Anal cancer – symptoms , causes, and treatment of cancer of the edge and anal canal

Anal cancer can involve both the margins of the anus and the anal canal. Anal cancers are malignant neoplastic tumors. Symptoms include rectal bleeding, rectal mucus, itching, gas and faecal incontinence. Treatment of anal cancer involves surgery – removal of the tumor, chemotherapy and radiation therapy. Unfortunately, after treatment, there is a high risk of complications. The prognosis of anal cancer depends on the size and location of the tumor.

Anal margin cancer and anal canal cancer – what is it?

At the outset, it should be noted that the concept of anal cancer is not clear-cut. Due to the location, it is possible to distinguish cancer of the anal canal, i.e. the end section of the gastrointestinal tract (about 4 cm long), and cancer of the anal edge .

Anal canal cancer is mainly squamous cell carcinoma, also called cloacogenic carcinomas. Among anal canal cancers we also distinguish those that are found rarely, e.g .:

• Anal adenocarcinoma (occurs mainly within the rectum) – their presence within the anal canal is rather associated with its infiltration from this area,
• low-differentiated squamous cell carcinomas,
• undifferentiated crayfish,
• small cell carcinomas.

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Both are malignant neoplasms of the anus . In the course of the disease, tumors develop which, as they increase in size, may invade nearby lymphatic and blood vessels, and even adjacent organs. By spreading neoplastic cells from the tumor through the lymph vessels, secondary foci ( anal cancer metastases ) may form in the lymph nodes (mainly perianal, less often in the groin). Anal tumor may cause distant metastases (to other organs), but these metastases are relatively rare. It is estimated that they appear in about 15 percent. cases and are mainly located in the liver or lungs.

What are the causes of anal cancer?

Previous studies have shown that rectal cancer can be caused by many different factors. The increase in the risk of this cancer is influenced, among others, by smoking cigarettes, the negative impact of which in this regard has also been proven in the case of other cancers, e.g. lung, kidney, pancreatic cancer and others. It turns out that it is not diet that has a decisive influence on the development of this cancer. The aforementioned HPV virus is assigned a key role.

HPV 6, 16, 18 infection can cause precancerous lesions in the rectal squamous epithelium, the so-called ASIL that can develop into invasive cancer). Genital warts are an oncogenic factor. People with multiple sexual partners are more likely to suffer from this disease of the anus. Anal sex increases the risk of getting sick. A history of sexually transmitted diseases is an important diagnostic factor for a doctor. Anal cancer in women may be a consequence of cervical cancer or its dysplasia.

Other causes of anal cancer include:

• Bowen’s disease (a type of pre-invasive cancer – in situ, which is located in the epithelium and does not infiltrate deeper tissue structures; in the case of in situ cancer, there is a risk of its progression to an invasive form – infiltrating),
• leukoplakia (white keratosis),
• HIV infection (human immunodeficiency virus),
• chronic immunosuppression (transplant patients, long-term steroid therapy),
• chronic inflammatory processes around the anus (haemorrhoids, fissures, fistulas),
• genetic mutations on chromosomes 3 and 11.

What are the first symptoms of anal cancer?

The prognosis of anal cancer is closely related to its early detection. Effective self-diagnosis plays a key role. A patient who notices the first symptoms should immediately undergo diagnostics that are simple and widely available. You should visit a proctologist or gastroenterologist. Symptoms of anal cancer that may indicate an anus cancer process include :

• lump in the anus – a feeling of obstruction in the anus or a foreign body; an anal tumor in advanced stages may be palpable and even visible;
• feeling of incomplete bowel movement;
• anal itching – burning, stinging, itching;
• mucus from the anus – discharge may be sticky, thick, appear during defecation or independently of it;
• pain in the anus and painful pressure on the stool;
• minor rectal bleeding;
• fecal and gas incontinence,
• lymphadenopathy in the groin.

Symptoms of colorectal cancer may be similar – feeling of incomplete bowel movements (fullness in the abdomen), difficulty passing bowel movements, constipation, discomfort or pain in the abdomen, changing the shape of the stools (so-called pencil stools – long and narrow).

Is it rectal cancer? What kind of research to do?

In order to diagnose cancer of the anal canal or edge, first of all rectal examination should be performed . A finger scan through the anus allows you to feel for changes in the anus, such as lumps. After a short examination, an experienced proctologist will order additional ones – imaging. The next stage is usually palpation and fine-needle biopsy of inguinal lymph nodes – in case of suspicion of pathology within them.

