Colorectal Cancer: Cancer of the Colon and Rectum

What is Colorectal Cancer?

Colorectal Cancer (Carcinoma) is a malignant neoplasm of the large intestine that affects the colon and rectum. Carcinoma of the colon is cancer usually starts as small, benign clumps of cells in the colon and rectum’s inner lining. These are called polyps, but not all polyps become cancerous.

The two main types of polyps are:

·        Adenomatous polyp: The adenomatous polyp sometimes turns cancerous, so the adenomas are known as a pre-cancerous condition.

·        Hyperplastic polyp and inflammatory polyp: These types of polyps are non-cancerous in general and are very common too.

Polyps that can turn cancerous are usually larger than 1 centimeter. If the number of polyps found is three or more than three, then these are prone to become cancerous. Colorectal carcinoma can also be called colon cancer or rectal cancer, depending on the region of origin ( colon or rectum). Both types are often clubbed together as they show similar symptoms and are treated similarly.

The incidence rates of colorectal cancer in India is estimated to be 4.2 per 100,000 males and 3.2 per 100,000 females.

This is very much lower when compared to the incidence rates in the United States. Although old people are more susceptible to developing colorectal carcinoma, recent years have witnessed a rise in the number of young patients.

Types

Colorectal Carcinoma Types:

• Most colorectal cancers are adenocarcinomas. This type of cancer arises from the epithelial cells of the colorectal mucosa. It starts as a polyp called adenoma and eventually develops into cancer. It is further subdivided into lesser-known types as follows :
• Mucinous adenocarcinoma – It is made up of mucous that causes the cancer cells to spread rapidly and become more aggressive.
• Signet ring cell adenocarcinoma – It is aggressive and difficult to treat.
• Gastrointestinal carcinoid tumors – These tumors develop in the nerve cells called neuroendocrine cells. They are slow-growing and develop in the lungs or gastrointestinal tract.

Other rare and uncommon types of colorectal carcinoma are :

• Gastrointestinal stromal tumors – It starts from the interstitial cells of Cajal present in the colon’s walls and may be benign. It can occur anywhere in the digestive tract, especially in the stomach, small intestine, and rectum. It is not often found in the colon.
• Primary colorectal lymphoma – It is a rare type of non-Hodgkin’s lymphoma that affects the gastrointestinal tract and develops later in life. It is more common in men than in women.
• Leiomyosarcomas – It typically begins in the smooth muscle layer in the walls of the colon and rectum. It mostly develops in the abdomen.

Stages

What are the stages of Colorectal Cancer?

Based on the extent to which cancer has spread, colorectal carcinoma is categorized into different stages as follows :

• Stage 0 (Cancer in situ ) – Cancer cells are localized to the colon and rectum’s mucosa or inner lining.
• Stage I – cancer has spread to the muscular layer of the colon and rectum walls but not to the nearby tissues and lymph nodes.
• Stage II – Cancer has grown through all the three layers of the walls of the colon and rectum but not the nearby lymph nodes and tissues.
• Stage III – Cancer has spread to at least 1 to 3 lymph nodes and to the nearby tissues but not to the body’s distant parts.
• Stage IV – Cancer has spread to the distant part of the body like the liver or lungs.

Recurrent colorectal carcinoma – Relapse or recurrence of cancer in the colon, rectum, or any other part of the body after treatment of the initial tumor.

Symptoms

Colorectal Cancer Symptoms:

The initial symptoms of colorectal carcinoma are non-specific. The symptoms are as follows :

· Change is the usual pattern of bowel habit, especially in a patient over forty years old

· Recent onset of constipation, diarrhea, or tenesmus in older patients.

· Bright red or dark blood in the stool.

· Weakness and constant fatigue

· Unexplained weight loss

· Sleeplessness

· Stools that appear narrower than usual

· Frequent gas pain

· Bloating

· Fullness

· Cramps

· Discomfort in the stomach

· Constant urge to pass stool.

Causes

What Causes Cancer of Colon?

The exact cause of colorectal cancer is not known, but it is believed that mutations in the DNA result in the development of colorectal carcinoma. These mutations may cause abnormal cells to accumulate and form polyps in the lining of the colon. Untreated polyps are often associated with cancer, and so these are often removed using surgery to reduce the risk of colorectal cancer.

Risk factors

Colorectal Cancer Risk Factors

The risk factors that may increase the chances of carcinoma developing colorectal cancer are :

·        Age – Older adults, especially people older than 50, are at a higher risk than young adults and teenagers.

