Anal cancer is really a disease by which malignant (cancer) cells form within the tissues of the anus. The anus is the end of the large intestine, below the rectum, through which stool (solid waste) leaves the body. The anus is formed partly from the outer, skin layers from the body and partly from the intestine. Two ring-like muscles, called sphincter muscles, enter and exit the anal opening to let stool pass out of the body. The anal canal, the part of the anus between the rectum and the anal opening, is all about 1½ inches long.
Anatomy from the lower digestive tract, showing the colon along with other organs.
The skin round the outside the anus is called the perianal area. Tumors in this area are skin tumors, not analcancer.
Being have contracted the human papillomavirus (HPV) can impact the risk of developing anal cancer.
Kinds of anal cancer
Squamous cell cancer
About 9 from 10 (90%) anal cancers are squamous cell cancers, sometimes called epidermoid cancers.
You will find 3 kinds of squamous cell anal cancer
* Large cell keratinising
* Large cell non keratinising (also called transitional)
Non keratinising and basaloid cancers are sometimes grouped together as ‘cloacogenic’ anal cancer. A keratinising cancer has keratin (the protein that forms hair and nails) within the cancer cells. This kind of anal cancer starts in the transitional zone from the anal canal, in which the squamous cells satisfy the glandular cells. All the squamous cell types of anal cancer are treated just as.
Non epidermoid cancer
The other 1 out of 10 anal cancers (10%) are adenocarcinoma, small cell cancers, ‘ undifferentiated’ cancers (referred to as basaloid cancers) and melanomas. This group is called non-epidermoid cancers. They behave differently to squamous cell anal cancers, therefore the treatment is different.
Cancers that start in the anal margin, usually look a lot more like normal cells (they're ‘ well differentiated’). Anal margin tumours are more common in males than women. Cancers that start higher up within the anal canal tend to be more common in women.
This is a rare type of anal cancer that affects the glandular cells that produce mucus in the anal canal. Only 5% of anal cancers are this type. This kind of anal cancer is treated in the same way as rectal cancer. Basal cell carcinoma
This can be a kind of cancer of the skin and it develops in the region around the anus. You can find information about treating basal cell cancers in the skin cancer portion of CancerHelp UK.
This is another type of cancer of the skin. These cancers develop from the cells that produce melanin, the pigment or colour for that skin. Treatment methods are the same as for other melanomas.
Diagnosis of Anal Cancer
Possible signs of anal cancer include bleeding in the anus or rectum or a lump close to the anus.
These along with other symptoms might be caused by anal cancer. Other conditions could cause exactly the same symptoms. A physician ought to be consulted if any of the following problems occur: -
* Bleeding from the anus or rectum.
* Pain or pressure in the area around the anus.
* Itching or discharge from the anus.
* A lump near the anus.
* A change in bowel habits.
Tests that examine the rectum and anus are used to detect (find) and diagnose anal cancer.
The following tests and procedures can be utilized: -
* Physical exam and history: An exam of the body to check on general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. Past the patient’s health habits and past illnesses and treatments will also be taken.
* Digital rectal examination (DRE): - A test of the rectum and anus. A doctor or nurse inserts a lubricated, gloved finger to the lower part of the rectum to feel for lumps or anything else that seems unusual.
* Anoscopy: - A test from the anus minimizing rectum using a short, lighted tube called an anoscope.
* Proctoscopy: - A test of the rectum using a short, lighted tube called a proctoscope.
* Endo-anal or endorectal ultrasound: - A process in which an ultrasound transducer (probe) is inserted into the anus or rectum and used to bounce high-energy sound waves (ultrasound) off internal tissues or organs making echoes. The echoes form a picture of body tissues called a sonogram.
* Biopsy: - The removal of cells or tissues so they can be viewed within microscope by a pathologist to check on for signs of cancer. If an abnormal area is seen during the anoscopy, a biopsy might be done in those days.