Anal cancer

What is anal cancer?

In people with anal cancer, a malignant tumor forms in the anal canal. This anal canal corresponds to a section a few centimeters long that connects the intestine to the anus. Synonyms for anal cancer are the terms anal carcinoma or anal canal carcinoma.

Sometimes the cancer also forms at the point where the anal canal joins the skin of the anus. Doctors call this cancer anal cancer. Although anal cancer falls into the group of colon tumors, it has some different characteristics than rectal or colon cancer.

Anal cancer and bowel cancer – the differences

There are some differences between anal and colon cancer. First of all, the two types of cancer usually originate from different cell types. A pathologist can easily recognize these differences under the microscope.

Anal cancer cells usually have the characteristics of a so-called squamous cell carcinoma (a type of skin cancer). The cancer usually originates from the skin or mucous membrane cells. The majority of people with anal cancer have squamous cell carcinoma. From a medical point of view, anal cancer is also a malignant skin tumor. Colon cancer, on the other hand, originates mainly in the glandular tissue. It therefore belongs to the group of adenocarcinomas.

Anal cancer – frequency and age

Compared to other cancers such as breast, prostate, bowel or lung cancer, anal cancer is a rare type of cancer. Only an estimated 200 people in Switzerland contract the disease each year. Anal cancer accounts for less than one percent of all cancers. Anal cancer affects women significantly more often than men: 70 percent compared to 30 percent. Around half of all those affected are between 50 and 69 years old at the time of diagnosis. Around 40 percent are aged 70 and over.

Anal cancer: often caused by HP viruses

The most important cause of anal cancer is viruses, which is why it is considered a chronic viral infection. Human papillomaviruses (HPV) are responsible for this cancer. In most people, anal cancer can be traced back to infection with HP viruses. Infection usually occurs during sexual intercourse. The HPV infection is a sexually transmitted disease. Sexually Transmitted Diseases (STD).

There are different types of human papillomaviruses, which vary in aggressiveness and danger:

• High-risk types: These include HPV 16 and HPV 18, for example. Both also play a decisive role in cervical cancer or penile cancer.
• Low-risk types: This group includes HPV 6 or HPV 11, for example, which primarily cause genital warts that are benign but extremely unpleasant. They hardly increase the risk of cancer.

In addition to such chronic infections in the anal area, other risk factors also play a role. Examples are:

• Weakened immune system, for example in the case of an HIV infection or after an organ transplant
• Mechanical factors (e.g. pressure, friction) can strain the anal region and damage it over time. As a result, anal fistulas or anal fissures can form. Fistulas are unnatural passages in the tissue that do not actually belong there. These tube-like connections link tissues and organs together. Fissures, on the other hand, are small tears in the skin or mucous membrane. Typically, they cause considerable pain.

In contrast to bowel cancer, neither lifestyle nor existing bowel diseases (e.g. Crohn’s disease, ulcerative colitis) appear to be involved in anal cancer. An unhealthy diet with lots of fat and little fiber, as well as intestinal polyps, are considered risk factors for colorectal cancer.

Symptoms: Anal cancer often without clear signs

Anal cancer is not easy to recognize because the symptoms are rather unspecific and can also occur with other (far more harmless) diseases. These include, for example, hemorrhoids, from which many people suffer. An anal fissure can also be accompanied by similar symptoms.

The following signs may indicate anal cancer:

• Stool: blood deposits or blood admixtures – this is always a case for a visit to the doctor
• Pain during bowel movements
• Itching or pain in the anal area
• Mucus secretions from the anus
• Skin changes, hardening
• Stool irregularities
• Specially shaped chair: notches or thin “pencil chair”
• Defecation cannot be adequately controlled – fecal incontinence is possible. Stool is released involuntarily and unintentionally.
• Swollen lymph nodes in the groin region

These symptoms are not necessarily caused by anal cancer. Do not hesitate to consult your family doctor promptly if you notice such symptoms. She or he can find out what is actually behind it.

Generally speaking, the earlier doctors discover the cancer, the better it can be treated and the higher the chances of recovery.

Diagnosis

Diagnostics always begin with a discussion with your doctor about your medical history (anamnesis). Your answers to the following (and other) questions will provide him with initial clues as to what could be the cause of the complaints:

• What exactly are your symptoms? Z. E.g. blood in the stool, problems with bowel movements
• When did the symptoms first occur and how intense are they?
• Do you have any known diseases in the anal area, for example anal fissures or anal fistulas?
• Are there any known infections?
• Do you suffer from other underlying diseases? If yes: Which ones?

