Colon cancer, also known as bowel cancer or colorectal cancer or cancer of the bowel, is the cancer of large intestine (lower part of the digestive system). Majority of colon cancer cases start as small and non-cancerous clumps of the cells known as adenomatous. After a certain period of time, these polyps become colon cancers.
Adenocarcinoma is considered as the most common type of colon cancer. This type of colon cancer begins in the inner layer that spreads deep into the other layers. Adenocarcinoma can be further categorized into two subtypes that include –
Gastrointestinal Stromal Tumors : This is considered as a rare type of colon cancer that begins in a cell found in the gastrointestinal tract lining known as interstitial cells of Cajal (ICCs). These type of tumors are classified as sarcomas that include cartilage, fat, bones, blood vessels, deep skin tissues, muscle and nerves.
Squamous Cell Carcinomas: Certain portions of the gastrointestinal tract such as the end of the anus and the upper part of the esophagus are lined with squamous cells. Squamous cell carcinomas are those cancers that begin in these cells.
Leiomyosarcomas: This type of cancer typically means- cancer of smooth muscle. This is considered as a rare type that account for only 0.1% of all colon cancer cases.
Gastrointestinal Carcinoid Tumors: This type of colon cancer is considered as a slow-growing cancer that develops in the neuroendocrine cell in the GI tract lining.
Melanomas: This type is primarily related with skin but can also happen anywhere that include recturm or colon.
Primary Colorectal Lymphomas: The cancers that grow in the lymphatic system of cells (lymphocytes) are known as lymphomas. Primary colorectal lymphomas develop in the later stages of life and are more commonly seen in men as compared to women.
The uncontrollable growth of cells that do not die causes cancer. There is a normal cycle of growth, division and death in case of normal cells but colon cancer do not experiences this type of normal cycle and continue to grow and divide. There are no as such known causes of colon cancer.
The early symptoms of colon cancer include –
Sometimes bleeding happens when the colon cancer progresses. Gradually, there will be not enough red blood cells in the body that is called as anemia. Following are some of the symptoms of anemia –
Also obstruction is caused by the colon cancer that include following symptoms –
Stage 1: In the first stage, cancer has not spread further than the original tumor.
Stage 2: The second stage is marked by the growth of tumors through the bowel wall that are close to the tissues. However, this growth has not spread to any part of the body.
Stage 3: In the third stage, there are tumor cells close to the lymph nodes.
Stage 4: The last stage is marked by the spread of the tumor to other parts of the body.
A number of tests are performed for diagnosing colon cancer that include –
Certain other tests are also required for finding the cancer cells that have spread inside the rectum and colon or possibly to other body parts that include –
There are six treatment options for colon cancer that include –
Targeted Therapy : Certain substances and drugs are used by the targeted therapy in order to target particular cancer cells without causing any harm to nearby normal cells. The two types of targeted therapy include –
Chemotherapy: Certain types of drugs are used for stopping the growth of cancer cells or for destroying the cancer cells. The injection of these drugs is done into a vein from where they enter the bloodstream and they then travel through the entire body.
Radiation Therapy: High-energy beams are used for destroying cancer cells. Internal radiation and external radiation are the two types of radiation therapy. A radioactive substance that is sealed in catheters, needles wires or seeds is placed close to the cancer in the case of internal radiation. On the other hand, linear accelerators outside the body are used for sending radiation to the cancer in the case of external radiation. The type of radiation depends on the stage and type of the cancer.
Surgery: The surgical procedure involves the removal of diseased segment with sufficient margins, surrounding lymph nodes and tissue. Following are some of the types of surgeries performed –
Sometimes chemotherapy or radiation therapy is provided after surgery in order to shrink the tumor. This makes the removal of the tumor easy while simultaneously lessening the problems associated with bowel control after surgery. Neoadjuvant therapy is the name given to the treatment that is given before the surgery.