Anorectal Melanoma

Anorectal Melanoma is a rare form of cancer that affects the anus and at times the rectum. Melanoma is a cancer developing from cells known as melanocytes. Melanocytes are responsible for melanin pigment production that gives colour to the skin. Such cells are present all over the body, inclusive of the skin, hair and in the cells that line the interior organs like the anus or rectum.

The third prevalent location for melanoma subsequent to the skin and eye is the anorectal area. But, it is still an atypical kind of cancer, constituting lesser than 1 in 100, i.e., one percent of all melanomas and in between 1-2% in 100 of all the anorectal cancers. Anorectal melanoma could affect many parts of the body like the rectum, anal canal – the connection between the anus and the rectum and even affects the anus. Majority of the individuals detected with anorectal melanoma are in the age groups of sixty to eighty years of age. It is also more prevalent among the female gender.

Anorectal Melanoma Causes

The precise cause for this atypical form of tumour is still unclear. Though there is awareness about the fact that being exposed to UV or ultraviolet rays arising from the sun or from tanning beds could raise the risk of getting melanoma of the skin. But, there is no apparent association in between being exposed to UV rays and developing anorectal melanoma.

Anorectal Melanoma Symptoms

• Many of these cancers are short of the normally occurring dark coloration linked with melanomas and are called as amelanotic. This could then become trickier to detect. Individuals are mostly given the initial treatment for piles (haemorrhoids).
• Symptoms could comprise of pain, bleeding from rectum, variation in bowel movement (diarrhoea or constipation), piles, mucous discharge, weariness and reduction of weight.
• All of the surfacing symptoms could additionally be due to several other bowel conditions.

Diagnosis & Tests:

• Generally, the doctor would do an exam of the back passage (rectal examination).
• In case the symptoms appearing are doubted to be due to cancer or there is uncertainty about what the problem could be, then the person could be referred to a specialist in a hospital.
• The specialist doctor would conduct a detailed physical examination that would involve performing a rectal exam wherein a lubricated gloved finger would be inserted via the rectal opening for palpating any lumps or swellings. This could cause slight discomfort though not painful. The doctor would additionally check for any kind of enlargement of the lymph nodes in the groin.

One might need to undergo certain additional tests stated below:

• Biopsy
  A tiny tissue sample could be removed from the dubious site and sent for microscopic examination. This procedure could be performed under the influence of local anaesthesia for de-sensitising the area. Excision biopsy procedure is generally conducted wherein the entire tumour is removed.
• Computerised tomography or CT scan
  A CT scan is done for taking a succession of x-rays for building 3-D images of the body. The scan causes no pain and would last for ten to thirty minutes on the whole. This test is done for checking whether the cancer has metastasized to other parts of the body like the liver, lungs or the brain.
• Magnetic Resonance Imaging or MRI scan
  This scanning technique employs magnetism rather than x-rays for producing a string of images of the interiors of the body. This test lasting for nearly thirty minutes is pain-free, though some might sense claustrophobia while the scanning is being done. The equipment emits a lot of noise during the procedure and ear muffs or headphones are offered for this reason.
• Chest X-rays
  A chest x-ray is generally conducted for checking if or not the cancer has metastasized to the lungs.
• Blood analysis
  Blood samples are drawn for checking the overall health conditions, the number of cells present in the blood or the blood count and for checking the functioning of the kidneys and the liver.

Staging:

The stage of the cancer is a terminology employed for describing the size and extent of spread from its initial location. Staging helps in recognizing the exact form and the staging of the cancer that aids in finalising the best course of treatment.

Cancer could metastasize to the blood stream or via the lymphatic system. The lymphatic system comprising of a net of lymph nodes are connected by fine ducts containing lymph nodes and bears some of the load of safeguarding the body from infection and ailments.

A widely employed staging system for melanoma is illustrated below:

• Stage 1A
  The cancer has not metastasized to the lymph nodes and is lesser than 0.75mm in thickness.
• Stage 1B
  The cancer limited to a small area has a thickness of 0.76 -1.5mm.
• Stage 2A
  The cancer is restricted to a specific area and having a thickness in between 1.5 -4.0mm.
• Stage 3
  The cancer has metastasized to the lymph nodes present in the groin and pelvic region or the lymph nodes located near the anus.
• Stage 4
  The cancer has metastasized to other regions of the body like the liver, lungs or the brain.

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