India is a land of contrasts. Over 70% of our people live in villages and a lot of data that we have in health and healthcare are based on community health studies done in rural India. Rapid urbanization and modernization have led to tremendous changes in the disease pattern in our country. Metabolic and life style diseases like diabetes and cancer are on the increase. Unfortunately, we have very little prevalence data from India. Hence we tend to either look at the data from the developed world or choose to derive comfort from the low prevalence data available from community health studies.
Colorectal cancer (CRC) is the third most common cancer in men and second most common cancer in women. It is believed that the prevalence of CRC is low in South Asia. But there are several studies which have reported a high prevalence in developed Asian countries. We have to remember that in most parts of Urban India, particularly in our cities, people have adopted lifestyles similar to those in the developed world. Modernisation is unfortunately equated with westernisation. It is therefore quite possible that the incidence of CRC is on the rise in the ‘developed’ parts of our country.
Colorectal cancer (CRC) is cancer that affects the colon and the rectum. Symptoms of CRC include change in bowel habits - presenting as diarrhoea or constipation, a feeling of incomplete evacuation, bright red blood in stools, tarry black stools, pain and bloating of the abdomen, unexplained weight loss or loss of appetite and generalised tiredness. The feeling of a lump in the abdomen or near the anal region and unexplained pallor tend to be late manifestations of CRC.
Cancer starts when cells in the body divide out of control and form an abnormal growth. Most CRCs start at the inner linings of colon or rectum. These are called polyps. Polyps are of two types – hyperplastic and dysplastic. Hyperplastic polyps are unlikely to transform into cancer. Dysplastic polyps or adenomatous polyps are cancerous. These polyps can develop dysplasia which is a precancerous presentation. If a cancer develops in a polyp, it can grow into the wall of the rectum or colon over a period of time. It can further grow into blood vessels and can travel to nearby lymph nodes or to distant parts of the body.
The treatment of CRC depends on the size, location and spread. Common treatment modalities include surgery to remove the cancer, chemotherapy and radiation therapy. It is of paramount importance to remember that most CRCs are curable if detected early. It is therefore essential to identify ways to detect the cancer at the earliest.
Several medical associations have put up guidelines based on epidemiological studies evaluating the role of lifestyle and dietary factors in the causation of CRC. Dr. Dennis Burkitt in Africa presented the hypothesis that diet plays a vital role in the causation of colonic cancer. High consumption of red meat and processed meat were implicated for several decades.
The incidence rates and absolute burden of CRC in Indians has been slowly rising over the past three decades. The number of cases reported by the Tata Memorial Hospital (TMH), Mumbai, has risen exponentially. Dr. Mohandas of TMH Mumbai, reports that his hospital data shows that some socioeconomically well-to-do Indians like Parsis have a high incidence of CRC. Ali et al stated that the pattern of cancer incidence in British Indians could provide pointers towards primary prevention. Vegetarian diet with high fibre and low meat intake, low calorie diet, reduced alcohol consumption, as well as diet induced variations in intestinal immunity modulated by intestinal bacteria may result in a low incidence of CRC. Several studies have confirmed the potential role of physical activities, consumption of fruit and vegetables and avoiding excess weight gain and tobacco use. Patients who have chronic inflammation of the colon due to diseases like Ulcerative colitis or Crohn’s disease, are more likely to develop CRC.
It has been reported that 75% of all CRCs are preventable. Here are six suggestions that can be a guide to lower your risk of CRC.
- Regular screening: Regular screening tests to look for CRC will be the best way to prevent it. It is advisable to start screening at the age of 50. People with a family history of CRC and those with important risk factors should begin testing earlier and should get tested more often. Faecal occult blood testing or faecal immunochemical testing once a year is recommended. A colonoscopy, which involves a flexible tube with a camera at the end to examine the full length of the inside of the colon, is recommended. If the procedure is done under sedation, it can be painless and fairly easy for you. If polyps or other suspicious growths are found during the examination, they can be removed. Microscopic evaluation of the tissue can identify dysplasia or cancer-like characteristics. In developed societies, Colonoscopy is mandatory for people above 50 years of age.
- Maintain an Ideal Body Weight: Obesity increases the chances of contracting CRC. It is therefore essential to maintain an Ideal Body Weight. An easy reckoner is to check your height in centimetres and deduct 100 from it. That is an approximate estimate of your ideal body weight. (E.g.: If your height is 178cm, your desirable Ideal Body Weight will be 78 kgs).
- Avoid smoking and alcohol: Smoking and alcohol are major causes of at least 14 different cancers including CRC.
- Exercise: I would strongly recommend a 45 to 60 minutes brisk walk daily.
- Avoid red meat and processed meat: Steak and pork increase the risk of CRC. Processed meat like bacon and sausage has also been implicated.
- Supplements: Daily multivitamin, sufficient calcium and vitamin D are known to protect against CRC.