How does a tumor develop?
The anal canal is lined with flat epithelium, similar to the epithelium of the cervix, and passes into the mucous membrane of the rectum. The human papillomavirus of high oncogenic risk can integrate into the cells of this epithelium and cause their restructuring. First, dysplasia occurs - precancerous changes that are not felt at all. Over the years, some of them develop into invasive cancer, growing into the submucosal layer and sphincter muscle. The tumor spreads to surrounding tissues and lymph nodes - inguinal, pelvic, which is taken into account when planning treatment.
- Squamous cell carcinoma is the main variant
- Precancerous stage - anal intraepithelial neoplasia
- Tumors of the anal canal proper
- Tumors of the edge of the anus
- Spread to inguinal and pelvic lymph nodes
Risk factors
The main factor is persistent infection with the human papillomavirus of high oncogenic risk. Additionally, the risk is increased by conditions in which the immune system cannot cope with the virus: HIV infection, taking immunosuppressive drugs after transplantation, chronic diseases. Smoking plays a significant role. The risk is increased in women who have previously had cervical dysplasia or cancer, since we are talking about the same virus. Chronic anal fistulas and prolonged inflammatory processes are also considered predisposing factors.
- Persistent high-risk HPV infection
- HIV infection and other immunodeficiencies
- Taking immunosuppressive drugs
- Smoking
- History of cervical dysplasia or cancer
- Large number of sexual partners, anal intercourse
- Chronic fistulas and inflammation in the anal area
Symptoms
Early manifestations are nonspecific, and this is the main danger. Most often, the first thing to appear is blood discharge during bowel movements - this is why the disease is mistaken for hemorrhoids. Then there is pain and a sensation of a foreign body, itching, discharge, sometimes the patient himself feels a dense node or a non-healing ulcer. A warning sign is a change in the functioning of the sphincter: leakage, gas incontinence, false urges. When the lymph nodes are affected, dense, painless formations appear in the groin. Weight loss and weakness are characteristic of the later stages.
- Blood during bowel movements
- Pain and feeling of a foreign body in the anus
- Itching and discharge
- Palpable lump or ulcer
- Incontinence of gas and feces
- Change in stool shape, false urges
- Dense lymph nodes in the groin
Diagnostics
The examination begins with examination and digital examination of the rectum, then anoscopy is performed. Any suspicious formation, ulcer or lump must be biopsied - only histological examination confirms the diagnosis. To assess the spread of the tumor and the condition of the lymph nodes, an MRI of the pelvis is used, and, if necessary, a CT scan of the chest and abdomen. Be sure to examine the inguinal lymph nodes, and if they are enlarged, a puncture is taken. Women are recommended to be examined by a gynecologist with cervical cytology, and all patients are offered HIV testing.
- Digital examination of the rectum
- Anoscopy and sigmoidoscopy
- Biopsy with histological examination
- MRI of the pelvic organs with contrast
- CT scan of the chest and abdomen
- Ultrasound and puncture of inguinal lymph nodes
- High-risk HPV and HIV test
- Examination by a gynecologist and cytology of the cervix in women
Treatment and prevention
The main method of treatment is a combination of radiation and chemotherapy. This approach allows most patients to completely remove the tumor while preserving the rectum and sphincter, that is, avoiding a permanent stoma. Surgery to remove the rectum is reserved for cases where chemoradiotherapy has failed or the disease has returned. Small tumors on the edge of the anus are sometimes removed locally. The best prevention is vaccination against HPV in adolescence, quitting smoking and timely examination in case of bleeding.
- Chemoradiation therapy as the main method
- Local excision for small tumors of the anal verge
- Surgery if treatment fails
- Treatment of affected lymph nodes
- Observation with examination and MRI according to the oncologist’s schedule
- Vaccination against HPV
- Quitting smoking
- Regular screening for HIV and immunosuppression
