Introduction
Colorectal cancer is a type of cancer that affects the large intestine, which consists of the colon and the rectum. It can cause symptoms such as blood in the stool, abdominal pain, weight loss, and fatigue. Colorectal cancer can be prevented by regular screening and healthy lifestyle. Colorectal cancer can be treated by surgery, radiation, chemotherapy, and other methods, depending on the stage and location of the tumor.
Prevalence
Colorectal cancer is the seventh most common cancer in India, with about 27,605 new cases and 19,548 deaths in 2018. It affects both men and women, but it is more common in older people. The average age of diagnosis is around 40-45 years.
The exact cause of colorectal cancer is not known, but some factors can increase the risk of developing it. These factors include:
Age: The risk of colorectal cancer increases with age. Most cases occur in people older than 50 years.
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Diet: Eating a lot of red meat, processed meat, and animal fat can increase the risk of colorectal cancer. Eating a lot of fruits, vegetables, and fiber can lower the risk.
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Obesity: Being overweight or obese can increase the risk of colorectal cancer by affecting hormones and inflammation.
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Smoking: Smoking tobacco can increase the risk of colorectal cancer by damaging the DNA of the cells in the colon and rectum.
Alcohol: Drinking alcohol can increase the risk of colorectal cancer by affecting the metabolism and absorption of nutrients.
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Physical activity: Being physically inactive can increase the risk of colorectal cancer by affecting the bowel movement and immune system.
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Inflammatory bowel disease: Having a chronic inflammation of the intestines, such as Crohn’s disease or ulcerative colitis, can increase the risk of colorectal cancer by causing abnormal cell growth.
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Family history: Having a close relative who had colorectal cancer or polyps can increase the risk of colorectal cancer by inheriting genetic mutations that predispose to it.
Polyps
Colorectal cancer usually develops from a benign growth called a polyp that forms on the inner lining of the colon or rectum. Polyps are usually harmless, but some types can become cancerous over time. The most common type of polyp that can turn into colorectal cancer is called an adenoma. Adenomas can grow slowly or rapidly, depending on their genetic makeup. Adenomas can become cancerous when they acquire mutations in their DNA that make them grow uncontrollably and invade other tissues.
Diagnosis & Prevention
The best way to prevent colorectal cancer is to detect and remove polyps before they become malignant. This can be done by undergoing regular screening tests that examine the colon and rectum for any abnormality. Screening tests include:
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Faecal occult blood test (FOBT): This test checks for traces of blood in the stool that may indicate bleeding from polyps or tumors. This test should be done every year after age 45.
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Sigmoidoscopy: This test uses a thin flexible tube with a light and a camera to look at the lower pa
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Colonoscopy: This test uses a longer version of the sigmoidoscopy tube to look at the entire colon and rectum for any polyps or tumors. This test also allows for removing any polyps that are found during the procedure. This test should be done every 5 years after age 50.
Screening tests can reduce the incidence and mortality of colorectal cancer by finding and removing precancerous polyps and detecting early-stage tumors that are more treatable.
The diagnosis of colorectal cancer is confirmed by taking a sample of tissue from the suspected tumor and examining it under a microscope. This is called a biopsy and it can be done during a sigmoidoscopy or colonoscopy. The biopsy can also determine the type, grade, and stage of the cancer.
Treatment
The treatment of colorectal cancer depends on many factors, such as the type, grade, stage, location, and molecular characteristics of the tumor, as well as the overall health and preferences of the patient. The main treatment options for colorectal cancer are:
Surgery: This is the primary treatment for most cases of colorectal cancer. Surgery involves removing the tumor and some surrounding healthy tissue to ensure complete removal. Surgery can also remove any lymph nodes that may be affected by the cancer.
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Radiation therapy: This is the use of high-energy rays or particles to kill cancer cells or shrink tumors. Radiation therapy can be used before surgery to shrink large tumors or after surgery to kill any remaining cancer cells. Radiation therapy can also be used to relieve pain or bleeding in advanced-stage colorectal cancer.
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Chemotherapy: This is the use of drugs that kill rapidly dividing cells, such as cancer cells. Chemotherapy can be used before surgery to shrink large tumors or after surgery to kill any remaining cancer cells. Chemotherapy can also be used to slow down or stop the growth of metastatic colorectal cancer.
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Targeted therapy: This is the use of drugs that target specific molecules that are involved in the growth and survival of cancer cells. Targeted therapy can be used alone or in combination with chemotherapy to treat metastatic colorectal cancer that has certain genetic mutations or markers.
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Immunotherapy: This is the use of drugs that stimulate the immune system to recognize and attack cancer cells. Immunotherapy can be used alone or in combination with chemotherapy to treat metastatic colorectal cancer that has certain genetic mutations or markers.
Prognosis
The prognosis of colorectal cancer depends on many factors, such as the type, grade, stage, location, and molecular characteristics of the tumor, as well as the age, health, and response to treatment of the patient. In general, colorectal cancer has a better prognosis if it is detected early and treated promptly. The five-year survival rate for colorectal cancer in India was around 50% in 2018.
Acknowledgement
Author
Dr Nikhil Nanjappa M.S., FRCS Ed., M.IPD Ed.,M. FST Ed., has recently returned from the United Kingdom after serving as a Consultant Surgeon at St. James’s University Hospital, Leeds. He is a consultant surgical gastroenterologist and a colorectal surgeon. He is amongst only a handful of surgeons in the country with 3 years of super speciality training experience in colorectal surgery. He has extensive experience and is trained in advanced minimally invasive techniques for the management of haemorrhoids, fissures and fistulas.
For appointments visitwww.drnikhilnanjappa.com or call +91081 27867