whole grains, legumes, vegetables and fruits. The consumption of garlic and milk has shown probable evidence for the prevention of this type of cancer.

Surgery is the treatment of choice for this cancer, being indicated in all the localised forms of the disease. In the majority of patients, surgery relies on extensive use of minimally-invasive techniques (laparoscopy and robotics) with an appreciable advantage in postoperative recovery times. The numbers of interventions performed put the IEO General Surgery Unit at the forefront in the national rankings. In particular, interventions for the treatment of rectal cancer through robotic techniques have exceeded 300, which represents one of the largest caseloads for a single centre in the world.

The surgery of rectal cancer has become more and more conservative over time. Integration with advanced chemo-radiotherapy methods in the preoperative period and the adoption of innovative surgical techniques allows us to minimise the number of interventions with demolition of the anal sphincter (which would lead ultimately to the opening of a stoma), now limited only to cases of direct tumour infiltration of the anal sphincter.

In some cases, chemotherapy and/or radiotherapy for preventing recurrence in patients at risk are associated with surgery (adjuvant therapies) or they are an alternative to surgery in preventing the development of cancer cells that may have already spread around the tumour or to other parts of the body through the blood and lymphatic circulation.

Surgery of metastases (liver, lung, ovary) associated with the use of other local therapies (thermal ablation, radiotherapy) offers a valuable tool in the treatment of advanced disease, contributing to increased chances of cure and prolonging survival.

Trials in progress at IEO are aimed at:

• identifying earlier and more reliable endoscopic diagnostic tools (such as Confocal Laser Endomicroscopy)
• defining the criteria for the objective assessment of the quality of the endoscopic examination
• establishing the benefits of minimally-invasive robotic surgery in rectal cancer
• studying the prognostic factors in radically operated colon cancer
• finding new biomarkers
• defining the lymphatic basin of colon cancers
• clarifying the role of Diffusion MRI in the surgical treatment of rectal cancer undergoing robotic surgery
• investigating the prognostic role of circulating tumour cells and circulating DNA in peripheral venous blood of patients with rectal cancer.

An important part of studies and research is dedicated to prevention based on the study of the genetic risk. In addition, major effort is aimed at clarifying the role of adjuvant and palliative chemotherapy and radiotherapy in cases where they are indicated, through specific dedicated studies, reported in the "Research" section.