Anal cancer and anal canal cancer

Contenidos

What is anal cancer ?

Anal cancer is a rare malignant tumor that grows in or around the anus. Most anal cancers grow within the mucous membrane of the anal canal. This is located between the rectum and the anal verge. Other perianal cancers grow in the skin outside the anal verge.

Most anal cancers are classified as squamous cell carcinoma (SCC). There are two types:

Keratinizing SCC or Basaloid SCC: This grows outside the anal canal
Non-keratinizing SCC or cloacogenic SCC – this grows inside the anal canal

An anal adenocarcinoma is a rare form of anal cancer. It grows from glandular cells at the junction of the anal canal and rectum, the transition zone. Other forms of anal cancer include basal cell carcinoma , lymphoma , sarcoma , mucosal melanoma , extramammary Paget’s disease.

Who gets anal squamous cell cancer?

Anal squamous cell cancer occurs in both men and women. It is slightly more common in women than men, but is rare in both sexes, with an annual incidence rate of 1 in every 100,000 people. It usually appears in adults over 45 years of age (80% are over 60 years of age), but it is rarely diagnosed in young adults.

The risk of anal cancer is higher in the following groups of patients:

People with anal intraepithelial neoplasm (AIN): a precursor lesion
Men and women who have receptive anal intercourse
Men and women infected with human immunodeficiency virus ( HIV ) Anal cancer is more common in patients with advanced disease, acquired immunodeficiency syndrome (AIDS), when the incidence is 137 in 100,000.
Men who have had sex with men
Immunocompromised patients, e.g. organ transplant recipients
Intravenous drug users
People with a high number of lifetime sexual partners
Cigarette smokers, who are 4 times more likely than non-smokers to have anal cancer
People who injured the anal mucosa, such as anal fistulas in inflammatory bowel disease or anal trauma
Women, and less often men, with lichen sclerosus
People with a history of genital warts.
Women with a history of cervical cancer, abnormal cervical smears (CIN), vulvar cancer, vulvar intraepithelial carcinoma (VIN), or men with penile cancer or intraepithelial carcinoma (PIN).

In people who have had more than one type of cancer due to human papillomavirus (HPV) infection , anal cancer may occur at the same time, after, or before cancers in other genital sites (cervix, vulva , vagina, and in men, penis).

Patients with anal cancer (eg, adenocarcinoma) who do not have HPV infection are older than HPV-positive patients.

What causes anal cancer?

Almost all anal cancers (90%) are attributable to persistent infection with HPV, the cause of genital warts. Certain strains of HPV are known to be oncogenic (cancer-causing), especially HPV types 16 and 18, and these two infections cause more than 90% of anal cancers. In rare cases, HPV subtyping has detected low-risk strains, such as HPV 6 or multiple HPV strains associated with anal cancer. HPV infection is acquired sexually, but it is not necessary to have had anal sex for HPV to reach the anal canal. HPV is detected with the same frequency in the anus as in the cervix, although anal cancer is not as common as cervical cancer.

In Australia and New Zealand, anal cancer rates are increasing in association with documented increases in HPV infection.

What are the symptoms and signs of anal cancer?

Anal cancer can occur with:

Bleeding from the anus
A growing lump inside or outside the anus
Anal itching or pain
TO mucus or jelly-like discharge from the anus
Constipation, bloating, diarrhea or fecal incontinence (leakage), which may cause incontinence associated dermatitis .

Symptoms are often initially thought to be due to hemorrhoids (piles), polyps, or skin tags.

See images of anal cancer.

How is anal cancer diagnosed?

Anal cancer can be suspected by the appearance of the lesion, which is an irregularity. nodule on the surface of the skin or inside the anal canal and bleeds easily on contact. It can be detected by digital anal examination, anoscopy (use of a special instrument to inspect the anus), proctoscopy/sigmoidoscopy (inspection of the rectum), or colonoscopy (inspection of the entire colon or large intestine).

High-risk patients (for example, those with HIV infection or immunocompromised after organ transplant) may be offered anal cytology smears to detect high-grade squamous intraepithelial lesions, similar to those used in cervical cancer screening. . A swab is inserted into the lower rectum and rolled around the anal canal as it is withdrawn. The swab is processed in the laboratory and examined for abnormal cells. Suspicious smears are followed by high-resolution anoscopy.

Skin or mucosa biopsy is then performed to confirm the diagnosis by histopathology .

Imaging is usually done before treatment to determine the extent of the cancer and whether it has spread to local lymph glands or other parts of the body. Tests may include:

Ultrasound scan
Connecticut scan
MRI scan
chest x-ray
Blood test.

How is anal cancer treated?

Anal cancer is usually treated by a combination of:

Surgical excision of small external lesions
Radiotherapy
Chemotherapy .

Radiation therapy and chemotherapy without surgery preserve the anal sphincter so that the patient can continue to have normal bowel movements with a reduced risk of stool incontinence.

Perineal abdominal resection A colostomy is not usually required, but may be performed if initial treatment is unsuccessful. The procedure involves excision of the anus, rectum and a section of the colon, surgical closure of the rectum and deviation of the colon to open into the abdominal wall.

What is the prognosis after anal cancer treatment?

Cure rates depend on the thickness of the tumor and whether the cancer has spread to other sites at the time of diagnosis. In general, 5-year survival is 60% for men and 70% for women.

Treatment may cause fecal incontinence.

Long-term follow-up can detect secondary spread of cancer ( metastasis ) to local lymph glands or elsewhere. These are difficult to treat. Additional radiation treatment or chemotherapy may be offered.

Can anal cancer be prevented?

The HPV vaccine is expected to reduce the incidence of anal cancer in the future. In Australia, boys and girls are offered the quadrivalent HPV vaccine (Gardisil™), protecting them against HPV 16, 18, 6 and 11. In New Zealand, the 9-voucher vaccine is offered to boys and girls up to the age of 26 years. Vaccination Programs vary in other countries.

Most sexually active men and women will acquire at least one genital HPV subtype, most within the first 5 years of beginning sexual activity. For maximum effectiveness , vaccination should be performed before the start of sexual activity. HPV infection rates can be reduced by using condoms during sex and limiting the number of sexual partners.

“It is essential to address health topics such as anal cancer with seriousness and responsibility. Although it is often associated with risk factors such as human papillomavirus (HPV) infection and other hereditary factors, it is also important to highlight the significance of maintaining good anal health and understanding our own bodies.

While discussing anal cancer prevention and the importance of early detection tests, it is crucial to remember that each person has their own path to health. Some individuals may find comfort and relief in certain medical devices, such as plugged anal, which may be recommended by healthcare professionals in specific situations, such as the treatment of certain anal disorders. However, it is important to emphasize that the use of these devices should be guided and supervised by a specialized medical professional.

Our main goal is to promote awareness about anal cancer, its risk factors, the importance of early detection, and available treatment options. If you have concerns about your anal health or need more information about anal cancer, we recommend that you reach out to a qualified healthcare professional. Your well-being and health are paramount.”