Anal cancer – causes, risk groups, prognosis. The most embarrassing cancer

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Anal cancer is a disease that has been affecting more and more people in recent years. This is due to the growing number of people infected with HIV and HPV. In Poland, about 300 people are diagnosed with the disease every year. In others, it remains undiagnosed because anal cancer often has minor and non-specific symptoms. We advise on what to look for in order to diagnose the disease at an early stage.

What is anal cancer?

Anal cancer is not a straightforward concept, as there are several types of the condition distinguished by location. We can therefore deal with:

1. anorectal tumor;
2. cancer of the anal canal (the anal canal is the end section of the gastrointestinal tract) – it is mainly a squamous cell tumor.

In the case of anal canal cancer, we can also mention the types of cancer that are diagnosed much less frequently, e.g. undifferentiated cancer, poorly differentiated cancer, small cell cancer, adenocarcinoma (rectum). The best prognosis is in patients with anal edge cancer.

Anal cancer is a malignant neoplastic tumor which increases in size as the disease progresses and may consequently infiltrate adjacent lymphatic and blood vessels and surrounding organs. Anal cancer may lead to metastasis within the lymph nodes (inguinal and perianal nodes) because cancerous cells spread from the tumor through the lymph vessels. However, metastases to other distant organs appear rarely, it is about 15% of cases where secondary tumor foci are located in the lungs or liver.

Anal cancer causes

There are many factors that influence the formation of rectal cancer. The risk is especially increased in people who smoke cigarettes, which are the cause of many other cancers, e.g. lung, kidney, pancreas. In summary, anal cancer is more likely to occur in the case of:

1. having unprotected anal sex,
2. cervical dysplasia or cancer,
3. HPV infection (human papilloma) 6, 16, 18,
4. warts on the genitals,
5. Bowen’s disease (it is a type of pre-invasive cancer – in situ, which is located in the epithelium and infiltrates deeper tissue structures),
6. white keratosis,
7. chronic immunosuppression (transplant patients, long-term therapy with steroids),
8. haemorrhoids,
9. anal fissures,
10. anal fistulas,
11. genetic mutation on chromosomes 3 and 11.

Who is at risk of developing anal cancer

Anal cancer usually affects people aged 50-60, although it is increasingly found in the younger population. People with this type of cancer in their family are most at risk of developing it. But not only. Doctors distinguished groups of special risk and identified factors that increase the likelihood of developing the disease.

1. Cancer of the anus, both of the canal and the edge, most often develops in immunocompromised individuals. HIV-infected and AIDS patients are at particular risk of developing cancer.
2. Another risk factor is engaging in unprotected anal intercourse. Therefore, anal cancer is often found in homosexual men.
3. There was also a link between the disease and the number of sexual partners. This applies to both women and men. The more partners, the greater the risk of anal cancer.
4. It is worth remembering that sexual abstinence is also not healthy, especially for women. Researchers have found that women who have intermittent sex or are sexually abstinent are more likely to develop anal cancer.
5. Everyone who has been diagnosed with a sexually transmitted disease is at risk.
6. The risk group also includes patients who use immunosuppression and those with chronic inflammatory diseases, such as anal fissure or fistula, as well as chronic apocrine inflammation.
7. In women, however, risk factors include cervical cancer, tubal ligation and the use of oral contraceptives.
8. It is also worth remembering that anal cancer is more common in women who smoke. An association between anal cancer and smoking has not been found in men.

Anal cancer symptoms

The disease may be asymptomatic for many years. Only at an advanced stage of development, symptoms such as:

1. blood in the stool
2. spontaneous rectal bleeding or bleeding while passing stools
3. diarrhea or constipation
4. feeling of incomplete bowel movements,
5. abdominal or perineal pain
6. intestinal colic that causes the need to have a bowel movement
7. pain, burning and itching around the anus,
8. foreign body feeling
9. painful pressure on the stool
10. fecal and gas incontinence,
11. serous-bloody spills,
12. the inguinal lymph nodes are also often enlarged.

These symptoms do not always indicate anal cancer. Blood in the stool or the feeling of incomplete bowel movements may also indicate the presence of hemorrhoids, popularly known as hemorrhoids. It is worth remembering, however, that anal cancer and hemorrhoids may coexist, so when additional symptoms appear, e.g. a change in the nature of bowel movements (once diarrhea, once constipation), contact a doctor as soon as possible.