If anal cancer is suspected, further examinations will follow. These include:

• Digital rectal examination (DRU, palpation examination): We palpate the anal canal with a finger. Abnormalities can often already be detected in this way.
• Endoscopy of the rectum (rectoscopy): We examine the rectum and usually also the last few centimeters of the anus.
• Colonoscopy (colonoscopy): We insert a flexible instrument equipped with a camera into the bowel. It provides images from inside the intestine. Changes can be easily detected by colonoscopy.
• Removal of tissue (biopsy): If anal cancer is suspected, a biopsy is performed. We remove tissue from the suspicious area. The cells can usually be obtained during the colonoscopy. A pathologist then analyzes the removed tissue under a microscope in the laboratory. Benign and malignant cells can be easily distinguished. The diagnosis of anal cancer can be made with certainty on the basis of the tissue sample.

Determining the stage of anal cancer

Once anal cancer has been diagnosed, we determine the spread and stage of the tumor. “Staging” is the technical term for this. It is extremely important for the treatment whether the cancer is still localized or has already spread to the lymph nodes or other organs. The so-called TNM classification is used internationally:

• T = tumor: There are stages T1 to T4; the larger the tumor, the larger the number after the T.
• N = lymph node (node): Are cancer cells detectable in the lymph nodes (lymph node metastases)? If so, the cancer has already set off on its “journey”.
• M = Metastases: Has the cancer already spread to other organs or formed metastases (distant metastases)?

The following examinations help us to classify the stages:

• Ultrasound (sonography): We examine the pelvis from the outside using an ultrasound probe. There is also an ultrasound examination of the bowel (from the inside, endosonography).
• Magnetic resonance imaging (MRI or magnetic resonance imaging): This method works with strong magnetic fields and produces sectional images in different planes. The body is picked up in “slices”. An MRI makes soft structures (tissue, organs) particularly easy to visualize. Metastases can also be detected in this way.
• Computed tomography (CT): This imaging examination uses X-rays. Radiologists generate high-resolution cross-sectional images here – as with MRI.
• PET-CTWe use computer tomography in conjunction with metabolic markers, which can be used to visualize specific cancer foci.

Anal cancer: prevention, early detection, prognosis

Human papillomaviruses are often at work in anal cancer. And you can become infected with these during sex. However, there is no one hundred percent protection against infection. You can prevent this to a certain extent by taking the following measures:

• HPV vaccination: This provides effective protection against the most dangerous HPV variants and can therefore reduce the risk of anal cancer. The HPV vaccination also reduces the risk of cervical cancer, penile cancer and malignant tumors in the mouth and throat. The vaccination is recommended for girls, young women, boys and young men in Switzerland.
• Use condoms during sexual intercourse. They not only protect against unwanted pregnancy, but also against many pathogens and sexually transmitted diseases.
• Pay attention to careful hygiene in the intimate area. Do not forget the anal region.
• Be careful with sexual practices that can injure and damage the anal region. Otherwise, use lubricant to protect the sensitive mucous membrane.

There are also a number of examinations for the early detection of cancer. The aim is to find a possible cancer as early as possible. However, these examinations cannot prevent cancer. In Switzerland, citizens over the age of 50 can take part in colorectal cancer screening. This program includes a blood in stool test every two years or a colonoscopy every ten years. The health insurance companies cover the costs. Bowel cancer screening can also be used to detect anal cancer. Ask your doctor or health insurance provider which examination is suitable for you and from what age you can take advantage of it. At the USZ we offer a special consultation for the early detection of anal cancer (HPV consultation).

Progression and prognosis of anal cancer

The course of anal cancer is positive in many cases and the prognosis is favorable. The earlier we diagnose anal cancer, the better the chances of recovery. Conversely, if the tumor is already more advanced, the prognosis worsens. If the malignant tumor is still localized and has not spread, anal cancer can be cured in many cases with the right treatment. We usually rely on surgery, chemotherapy and radiation.

Rehabilitation and aftercare for anal cancer

Regular follow-up care is always important after cancer treatment. We try to alleviate the consequences of the cancer and its treatment and to recognize a relapse (recurrence) in good time. In the beginning, more frequent checks every three months are advisable. After that, the time intervals become longer and longer.

Rehabilitation (or rehab for short) can also be helpful for those affected by anal cancer. This is especially true after an operation, chemotherapy or radiotherapy, which can leave some physical and mental traces. Some suffer from faecal incontinence, have an artificial anus or are struggling with the consequences of radiotherapy.

In rehab, you will learn how to cope better with the cancer and possible limitations in everyday life and at work. The aim is to restore quality of life as far as possible.

Anal cancer: treatment usually depends on the stage

There are various strategies for treating anal cancer. We usually combine several therapies in order to increase their effectiveness. Which treatments you choose depends on the stage of the cancer, but also on your age, state of health and personal wishes.