Anal Cancer

August 18, 2024

3 min read

Anal cancer or carcinoma of the anal canal is an uncommon malignancy that develops in the anus tissues of the lining of the anal canal.

Types of Anal Cancer

The types of anal cancers include:

Squamous cell carcinoma: The tumor begins in the squamous cells lining the anal margin and the anal canal.
Adenocarcinoma: Some cancers start in the cells lining the upper part of the anus near the rectum, while others begin in the glands under the anal mucosa.

Symptoms of Anal Cancer

Some common symptoms of anal cancer include:

Bleeding from the rectum or anus
Blood in stool
Itching or discharge from the anus
Pain in the anus
A lump or mass that resembles hemorrhoids
A change in the frequency and consistency of the bowel movements

Causes of Anal Cancer

Anal cancer is caused when the cancer cells in the anus grow uncontrollably, forming masses or tumors. The cancer cells can sometimes spread to other body parts, causing metastatic cancer.

The risk factors include:

An HPV (human papillomavirus) infection passed through sexual contact
An age of 55 years and older
Multiple sex partners
Sexually transmitted disease
Having anal sex
Smoking cigarettes
A history of HPV-related cancers like cervical cancer
A weakened immune system due to chemotherapy or an organ transplant
Chronic inflammatory areas in the anus, anal fistulas, or having opened a wound in the anus
Having previous pelvic radiation therapy for bladder, rectal, prostrate, or cervical cancer

Diagnosis of Anal Cancer

Your medical provider will consider your medical and family history and perform a physical examination. They may order tests that include:

A digital rectal exam (DRE): The rectum is examined to look for abnormalities like a lump or growth.
Anoscopy: The anal canal is examined with a small lighted scope called anoscope.
Proctoscopy: The inside of the anus and rectum is examined by a thin tubular instrument with light and lens called a proctoscopy.
Endo-anal or endorectal ultrasound, MRI, PET scan, or other imaging tests: They help determine the location of the cancer.
Biopsy: A tissue sample is collected and checked under the microscope to make an accurate diagnosis.

Stages of Anal Cancer

There are five stages of anal cancer.

Stage 0 ( Carcinoma-in-situ)

The abnormal cell found in the mucosa of the anus that can progress to anal cancer.

Stage I

Anal cancer is present with a tumor of 2 cm or less.

Stage II

It includes:

Stage IIA: The cancerous tumor is between 2 and 5 cm, and,
Stage IIB: The tumor is of 5cms or larger size.

Stage III

It includes:

Stage IIIA: The tumor is 5 cm or smaller. It has spread to the lymph nodes near the groins or anus.
Stage IIIB: The tumor is of any size and has spread to nearby organs like the bladder, urethra, and vagina but not the lymph nodes.
Stage IIIC: The cancer has affected nearby organs and the lymph nodes in the anus or groin.

Stage IV

The cancer has spread far from the anus to other organs like the lungs or liver.

Treatment of Anal Cancer

The treatment of anal cancer is based on the tumor type and size, and may include:

Radiation therapy

Anal cancer is treated with external beam radiation therapy (EBRT) that includes:

Intensity-modulated radiation therapy (IMRT): It emits multiple energy beams to a tumor.
Stereotactic body radiation therapy (SBRT): It targets small tumors without damaging the healthy tissues.
Three-dimensional conformal radiation therapy (3D-CRT): It generates a 3-D picture of the cancer.

Chemotherapy

They are strong medicines used to kill the cancer cells.

Surgery

While small, early-stage tumors can be removed surgically without further treatment, advanced anal cancers may require laparoscopic abdominal perineal resection to remove the rectum, anus, and colon. A permanent colostomy is also done to collect bowel movements in a bag attached outside of the body.