Is colon cancer preventable?

Colorectal cancer is the third most common cancer in the world and its prevalence is increasing rapidly in certain regions. Middle East Health speaks to Professor Heinz-Josef Lenz, an eminent cancer research specialist based at the University of Southern California Keck School of Medicine, about the disease, its epidemiology, and options for prevention and treatment.

Middle East Health: What exactly is colorectal cancer? Are there known causes of its development? Can it be inherited? What is the risk of it spreading in the body?

Professor Heinz-Josef Lenz: Colon cancer is one of the most common cancers in the world and one of fasted growing cancers in Asia. Most colon cancers develop from a polyp which is a benign growth of the inner lining of the gut. The most interesting fact of the development of colon cancer is that we can very effectively prevent it since it is present in precancerous form, which we can, in most cases, easily spot as a polyp. Most of the colon cancer develops within 5-10 years, giving us a unique opportunity to prevent this cancer with colonoscopies which can identify the polyp and then it can be easily removed. Since colon cancer usually develops in patients older than 50 years we recommend a baseline colonoscopy at 50 years and then every 5-10 years depending on the findings.

We also know very well the risk factors for colon cancer. The main factors are red meat, alcohol, obesity and many other lifestyle factors. It is also very important to recognize the symptoms of colon cancer. If the cancer is in the left side of the colon the symptoms are usually easy to recognize and include constipation and diarrhoea, blood in the stool, pain with bowel movements and others. However, if the cancer grows on the right side, the symptoms are less characteristic and can be like abdominal discomfort and are often mistreated as stomach upset. Any on-going abdominal discomfort should be evaluated and a colonoscopy considered.

In addition to the lifestyle factors leading to colon cancer, there is also a familial form called Lynch Syndrome. If there is any family history of colon cancer and possible ovarian endometrium or gastric cancer, the person should to be evaluated for a possible genetic predisposition. Patients with a genetic predisposition develop colon cancer much earlier (under age of 50) and often on the right side without developing polyps. These patients need to be seen by a genetic counsellor and undergo specific surveillance. We know from studies, if we identify this genetic predis-position, we can successfully prevent any patient in this family dying from colon cancer while undergoing surveillance.

MEH: What is the epidemiology of colorectal cancer – in the World, the US, Europe, Asia and the Middle East (for comparison)?

HJL: The highest incidence of colon cancer is in the Western world, South America, and now also in Asia following the spread of Western diet in the world. In the US, the incidence has been decreasing mainly due to more screening with colonoscopies. Asia now has a higher incidence than the US – Japan has double the incidence of the US – because of the change of lifestyle, increasing consumption of a Western diet and less exercise, increasing obesity and more alcohol.

MEH: Is there a gender bias? If so, why?

HJL: Yes there is a link to gender. We know that premenopausal women have significant decrease in the risk of colon cancer. We also know that women who take hormonal replacement have lower risk of colon cancer. This might be only effective on the right side of the colon. However, postmenopausal women have the same risk or maybe higher risk than men. We know that oestrogen plays a role in the right-sided colon cancer and the premenopausal level of oestrogen can prevent the development of disease.

MEH: What are the mortality figures for colorectal cancer? How does it rank (for mortality) compared to other diseases?

Overall, colon cancer is the third most common disease and one of the most lethal (2nd) depending what statistics you look at. It is a major health problem around the world.

MEH: What do you recommend doctors tell their patients with regards prevention?

My recommendation is to avoid red meat, decrease alcohol consumption, have regular exercise and eat the Mediterranean diet. Get colonoscopy at 50 and if there is any family history of the disease you may need to check for the disease earlier. If there are any on-going symptoms in the abdomen, make sure that a colonoscopy is considered. Colon cancer can be easily prevented with regular exercise 20 minutes twice a week, which reduces the risk of colon cancer by 50%.

MEH: Once diagnosed – how do you classify the different stages of progression / advancement of the cancer?

Depending on the stage of the colon cancer, we do surgery, chemotherapy and radiation. For colon cancer located in the rectum, we usually – depending on the tumour size – give chemo and radiation prior to the surgery. For most colon cancers we perform surgery, but this depends on the tumour growth in the bowel wall and if the cancer travelled to the lymph nodes or spread to other organs. We stage the cancer as I, 2, 3 or 4. Stage I and II disease usually don’t require any further therapy and over 80-90% are cured.

Oncology Conference in Abu Dhabi in November last year). Can you tell us about these options?

The introduction of the novel drug regorafenib is important because it gives the oncologist a new tool in their fight against colon cancer. It is a ‘smart drug’ targeting a very important genetic alteration in colon cancer enabling the disease to grow and metastasize. This oral medication has shown that it prolongs life in patients who have exhausted the standard therapies. This drug has a very unique mechanism of action which explains its efficacy in patients with colon cancer. It is also easy to give and well tolerated.

MEH: Is colorectal cancer curable?

Colon cancer is a unique disease. Even when the disease has metastasized to the liver, we still have a chance for cure. This is completely different to other cancers, such as lung or breast cancer. It has to do with the special metastatic pattern of the disease and the ability to remove successful liver metastases, since liver is the only organ which can rejuvenate. With increasing efficacy of our therapies we will cure more and more patients. The challenge in the future will be using molecular testing to identify patients who benefit the most from our therapies and the increased understanding of the molecular make up of colon cancer will not only help to select patients, but identify new treatment options. We are in the middle of a molecular revolution and I have no doubt that we will find better therapies using our increasing knowledge of the molecular pathways in this disease.

MEH: Do you have any specific recommendations for doctors and / or health authorities in the Middle East?

I have always been impressed by the knowledge and training of oncologists in the Middle East. I have no doubt that the new treatments and the new molecular testing will be quickly integrated in the treatment of patients with colon cancer in the Middle East. We can only understand this disease with global collaborations. We unfortunately know very little about colon cancer in the Middle East since aetiology and different ethnic backgrounds may play a role in the development, progression and outcome of patients with colon cancer. It would be incredibly exciting to better understand the genetic background and molecular make up of colon cancer in this region. OncLive - Colorectal cancer

 Date of upload: 17th Jan 2014


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