Anal Cancer Causes, Symptoms, Diagnosis, Treatment, Prevention

Anal Cancer Causes, Symptoms, Diagnosis, Treatment, Prevention


What Is Anal Cancer?


Anal cancer occurs in the anus, the end of the gastrointestinal tract. Anal cancer is very different from colorectal cancer, which is much more common. Anal cancer's causes, risk factors, clinical progression, staging and treatment are all very different from colorectal cancer. Anal cancer is a lump which is created by the abnormal and uncontrolled growth of cells in the anus. 

Anal cancer can cause signs and symptoms such as rectal bleeding and anal pain.

Anal cancer is very rare.  According to the American Cancer Society, approximately 5,070 new cases of anal cancers were diagnosed in the USA in 2008, of which about 60% were women. Most anal cancer patients are diagnosed in their early 60s. Approximately 680 people died from anal cancer in the USA in 2008. The USA has a population of 300 million (2009).

Most people with anal cancer are treated with a combination of chemotherapy and radiation. Though combining anal cancer treatments increases the chance of a cure, the combined treatments also increase the risk of side effects.

Who Gets Anal Cancer?


Most anal cancers (80%) are diagnosed in people who are over the age of 60. Prior to age 35, anal cancer is more common in men. However, after age 50, anal cancer is slightly more common in women.

The incidence rate of anal cancer is six times higher in single men as compared to married men.

Receptive anal intercourse is strongly related to the development of anal cancer.

Anal infection with human papillomavirus (HPV) resulting in genital warts is a major risk factor for the cancer.

Immunocompromised patients, such as those with HIV disease, are prone to get anal cancer. In this subgroup, the prognosis is worse, than for non-immunocompromised patients.

Gardasil, the HPV vaccine originally approved for the prevention of cervical cancer, was approved for the prevention of anal cancer in late 2010.

Read more:

Anal Fissures Causes, Symptoms, Diagnosis, Treatment, Prevention,Home Remedies

Causes of Anal Cancer


Anal cancer forms when a genetic mutation turns normal, healthy cells into abnormal cells. Healthy cells grow and multiply at a set rate, eventually dying at a set time. Abnormal cells grow and multiply out of control, and they don't die. The accumulating abnormal cells form a mass (tumor). Cancer cells invade nearby tissues and can separate from an initial tumor to spread elsewhere in the body (metastasize).

Anal cancer is closely related to a sexually transmitted infection called human papillomavirus (HPV). Evidence of HPV is detected in the majority of anal cancers. HPV is thought to be the most common cause of anal cancers.

What Are the Symptoms of Anal Cancer?


  • Rectal bleeding - the patient may notice blood on feces or toilet paper.
  • Pain in the anal area.
  • Lumps around the anus. These are frequently mistaken for piles (hemorrhoids).
  • Mucus discharge from the anus.
  • Jelly-like discharge from the anus.
  • Anal itching.

When to see a doctor 


Talk to your doctor about any signs and symptoms that bother you, especially if you have any factors that increase your risk of anal cancer.

How Is Anal Cancer Diagnosed?


Anal cancer nay be detected during a routine digital rectal exam or during a minor procedure, such as removal of what is believed to be a hemorrhoid.

The cancer may also be detected with more invasive procedures such as an anoscopy, proctoscopy, or endorectal ultrasound.

If cancer is suspected, a biopsy should be done and the specimen examined by a pathologist.

Staging workup should include an abdominal and pelvic CT scan or a pelvic MRI scan to assess the pelvic lymph nodes, a chest x-ray, and liver function studies. PET scanning is not necessary.

Certain factors affect the prognosis (chance of recovery) and treatment options


The prognosis (chance of recovery) depends on the following:


  • The size of the tumor.
  • Where the tumor is in the anus.
  • Whether the cancer has spread to the lymph nodes.

The treatment options depend on the following:


  • The stage of the cancer.
  • Where the tumor is in the anus.
  • Whether the patient has human immunodeficiency virus (HIV).
  • Whether cancer remains after initial treatment or has recurred.

Stages of Anal Cancer


After anal cancer has been diagnosed, tests are done to find out if cancer cells have spread within the anus or to other parts of the body.

