Colorectal Cancer

Colon cancer is a type of cancer that develops in the large intestine. The colon, the longest part of the large intestine which ends in the anus. Colon cancer is the fourth most common cause of death due to cancer globally and ranks in the top 10 among causes of death due to cancer among Indians, according to the Indian Council of Medical Research.

Types Of Colon Cancer

Adenocarcinoma: Tumour that originates from cells in the lining of the gut that secretes mucus and other fluids.
Gastrointestinal Stromal Tumours (GIST): These are tumours that start in the muscle tissue of the digestive tract.
Lymphoma: These tumours start in the lymph nodes which are part of the body’s immune system.
Carcinoids: These are tumours that start in special hormone-producing cells in the intestine
Rarer syndromes involved with colorectal tumours: Turcot Syndrome, Peutz-Jeghers Syndrome, Familial Colorectal Cancer, Juvenile Polyposis Coli.
This classification can be determined by the pathologist based on the sample taken during surgery or colonoscopy.

Staging Of Colorectal Cancer

If you are diagnosed with colorectal cancer, your doctor or cancer oncologist will run more tests to determine the extent (stage) of your cancer. The stage of your cancer is based on the size and spread of the tumour and helps your doctor or cancer oncologist decide which treatments are optimum.

• Stage 0: The cancer is in its earliest stage and has not grown beyond the inner layer of the colon or rectum (carcinoma in-situ or intramucosal carcinoma)
• Stage I: The cancer has grown through the innermost layer into the second or third layer of the colon or rectum but has not spread to nearby lymph nodes or other organs in the body.
• Stage II: It is divided in to three subgroups: Stage IIA (The cancer has grown to the outermost layers of the colon or rectum but has not gone through them and has not spread to nearby organs, lymph nodes or other organs in the body), Stage IIB (The cancer has grown through the wall of the colon or rectum but has not grown into other nearby tissues or organs, nearby lymph nodes, or other organs in the body), Stage IIC (The cancer has grown through the wall of the colon or rectum and is attached to or has grown into other adjacent tissues or organs but has not yet spread to nearby lymph nodes or to other organs in the body.
• Stage III: It is also subdivided in to three subgroups: Stage IIIA (The cancer has grown through the layers of the colon or rectum and has spread to nearby lymph nodes but not to distant organs), Stage IIIB (The cancer has grown into the outermost layers of the colon or rectum and has spread to nearby lymph nodes but has not reached nearby tissue and distant organs), Stage IIIC (The cancer has grown into the outermost layers of the colon or rectum but has not reached nearby organs or distant site but has spread to 7 or more nearby lymph nodes).
• Stage IV: It is subdivided in to three subtypes: Stage IVA (The cancer may or may not have grown through the wall of the colon or rectum, to the nearby lymph nodes but has spread to a distant organ (e.g. liver, lung, distant lymph nodes), Stage IVB (The cancer may or may not have grown through the wall of the colon or rectum, spread to nearby lymph nodes but has spread to more than one distant organ not including the lining of the abdominal cavity), Stage IVC (The cancer may or may not have grown through the wall of the colon or rectum, spread to nearby lymph nodes and distant organs but has spread to the lining of the abdominal cavity).

Sources: European Society for Medical Oncology (ESMO); American Cancer Society; ICMR; Stanford Health.