·        Race – Afro-Americans and black people are at higher risk irrespective of their gender.

·        Family history – The risk of developing colorectal cancer is higher if any first-degree relative of the patient has a history of colorectal polyp or cancer or colorectal cancer.

·        Gender – Men are more likely to develop colorectal cancer when compared to women.

·        Diet – Food with high-fat content, less fiber, and consumption of more red meat and processed meat is associated with higher risk.

·        Physical activity – Sedentary lifestyle and lack of physical activity are found to increase developing colorectal carcinoma. (Read more: Physical Inactivity: How does it affect humans?)

·        Diabetes – People with type 2 diabetes are more likely to develop colorectal carcinoma than non-diabetic patients. (What is Diabetes Mellitus?)

·        Obesity – Overweight and high body mass index are also found to increase the risk factor. (High BMI- An early indicator of health risk)

·        Smokers – People who smoke are at higher risk of developing colon cancer, especially men, as tobacco is found to facilitate DNA damage and mutate healthy cells.

·        Alcohol Consumption – Moderate to heavy consumption of alcohol increases the risk as the metabolism of alcohol involves the conversion of ethanol to its metabolites, and this is found to exert a carcinogenic effect on the colon.

·        History of cancer – Patients who have already had colorectal cancer are more likely to get recurrent colorectal cancer. Women with ovarian cancer or uterine cancer are also at a higher risk.

·        Genetic conditions – Individuals with certain rare inherited conditions like Lynch syndrome, Juvenile polyposis syndrome, Gardner syndrome, Familial adenomatous polyposis, and Turcot syndrome are at a higher risk. These causes genetic mutations of the healthy cells.

·         Other conditions – People with inflammatory bowel disease such as ulcerative colitis or Crohn’s disease develop chronic inflammation of the colon, increasing the risk.

Diagnosis

Diagnosis and Screening of colorectal carcinoma

The doctor recommends the following tests and examinations for the diagnosis of colorectal carcinoma :

• Physical examination – The signs and symptoms manifested by the patient are examined. The most common signs of colorectal carcinoma are lethargy, low-grade fever, pallor, abnormally thin body, discomfort on palpitation, rectal bleeding, and jaundice. Rectal exams are also done as a part of the physical examination.
• Colonoscopy – This method allows the doctor to view the inside of the entire colon and rectum. During this procedure, a thin, long tube called a colonoscope is inserted into the rectum after proper sedation of the patient. It can also be used for removing polyps and other tissues for biopsy.
• Biopsy – A small tissue from the tumor is removed and sent to the pathologist for microscopic examination to confirm the presence of colorectal cancer. The tissue is collected either by using colonoscopy or by performing needle biopsy under the assistance of a CT scan or ultrasound.
• Molecular testing of the tumor – Colorectal cancers is characterized by mismatch repair proteins, which is called mismatch repair defect. Molecular testing of the tumor is done to confirm if the patient has Lynch syndrome or not and check if immunotherapy can be used as a treatment of choice in the patient. This diagnostic procedure involves using predictive biomarkers to predict the response to a specific treatment or therapy.
• Blood tests – People with colorectal cancer often experience rectal bleeding, resulting in low levels of red blood cells in complete blood count. Another test that is often done to diagnose and monitor the patients under treatment is the CEA test. The CEA test or carcinoembryonic antigen test is used to detect this antigen’s levels in the blood as this antigen is found in high levels in most of the metastasized colorectal cancer patients.
• Computed Tomography (CT) scan – X-rays are used to provide detailed 3-dimensional images of the colon and rectum to detect any abnormality and measure the tumor size. Sometimes, a contrast dye is injected intravenously before the test to get a much clearer image and check the metastasis of colorectal cancer.
• Magnetic resonance imaging (MRI) – Magnetic fields are used to measure the tumor size, identify its location in the colon or rectum, and provide detailed images of the colon and rectum.
• Endorectal ultrasound – Sound waves are used to determine how deeply cancer has grown and for determining the treatment choice. However, it cannot detect if cancer has spread to the lymph nodes or beyond the pelvis.
• Chest x-ray – Radiations are used to create images of the lungs to check if cancer has spread to the lungs or not.
• Positron emission tomography (PET) scan – A small amount of radioactive sugar accumulated at the cancer cells is injected into the patient’s body. The cancer cells are detected using scanners that capture images of the regions in the body where the radioactive sugar is concentrated. PET scan is often used in combination with a CT scan for detecting colorectal cancer.

Treatment

What is the Treatment of Colorectal Cancer?