There are three ways that cancer spreads in the body


The three ways that cancer spreads in the body are:

  • Through tissue. Cancer invades the surrounding normal tissue.
  • Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
  • Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.
When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.

The following stages are used for anal cancer:

Stage 0 (Carcinoma in Situ)


In stage 0, abnormal cells are found in the innermost lining of the anus. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.

Stage I


In stage I, cancer has formed and the tumor is 2 centimeters or smaller.

Stage II


In stage II, the tumor is larger than 2 centimeters.

Stage IIIA


In stage IIIA, the tumor may be any size and has spread to either:

  • lymph nodes near the rectum; or
  • nearby organs, such as the vagina, urethra, and bladder.

Stage IIIB


In stage IIIB, the tumor may be any size and has spread:

  • to nearby organs and to lymph nodes near the rectum; or
  • to lymph nodes on one side of the pelvis and/or groin, and may have spread to nearby organs; or
  • to lymph nodes near the rectum and in the groin, and/or to lymph nodes on both sides of the pelvis and/or groin, and may have spread to nearby organs.

Stage IV


In stage IV, the tumor may be any size and cancer may have spread to lymph nodes or nearby organs and has spread to distant parts of the body.

What is the treatment options for anal cancer?


There are different types of treatment for patients with anal cancer


Different types of treatments are available for patients with anal cancer. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

Three types of standard treatment  for Anal Cancer are used:


Radiation therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. The way the radiation therapy is given depends on the type and stage of the cancer being treated.

Chemotherapy

Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the spinal column, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). The way the chemotherapy is given depends on the type and stage of the cancer being treated.

Surgery

Local resection: A surgical procedure in which the tumor is cut from the anus along with some of the healthy tissue around it. Local resection may be used if the cancer is small and has not spread. This procedure may save the sphincter muscles so the patient can still control bowel movements. Tumors that develop in the lower part of the anus can often be removed with local resection.

Abdominoperineal resection: A surgical procedure in which the anus, the rectum, and part of the sigmoid colon are removed through an incision made in the abdomen. The doctor sews the end of the intestine to an opening, called a stoma, made in the surface of the abdomen so body waste can be collected in a disposable bag outside of the body. This is called a colostomy. Lymph nodes that contain cancer may also be removed during this operation.

Having the human immunodeficiency virus can affect treatment of anal cancer


Cancer therapy can further damage the already weakened immune systems of patients who have the human immunodeficiency virus (HIV). For this reason, patients who have anal cancer and HIV are usually treated with lower doses of anticancer drugs and radiation than patients who do not have HIV.

New types of treatment are being tested in clinical trials


This section describes treatments that are being studied in clinical trials. It may not mention every new treatment being studied. Information about clinical trials is available from the NCI Web site.

Radiosensitizers

Radiosensitizers are drugs that make tumor cells more sensitive to radiation therapy. Combining radiation therapy with radiosensitizers may kill more tumor cells.

Patients may want to think about taking part in a clinical trial


For some patients, taking part in a clinical trial may be the best treatment choice. Clinical trials are part of the cancer research process. Clinical trials are done to find out if new cancer treatments are safe and effective or better than the standard treatment.

Many of today's standard treatments for cancer are based on earlier clinical trials. Patients who take part in a clinical trial may receive the standard treatment or be among the first to receive a new treatment.

Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even when clinical trials do not lead to effective new treatments, they often answer important questions and help move research forward.

Patients can enter clinical trials before, during, or after starting their cancer treatment


Some clinical trials only include patients who have not yet received treatment. Other trials test treatments for patients whose cancer has not gotten better. There are also clinical trials that test new ways to stop cancer from recurring (coming back) or reduce the side effects of cancer treatment.

Follow-up tests may be needed


Some of the tests that were done to diagnose the cancer or to find out the stage of the cancer may be repeated. Some tests will be repeated in order to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests. This is sometimes called re-staging.

Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back). These tests are sometimes called follow-up tests or check-ups.

Treatment Options for Anal Cancer by Stage


For some types or stages of cancer, there may not be any trials listed. Check with your doctor for clinical trials that are not listed here but may be right for you.

