When the cells present in the rectum divide uncontrollably and form a tumor, it is referred to as rectal cancer or rectal carcinoma. The rectum forms the last few inches of the gastrointestinal tract.
Rectal cancer often starts with the growth of abnormal masses called polyps. Over time, these polyps become cancerous and lead to rectal cancer.
Rectal cancer is seen in both men and women, and its risk increases with age. Rectal cancer is commonly diagnosed among individuals who are 50 and older. Those with a positive family history of rectal cancer also have a higher chance of developing it. Lastly, in a few cases of rectal cancer, individuals have an inherited predisposition caused by certain genetic disorders.
Rectal cancer is one of the top ten common cancers globally. Nonetheless, its prevalence is relatively low in India.
A few reports in recent times have shown that the incidence of rectal carcinoma is increasing gradually, and the possible reasons for this include changed food habits, a sedentary lifestyle, and screening practices.
Rectal cancer and colorectal cancer are terms that are often used interchangeably. However, there is a slight difference between the two. Rectal cancer refers to the cancer of the rectum only, and colorectal cancer refers to the cancer of the colon and rectum, which are the parts of the large intestine.
Rectal cancer is classified into different types, based on the cell from which it originates. These rectal cancer types may present at both early and advanced stages, and their symptoms may vary depending on their type. The following are the various types of rectal cancer:
Adenocarcinoma forms in glandular cells that line the inner walls of the rectum, and it is the most common type of rectal cancer, accounting for over 95% of rectal cancers.
Carcinoid tumors of the rectum form in the neuroendocrine cells of the rectum. These cells produce specific hormones, and when the tumor becomes larger, these hormones are released into the bloodstream, causing various symptoms. These are further classified into typical and atypical carcinoid tumors. While typical carcinoid tumors are slow-growing and benign, atypical carcinoid tumors are fast-growing and cancerous.
Carcinoid tumor is one of the less common rectal cancer types.
Lymphoma or rectal lymphoma forms in the lymph tissue of the rectum. Rectal lymphoma is rare and often seen among those with immune-deficiency diseases. This type of rectal cancer is commonly seen among older individuals and is also one of the less common rectal cancer types.
Gastrointestinal stromal tumors (GISTs) of the rectum form in the interstitial cells of Cajal, which are the specialized cells present in the gastrointestinal tract. These cells are predominantly present in the stomach and small intestine and are scarcely present in the colon and rectum.
In some cases, rectal carcinomas develop due to an inherited predisposition. Having genetic conditions like familial adenomatous polyposis (FAP) and hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome, can increase one’s risk of developing rectal cancer.
These are the various types of rectal cancer. Rectal cancers are treated best when they are diagnosed in the early stages. Being mindful of the early signs of rectal cancer and opting for regular screening can help in effectively managing rectal cancer.
Rectal cancer staging is done to determine the progression of the disease. The rate at which rectal cancer progresses depends on its type – some rectal cancer types progress more rapidly, while others have a slower growth rate. Rectal cancer staging will also help doctors make better treatment decisions. The following are the different stages of rectal cancer.
Rectal cancer is confined to the inner lining of the rectum and has not spread to the underlying tissues.
Rectal cancer has grown beyond the lining and started spreading to the rectum wall.
Rectal cancer has grown into the rectum wall and may have spread to nearby tissues.
Rectal cancer has spread to the nearby lymph nodes.
Rectal cancer has advanced significantly and spread to distant organs in the body.
Rectal cancer staging is done through various diagnostic procedures, namely PET/CT scan, ultrasound scan, and biopsy.
Those experiencing persistent symptoms related to rectal cancer, especially rectal bleeding, changed bowel habits, abdominal pain, and unintended weight loss, should consult a doctor for a proper evaluation. Also, those with a family history of rectal carcinoma should consider regular screening. This can help in the early detection and timely treatment of rectal carcinoma.