A gastroenterologist, medical oncologist, radiation oncologist, and surgeon usually treat colorectal carcinoma in a patient. These doctors collaborate and suggest the most optimal treatment option for the patient, depending on their health and other medical conditions. The different treatments available for colorectal cancer are :

• Surgery – It is the most common method of treating colorectal cancer. It involves removing the tumor and a part of the healthy colon or rectum and nearby lymph nodes and is frequently known as surgical resection. Other commonly performed surgeries include laparoscopic surgery, which uses smaller incisions than surgical resection, colostomy for rectal cancer for patients with rectal cancer, and radiofrequency ablation or cryoablation waves to heat the tumors in the liver and lungs. (Read more about Types of Cancer Surgery )
• Radiation therapy – High energy x-rays are used in external-beam radiation therapy and stereotactic radiation therapy to treat metastasized colorectal carcinoma. It is usually given 5 days a week for several weeks and can also shrink the tumor’s size before surgery.
• Chemotherapy – drugs commonly used to destroy the cancer cells in colorectal carcinoma are fluorouracil, irinotecan, oxaliplatin, tipiracil, and capecitabine. These drugs are either used alone or in combination with other drugs for a specific number of cycles over a set period of time.
• Targeted therapy – In this therapy, specific cancer genes, proteins, and processes needed for the cancer cells’ growth and survival are targeted. Anti-angiogenesis therapy comes under this treatment as it stops forming new blood vessels that are needed to grow the cancer cells. Monoclonal antibodies used for this purpose are bevacizumab, regorafenib, and Ziv-aflibercept. Other agents used include epidermal growth factor receptors (EGFR) inhibitors like cetuximab and panitumumab. These block the EGFR that, in turn, stops the growth and proliferation of colorectal cancer. BRAF inhibitors like encorafenib are also used to treat cancer due to a mutation of the BRAF gene. (Read more: Personalized Medicine: Targeted Treatment for better Patient Outcome)
• Immunotherapy – Immune checkpoint inhibitors like pembrolizumab, nivolumab, and a combination of nivolumab and ipilimumab are used to stop the growth and survival of colorectal cancer. These target receptors on the tumor cells and make the tumor cells more susceptible to the immune cells. It is frequently used to treat metastatic colorectal cancer.

Managing Lifestyle

Lifestyle changes to reduce the risk of colorectal cancer:

· Eat healthy food that is rich in fiber.

· Avoid fatty food.

· Avoid alcohol or limit consumption in moderation.

· Exercise regularly.

· Maintain a healthy weight.

· Managing diabetes and keeping sugar levels in check.

· Decreasing the amount of red meat consumed regularly.

· Get yourself screened for cancer if any symptoms manifest.

· Get a colonoscopy, and other cancer screening tests are done after 50 as a preventive measure.

FAQs

 Is it curable?

It is highly curable and treatable in the initial stages when the cancer is localized to the colon. The chances of complete recovery reduce with stage III and stage IV colorectal cancer.

What are the survival rates of colorectal carcinoma?

The average 5-year survival rate for colorectal carcinoma is 64 %, while that for localized colorectal carcinoma is 90 %. The survival rates for stage II tumors range from 55 to 80 %, while that for stage III and stage IV tumors are estimated to be 40 % and 10 %, respectively.

What is the cost of treatment of colorectal carcinoma in India?

The average cost of surgery is estimated to be 3.5 lakhs, and that of radiation therapy is approximately 3 to 4 lakhs. Each cycle of chemotherapy costs around Rs.20000 to Rs.40000, depending on the drug of choice.

Is rectal bleeding a sign of colorectal cancer?

Bright red blood in the toilet paper following bowel movement or red or pink water along with the stool is a sign of colorectal cancer. Rectal bleeding usually occurs due to bleeding in the lower colon or rectum and is a common sign of colorectal cancer.

Do age and gender play a role?

Men are more likely to get colorectal cancer than women. People over 50 years of age are at a higher risk of developing colorectal cancer, but young adults can also develop this cancer.

Is colorectal cancer genetic?

A small number of colorectal cancer cases are inherited, and this is often associated with other genetic conditions like Gardner syndrome, familial adenomatous polyposis, and Lynch syndrome.