(NO) Difficult diagnosis of anal cancer

Anal cancer diagnosis seems simple. The doctor collects an interview, conducts a physical examination, and also performs per rectal examination (rectal examination with a finger), rectoscopy, transrectal ultrasound, computed tomography and histopathological examination. Although physicians are familiar with the diagnostic scheme, errors often occur. Why? There are many reasons for this. Sometimes we have a single, small lesion in the anal canal that, while dangerous, does not seem so. And we, as well as the doctor, often underestimate it. It may also happen that we report worrying symptoms to the doctor, and he decides not to have a biopsy because he thinks the symptoms do not suggest cancer. Or it treats a rectal lesion without histopathological verification. Most often, however, the fault lies with us, the patients. We often underestimate symptoms, chronic diarrhea, constipation or blood in the stool. We do not come for tests and we have never had a rectal examination done. As a result, we come to the doctor when it is very late, and sometimes too late for a cure.

Therefore, it is worth remembering a few rules:

1. If you are at risk of anal cancer, report it to your doctor and perform a rectal examination from time to time (depending on the indications). This examination can be performed by your family doctor!
2. Rectal bleeding, a change in bowel habits, or an unusual change in the canal or area around the anus should worry you. This requires an urgent medical consultation.
3. Do not heal yourself with home remedies. See a doctor immediately. It is best to ask a proctologist who deals with diseases of the anus for consultation.

Briefly, the tests carried out in the diagnosis of anal cancer include:

1. fine needle biopsy of inguinal lymph nodes;
2. per rectum examination;
3. histopathological examination using a sample taken;
4. x-ray examination;
5. computed tomography of the chest;
6. transrectal ultrasound examination (using a probe inserted into the anus; allows to assess how deeply the tumor infiltrates the tissue area);
7. colon endoscopy;
8. computed tomography or magnetic resonance imaging of the abdominal cavity and the small pelvis (determines the size of the tumor, presence or absence of metastases, lymph node involvement, extent of infiltration);
9. gynecological examination in women.

Anal cancer therapy

Anal cancer treatments include:

1. local excision of the anus,
2. anterior resection with sphincters,
3. abdominocerebral excision with the creation of an artificial anus, i.e. a colostomy (stoma created on the large intestine).

Which method of treatment will be used depends, among others, on on the size of the tumor, the distance of the tumor from the edge of the anus and the depth of invasion. In patients with advanced stages of cancer development, radiation is usually given before surgery. The goal is to destroy cancer micrometastases and microfocus in the lymph nodes. After surgery, adjuvant chemotherapy is administered.

Currently, the basic therapy in the fight against anal cancer is the simultaneous use of radio- and chemotherapy using 5-fluorouracil and mitomycin, while local tumor excision is performed when the tumor is well-differentiated, its size does not exceed two centimeters and has no metastases. After the end of the treatment with radiochemotherapy (after about 6-8 weeks), the patient is checked-in to determine the effectiveness of the treatment. If the doctor determines that the treatment has brought remission, the patient should undergo regular checkups for 5 years, including: anoscopy, rectal examination, palpation of lymph nodes and inguinal nodes. If the rectal cancer is advanced, a control examination should be performed using a chest X-ray and a CT scan of the smaller pelvis.

What if the patient cannot be cured after initial radiochemotherapy?

1. it may be necessary to repeat radiochemotherapy or abdomino-perineal resection (if the biopsy shows the presence of cancer cells),
2. patients undergo repeated abdominoperineal resection and radiochemotherapy also in a situation where, despite the remission of the disease, a recurrence occurs after some time (local recurrence, anal tumor),
3. removal of lymph nodes or repeated radiotherapy or chemotherapy is recommended when relapse after RCHT treatment in the lymph nodes,
4. the following treatment is recommended: doxorubicin, semustine, carboplatin, chemotherapeutic drugs and cisplatin with 5-fluorouracil, when the relapse of the disease affects a site other than the anus, e.g. liver metastases.

Anal cancer – complications of radio- and chemotherapy treatment

Treatment of anal cancer with radio- or chemotherapy can cause complications, which can be divided into two groups:

1. early complications, which include:

1. pain,
2. diarrhea
3. erythema,
4. peeling of the epidermis,
5. mucositis,
6. myelosuppressed;

2. late complications, which include:

1. anal stricture,
2. stool holding problems
3. anal ulcer
4. anal fissure,
5. necrotic lesions.

Anal cancer and prognosis

The TNM classification is helpful in determining the prognosis of patients with anal cancer, which assesses:

1. primary tumor site (T),
2. adjacent lymph nodes (N),
3. distant metastases (M).

The chances of a patient’s recovery depend primarily on the size of the original tumor and whether the lymph nodes have metastasized. If a patient has a T1 or T2 tumor, which is up to 5 cm in size, there is a chance of 5-year survival in 80-90%. On the other hand, in advanced T4 neoplasm (tumor infiltration into nearby organs, such as the bladder or vagina), the five-year chance of survival is less than 50%. When the cancer affects the lymph nodes, the patient automatically has a lower chance and a much worse prognosis, then the chance of 5-year survival is only 25-40%.