The anal canal is the end of the digestive tract, connected to the rectum on the upper part and the anus on the lower part. During each bowel movement, the stool leaves the rectum and passes through the anal canal before being discharged from the body. Anal cancer mostly occurs on the anal canal or the skin of the anal margin. Anal canal cancer grows on the dentate line, and perianal cancer grows below the dentate line. If the precancerous lesions around the anus are not treated, they will become cancerous over time. Since the treatment of precancerous lesions and anal cancer is completely different, early treatment is very important.
Data and facts
About two-thirds of anal cancers occur in women.
Anal cancer accounts for less than 2% of colorectal tumors.
The common age of onset of anal cancer is 55-64 years.
One out of every 500 people will suffer from anal cancer, and one out of 22 people will suffer from colorectal cancer, but the incidence of anal cancer is increasing year by year.
Anal cancer rarely has distant metastasis, but it is difficult to treat patients with metastases. The common metastatic sites of anal cancer are liver and lung.
High risk factors
The most common risk factor for anal cancer is human papilloma virus infection. Human papilloma virus is a virus transmitted by sexual contact, which can cause condyloma acuminata around the genitals and anus of an infected person. But not all anal cancers have human papilloma virus infection. Other high-level factors include:
Age>55 years old.
Sexually transmitted diseases.
Multiple sexual partners.
History of human papillomavirus-related tumors, especially cervical cancer.
Reduced immunity caused by HIV infection, chemotherapy or organ transplantation.
Long-term chronic irritation injuries such as anal fistulas or open wounds in the anal area.
Rectal cancer, prostate cancer, bladder cancer or cervical cancer received pelvic radiotherapy.
Although cancer is rarely completely preventable, avoiding high-risk factors and regular check-ups are still very important. Using condoms can only reduce the risk of human papillomavirus infection, but it cannot avoid infection. Human papillomavirus vaccine (for people aged 9-26) can not only reduce the risk of viral infection, but also reduce the risk of anal cancer. Patients at high risk of anal cancer should consult your doctor and undergo regular screening. Anal cytology screening and anoscopy can detect whether there are abnormal cell or tissue proliferation. Early detection and treatment of precancerous lesions can prevent the occurrence of anal cancer.
About 20% of patients with anal cancer have no special symptoms. The following symptoms are similar to common symptoms of diseases such as internal hemorrhoids and anal fissures, which are easy to be misdiagnosed clinically. But if you have any similar symptoms, you should consult a doctor as soon as possible:
Blood in the stool.
Pain in the anal area.
Anal mass prolapsed.
Persistent anal itching.
Changes in bowel habits (such as increased or decreased bowel movements).
Stool shape becomes thinner.
Mucus or pus is drained from the anus.
Swollen lymph nodes in the anus or groin area.
Most anal cancers are relatively early when they are discovered, because tumors in this area are easier to detect by doctors. Patients with any of the above symptoms can generally be diagnosed after anal examination. Some patients with anal cancer were accidentally discovered during routine physical examinations due to the need for digital anal examination to examine the rectum, prostate or other pelvic organs, and some patients with anal cancer were discovered during colonoscopy screening.
Digital rectal examination is the doctor inserting gloved and lubricated fingers into the anus and rectum to check for bumps or other abnormalities.
An anoscope is a small and portable endoscope used to check the anus for abnormalities.
Biopsy is to remove the diseased tissue from the lesion and place it under a microscope to check whether it is cancer. It is the most important part of cancer diagnosis.
Anal ultrasound, MRI or other imaging tests are performed after the diagnosis of anal cancer to determine the extent of tumor invasion and whether there is metastasis.
The cure rate of early anal cancer is relatively high, and the main treatment methods include the following three:
Surgery: including local resection or transabdominal resection.
Radiotherapy: Use high-energy rays to kill cancer cells.
Chemotherapy: The use of drugs to kill cancer cells.
The combination of radiotherapy and chemotherapy is the "gold standard" for most anal cancer treatment. Anal cancer with a small size and an early stage of the tumor can be treated by local resection, which can preserve the function of the anus. But for advanced anal cancer, a wide range of surgical methods are required.
What is an ostomy?
This is also the question of many patients and their families. The so-called colostomy is an artificial opening in the abdominal wall, the end of the colon is pulled out of the opening and sutured to the abdominal wall. Then stick the ostomy bag to the abdominal wall to collect the feces discharged through the stoma.
Because advanced anal cancer requires transabdominal perineum combined rectal resection, which removes the anus and rectum, a permanent colon stoma is required.
Most anal cancers can be cured by combination therapy. Although combined radiotherapy/chemotherapy can increase side effects, it can increase the cure rate. If all treatments can be completed as planned, the 5-year survival rate of patients can reach 70%-90%. Regular follow-up after the operation is also a very important link. Your doctor will evaluate the effect of the treatment and check for signs of recurrence and metastasis, and if necessary, conduct related checks based on the situation.