Colorectal Cancer can be tackled with timely screening and treatment. Here's everything you want to know about it

Here are factors which might be responsible for Colon Cancer.

The month of March is dedicated to generating awareness around colorectal cancer so that timely screening and treatment can be ensured.Colon cancer is one of the most common cancers across world and responsible for a large number of deaths. According to WHO, 774000 deaths occurred across the world in 2015 due to colon cancer. Globally, colon cancer is the 4^th most common cancer among women and the 3^rd most common cancer among men. According to the American Cancer Society, an estimated 50,630 deaths will occur due to colorectal cancer in 2018. Colon cancer incidence is also increasing in Asia and has already become one of the leading causes of death.In India, though the incidence is rising, the number of cases is far less than the west. It is the fifth leadingcause of cancer related deathsin India.

Colorectalcancers begin as small clumps of cells called 'Adenomatous Polyps' (Non-cancerous growth in the colon/rectum), which can be found lining the gastro intestinal tract. 96% of all colon cancers are Adenocarcinomas(a malignant tumour formed from glandular structures in epithelial tissue).These cancers start in cells that make mucus to lubricate the inside of the colon and rectum.

Most of the colon cancers develop from these adenomas. There is a lag period of many years between the formation of anadenoma (polyp) and its development into a cancer. Thus if adenomatous polyps are picked up early and removed, then colon cancer can be prevented. If colon cancer is diagnosed early, then it is treatable. This has shown results in western countries, where making a screening colonoscopy compulsory in every individual after the age of 50has shown substantial reduction in mortality due to colon cancer.

In India, though the incidence is not so much as to mandate screening in everyone after a certain age, but incidence is increasing and there is a need for public to be aware of the high risk behavior and pre malignant conditions to achieve the same purpose.

Dr. Ajay Kumar, Chairman - Fortis Escorts Liver and Digestive Diseases Institute elaborates on the early symptoms, preventive measures and diagnosis of the silent killer.

Red flags which suggest need for screening for colon cancer:

• The presence of blood and mucus in the stools.
• Arecent unexplained change in bowel habits
• Unexplainedweight loss.
• Unexplained iron deficiency anemia
• Family history of colon cancer
• In addition patients suffering from IBD need to undergo surveillance colonoscopy.

Factors which might be responsible for Colon Cancer:

• Genes: Changes in the genetic material found in the cells which line the colon can cause colon cancer. These genetic changes are inherited from family members and increase the risk of developing the condition significantly. The most common form of hereditary colon cancer is 'Hereditary non-polyposis colorectal cancer syndrome' and 'familial adenomatous polyposis.'
• Lifestyle habits: A sedentary lifestyle which involves little or no exercise along with a diet which is low in fibers, high in red meat, processed meat and calories contribute to the formation of malignant polyps. Excessive consumption of alcohol and tobacco can also lead to the ingestion of carcinogenic material which can cause colon cancer.

• Age: Women above the age of 40 and men above the age of 50 are more prone to colorectal cancers.
• Ulcerative colitis, Crohn'sdisease are the common clinical conditions that predispose to Colon cancer and ask for surveillancecolonoscopy.

Preventive Measures:

While there is no way to prevent the occurrence of cancer, the risk associated with it can be lowered by:

• Maintaining one's weight on the lower side.
• Engaging in physical activity every day.
• Consuming fruits and vegetables instead of foods which are high in calorie intake.
• Limiting the consumption of red meat, processed meat, alcohol and tobacco.
• Ensure adequate intake of Vitamin D and Calcium.

In the Indian scenario, colorectal cancer stands fourth in men and third in women with respect to incidence and mortality rates. However, compared to the Western countries, colorectal cancer incidence rates are much lower in India. This low incidence in India,experts believe may be due to lower consumption of red and processed meat, high fibre intake and a lower prevalence of obesity in the country than in Western countries. Colon cancer is slightly more common than rectal cancer in the Western world, whereas, rectal cancer is more common in India.

Screening Options for Colon Cancer :

Polyps tend to gradually transform into cancers. Screening involves testing a patient for colorectal cancer in the early phase or in pre-cancerous stage, so that the mortality (death rate) of the disease can be lowered.

Various modalities for screening are :

• Stool tests pick up very minute quantities of blood. The common tests done are:
• Guaiac Fecal Occult blood test (G- FOBT).
• Fecal immunochemical test (FIT).
• FIT is the first option for detecting Fecal Occult Blood in CRC screening as there is no dietary restrictions required and the test is more sensitive.
• Fecal DNA analysis can also be done. This test identifies molecular alterations in adenoma and colorectal cancer cells.

• CT/MR colography.
• Invasive tests like Sigmoidoscopy and

There are false positives and negatives for every test. Out of these, colonoscopy is the best and preferred modality of screening, as physician can remove the polyps also at the same time.