Stage 0 (Carcinoma in Situ)


Treatment of stage 0 is usually local resection.

Stage I Anal Cancer


Treatment of stage I anal cancer may include the following:

  • Local resection.
  • External-beam radiation therapy with or without chemotherapy. If cancer remains after treatment, additional chemotherapy and radiation therapy may be given to avoid the need for a permanent colostomy.
  • Internal radiation therapy.
  • Abdominoperineal resection, if cancer remains or comes back after treatment with radiation therapy and chemotherapy.
  • Internal radiation therapy for cancer that remains after treatment with external-beam radiation therapy.
Patients who have had treatment that saves the sphincter muscles may receive follow-up exams every 3 months for the first 2 years, including rectal exams with endoscopy and biopsy, as needed.

Stage II Anal Cancer


Treatment of stage II anal cancer may include the following:

  • Local resection.
  • External-beam radiation therapy with chemotherapy. If cancer remains after treatment, additional chemotherapy and radiation therapy may be given to avoid the need for a permanent colostomy.
  • Internal radiation therapy.
  • Abdominoperineal resection, if cancer remains or comes back after treatment with radiation therapy and chemotherapy.
  • A clinical trial of new treatment options.
Patients who have had treatment that saves the sphincter muscles may receive follow-up exams every 3 months for the first 2 years, including rectal exams with endoscopy and biopsy, as needed.

Stage IIIA Anal Cancer


Treatment of stage IIIA anal cancer may include the following:

  • External-beam radiation therapy with chemotherapy. If cancer remains after treatment, additional chemotherapy and radiation therapy may be given to avoid the need for a permanent colostomy.
  • Internal radiation therapy.
  • Abdominoperineal resection, if cancer remains or comes back after treatment with chemotherapy and radiation therapy.
  • A clinical trial of new treatment options.

Stage IIIB Anal Cancer


Treatment of stage IIIB anal cancer may include the following:

  • External-beam radiation therapy with chemotherapy.
  • Local resection or abdominoperineal resection, if cancer remains or comes back after treatment with chemotherapy and radiation therapy. Lymph nodes may also be removed.
  • A clinical trial of new treatment options.

Stage IV Anal Cancer


Treatment of stage IV anal cancer may include the following:

  • Surgery as palliative therapy to relieve symptoms and improve the quality of life.
  • Radiation therapy as palliative therapy.
  • Chemotherapy with radiation therapy as palliative therapy.
  • A clinical trial of new treatment options.

Recurrent Anal Cancer


Recurrent anal cancer is cancer that has recurred (come back) after it has been treated. The cancer may come back in the anus or in other parts of the body.

Treatment Options for Recurrent Anal Cancer


Treatment of recurrent anal cancer may include the following:

  • Radiation therapy and chemotherapy, for recurrence after surgery.
  • Surgery, for recurrence after radiation therapy and/or chemotherapy.
  • A clinical trial of radiation therapy with chemotherapy and/or radiosensitizers.

Side effects of Treatment for Anal Cancer


  • Diarrhea
  • Constipation
  • Soreness and blistering around the target area (anus)
  • A higher susceptibility to infections during treatment
  • Low white blood cell count (which raises infection risk)
  • Fatigue
  • Loss of appetite
  • Nausea or vomiting
  • Mouth ulcers
  • Sore mouth
  • Loss of hair
  • Narrowing and dryness of the vagina
  • Anemia (low red blood cell count)
  • Low platelet count which raises risk of bruising or bleeding
  • Dry skin
  • Rashes
  • Muscle and nerve problems
  • Excessive coughing, sometimes breathing difficulties
  • Fertility problems

Prevention for Anal Cancer


There is no sure way to prevent anal cancer. In order to reduce your risk of anal cancer:

  • Reduce your chances of being infected with HPV
  • Use condoms when having sex
  • Limit the numbers of sexual partners
  • Abstain from anal intercourse
  • Quit smoking
Experts believe the HPV vaccine will reduce the number of anal cancer cases - however, there are no studies yet to confirm this (2009).