Cancer Hospitals

Cancer Hospitals in India

1. Asian Institute of Oncology
2. S.L.Raheja Hospital, Raheja Hospital Road, Mahim, Mumbai 
3. Cancer Institute (WIA),  Adyar, Chennai
4. Jaslok hospital research Centre, Mumbai
5. Dharamshila Cancer Hospital & Research Centre, Vasundhara Enclave, New Delhi
6. Dr. B. Borooah Cancer Institute, Gopinath Nagar, Guwahati
7. Dr. Rai Memorial Cancer Institute 562, Anna Salai, Chennai, Tamil Nadu
8. Rajkot Cancer Society, Mr. N.P. Cancer Institute, Raiya Road, Rajkot, Gujarat
9. Regional Cancer Centre, Medical College Campus, P.B.2417, Thiruvanthapuram , Kerala.
10. Tata Memorial Centre, Dr. Ernest Borges Marg, Parel, Mumbai
11. The Gujarat Cancer & Research Insitute, M.P. Shah Cancer Hospital, New Civil Hospital Compound Asarwa, Ahmedabad
12. Rajiv Gandhi Cancer Hospital & Research Institute, Sector 5, Rohini, Delhi
13. Bhagwan Mahaveer Cancer Hospital & Research Centre, Jawaharlal Nehru Marg, Jaipur

Other reputed Cancer Hospitals and Institutes in India:

1. Regional Centre for Cancer Research, Adyar, Chennai.
2. Regional Centre for Cancer Research and Treatment, Mangalabag, Cuttack – 753 007.
3. Rotary Cancer Centre, 117/K/11, Gutaiya, G.T.Road, Kanpur  – 208 002, India
4. Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Sector 22, Kharghar, Navi Mumbai – 410 210
5. Amala Cancer Research Centre, Amalangar, Trichur.
6. Bose Institute
7. Cancer Treatment & Research Centre, Lion District 324 C-1, Seethammadhara North Extn., Visakhapatnam – 530 013 (AP).
8. Chittaranjan Cancer Institute, 37, S.P. Mukherjee Road, Kolkata 700026
9. Christian Cancer Centre, Kakinada Pithapuram Road, Kakinada – 533 003, Andhra Pradesh
10. All India Institute of Medical Sciences, Ansari Nagar, New Delhi – 110016.
11. Dr. Bhubaneshwar Barooah Cancer Institute, Gopinath Nagar, Guwahati – 781 016, Assam.
12. G.V.N. Cancer Centre, No.16, Kiledar Street, Tiruchirapalli – 620 002, Tamil Nadu.
13. Goa Cancer Society, GM Cancer Hospital & Research Institute, Dr. E. Borges Road, Dona Paula – 403 004, Goa.
14. Indian Rly. Cancer Institute & Research Centre, N.E. Railway, Lahartara, Varanasi – 221 002, Uttar Pradesh.
15. Institute of Cytology & Preventive Oncology, I-7, Sector 39, P.O.Box No. 544, Near Degree College, Opposite City Centre, Noida – 201 301, Uttar Pradesh.
16.  International Cancer Centre,  Neyyoor,  Tamilnadu  – 629 802.
17. International Network for Cancer, Treatment, & Research Room No. 127A, Sir Gangaram Hospital, Rajinder  Nagar, New  Delhi -110 060.
18. J.K. Cancer Institute (C.S.V.M. Medical College), Kanpur  – 208 002, Uttar Pradesh.
19. Jagdish Cancer & Research Centre, 3-6-20, Tirumala Apts. Skyline Lane, Basheer Bagh, Hyderabad.
20. Jawaharlal Nehru Cancer Hospital, & Research Centre, Idgah Hills, PB No. 32 Bhopal – 462 001.
21. Mohan Das Oswal Cancer Treatment & Research Centre, G.T. Road, Sherpur, Ludhiana – 141 009, Punjab.

Cancer Specialists

Top 20 Cancer Specialists in India

1. Dr. Suresh H. Advani
2. Dr. Harit Chaturvedi
3. Dr. Kapil Kumar 
4. Dr. Ashok Vaid
5. Dr. Aruna Chandrasekhran
6. Dr. Rajesh Mistry
7. Dr. S Hukku
8. Dr. Bidhu K Mohanti
9. Dr. Vinod Raina
10. Dr. Sabyasachi Bal
11. Dr. Hari Goyal
12. Dr. Tejinder Kataria
13. Dr. Rajesh Jindal
14. Dr (Col.) R Ranga Rao
15. Dr. Jyoti Wadhwa
16. Dr. Sandeep Mehta
17. Dr. Sunil Kumar Gupta
18. Dr. Sankar Srinivasan
19. Dr. PL Kariholu
20. Dr. Subodh Chadra Pnndea