Anus is the organ present in the extreme end of large intestine and is located just below the rectum. Anus is responsible for eliminating stools from the body. Two muscles known as sphincter muscles are involved in the opening and closing of anus while stool is passed out. The area of the anus will develop inflammation and cause bleeding and itching with pain. The outcome of anal cancer depends on its staging and location and size of the tumor. Anal cancer can be treated and cured if detected in early stages. In advanced stage, cancer would recur even after effective treatments and the survival rate is less.
Anal cancer develops when cancer causing cells grow in the tissues of the anus. People who are sexually active with multiple sex partners and those who have frequent HPV infection develop anal cancer.
Risk Factors :
Being older (above 50 years), having many sex partners, getting frequent HPV infections, having anal sex, having fistulas on the anus and smoking can increase the risk of getting anal cancer.
Some of the signs of anal cancer are bloody discharge from the anus/rectum, itching over the anal region, pain, formation of lesions or lump in the anus and sudden change in bowel movements. Getting genital warts is an indication of anal cancer. The rate of survival is more if anal cancer is detected in early stages than in the final stage. Single men have high risk of getting anal cancer than married men.
After knowing the symptoms, your doctor will collect complete medical history and do physical exam. She would find out if any lumps are present in the anal region or if there is any abnormal growth inside. The doctor would examine the rectum and anus by anoscopy and proctoscopy. In this procedure, biopsy of the tissue sample is done and tested in the lab.
Once presence of anal cancer is confirmed, the doctor will order for series of test to find out how far the cancer cells have invaded in the body. Complete CT scan of the body is done exploring areas of pelvic region and abdomen thoroughly. The therapist will look for any abnormality in the tissues to detect anal cancer. If required, MRI scan or PET scan will be done.
The chance of complete recovery depends on the location, size of the tumor and how far it has spread. The doctor will choose the treatment method based on the staging of anal cancer.
How cancer spreads?
Cancer (of any type) can spread through 3 ways in the body.
- One is by way of tissues thus invading the nearby tissues.
- Second method is through lymph nodes that are present throughout the body. Once they gain entry into the lymph nodes the cancer cells can reach anywhere in the body.
- Third method that cancer cells spread in the body is through blood. It enters into the blood vessels to reach distant parts.
Metastasis is the process by which cancer cells spread to any part of the body from the place of its origin. Cancer cells travel through lymph system or blood and forms a tumor causing more trouble and interfering with the normal function of the organ in which it has reached.
- Stage 0 is the initial stage of anal cancer. Here the abnormal cancer cells would invade the tissues nearby. No symptoms are seen at this stage.
- Stage 1 is the session in which the cancer has grown into a tumor mass invading more and more tissues of anal wall and rectum.
- Stage 2 the tumor size becomes bigger and bigger (2-3 cm). Now the cancer cells have crossed the anal wall and gains entry into the other tissues nearby.
- Stage 3: At this stage the cancer cells would have entered one or two lymph nodes of the rectum. Sometimes it would form a tumor in the nearby organs like uterus, vagina and bladder.
- Stage 4: Now the cancerous tumor would grow larger gaining entry in the nearby lymph nodes like groin or pelvic floor through which it travels to distant areas.
- Stage 5: It is the final stage in which cancer has spread far into the body cells attacking various parts of the body.
Chemotherapy, radiation and surgery are the 3 major methods of treating anal cancer. The doctor decides the course of treatment after considering several factors like age of the patient, health condition, and intensity of cancer, location and size of cancer. He would also take into account the stage of cancer before starting the treatment.
- Chemotherapy :
Medications are given to arrest the growth of cancer cells. It is given as shots through vein or as oral pills. The drugs would travel into the blood to reach the cancer causing cells and destroy them.
- Radiation Therapy :
This method uses high powered beam of radiation waves to kill cancerous cells. It can be either external (a machine kept outside would send radiation into the cancer cells) or internal (radioactive catheters or needles are implanted into the body). Often chemo and radiation therapy are combined to get the best result.
- Surgery :
It is the option chosen if cancer has advanced or if the tumor size is large. Local resection will be done to remove the tumor along with some healthy tissues nearby. This method is used to remove cancer from lower part of the anus. If the cancer has metastasized, abdominoperineal resection will be done. Part of rectum, anus and colon will be removed during surgery.
In many cases the anus and rectal area will be removed completely and a bag is kept outside the body on which the waste products (stool) are collected. Prognosis depends on the staging and health condition of the patient. It is difficult to give treatment if the patient with anal cancer is found to have HPV infection.