If there is a noticeable change in the anus, the doctor usually recommends taking a tumor sample from the anus for histopathological examination. Further diagnostics assume:

• anoscopy (examination to assess the anal canal and rectal fumice – using a special speculum),
• transrectal ultrasound examination (ultrasound examination performed by inserting a probe into the anus; it allows to determine the depth of tumor infiltration within the tissues),
• endoscopic examination of the large intestine (colonoscopy),
• X-ray (AP and lateral) or computed tomography (CT) of the chest,
• CT or magnetic resonance imaging (MRI) of the abdominal cavity and the small pelvis (allows to determine the size of the tumor, the extent of infiltration, lymph node involvement, the presence or absence of metastases in other organs),
• in women – gynecological examination .

Anal cancer – treatment

For many years, the basic method of treating cancer of the anal canal was the so-called abdomino-perineal resection (APR), which was associated with the creation of an artificial rectum (stoma). Currently, the basic method of therapy in the case of anal canal cancer is the simultaneous use of radio- and chemotherapy with the use of 5-fluorouracil (5-FU) and mitomycin. Local surgical removal of the tumor is performed only when the tumor is well differentiated, its size is less than 2 cm and there are no metastases in the lymph nodes.

A follow-up examination is performed 6-8 weeks after the end of radiochemotherapy (RCHT) to determine the effectiveness of the treatment.

Patients in remission after the initial therapy should undergo follow-up examinations for 5 years (every 3–6 months): per rectum examination , anoscopy, and palpation of the inguinal lymph nodes.

In the case of advanced forms of anal cancer , it is also recommended to perform a chest X-ray and a CT scan of the smaller pelvis as part of control examinations.

When a patient does not achieve final cure after initial radiochemotherapy, the following situations are possible.

• After radiochemotherapy, the biopsy still shows the presence of cancer cells in the original location – there is an indication for repeated radiochemotherapy or perineural resection.
• After RCHT, an initial remission of the disease was achieved, but after some time its relapse in the form of a local recurrence (reappearance of an anus tumor) – patients undergo radiochemotherapy or abdomino-perineal resection.
• Recurrence after RCHT treatment in the lymph nodes – removal of the nodes, possibly radio- or chemotherapy is recommended.
• When a patient has recurrent disease in a site other than the anus (e.g. liver metastases), treatment with the following chemotherapeutic agents is recommended: cisplatin with 5-fluorouracil, carboplatin, doxorubicin and semustin.

In the case of anal edge cancer, depending on its stage, local tumor excision or radio- and chemotherapy are performed.

Anal cancer and anal tumor – prognosis

Rectal cancer accounts for about 1.6 percent of the cancer population. cases of neoplasms located within the gastrointestinal tract. This disease mainly affects people over 60 years of age. Currently, the incidence of this cancer is increasing, and it is more common in men and in people with HIV infection.

In order to determine the prognosis in patients with diagnosed cancer of the anal canal, the so-called TNM classification, which assesses the primary tumor site (T), local lymph nodes (N) and possible distant metastases (M). The prognosis is mainly influenced by the size of the primary tumor and the presence or absence of metastases in the lymph nodes.

Anal edge cancer has a better prognosis than anal canal cancers. The survival time and its quality depend on the size and location of the tumor. The most important prognostic factor, however, is the speed of diagnosis of a rectal tumor and the time of effective treatment from the moment of diagnosis. The development stage is described by abbreviations from T1 to T4. The letter T is an abbreviation of the Latin word tumor. Patients with the titers described as T1 and T2 have the best chance of recovering from the disease. Sources say that up to 90 percent. patients with tumors up to 5 cm in size, described as T1 and T2 tumors, have a chance to survive for 5 years.

In the advanced stage of T4, meaning the tumor infiltrates adjacent organs (e.g. the vagina, bladder), the 5-year survival is less than 50%. The involvement of the lymph nodes worsens the prognosis – the 5-year survival is then estimated at 25–40%.

HPV ( human papillomavirus ) infection plays an important role in the development of anal cancer . Importantly, rectal cancer is not the same as rectal cancer . These terms refer to two separate disease entities that affect different parts of the gastrointestinal tract. It is worth mentioning that in men, HPV can cause cancer of the anus as well as penile cancer.

Rectal cancer means that the cancer process has spread to the end of the large intestine (approximately 20 cm). The risk factors, the group of sick people are similar to the described disease. Diagnosed early is curable to a great extent.

Anal cancer – complications after treatment

Chemotherapy and radiotherapy used to treat anal cancer can cause complications that can be divided into early and late. Early, often very troublesome and lowering the patient’s quality of life are: diarrhea, peeling of the epidermis, erythema, mucositis, pain, myelosuppression ( reduction in the number of bone marrow cells).

Late complications are mainly diseases of the anus:

• anal ulcers
• anal stricture,
• anal fissure,
• fecal incontinence
• necrotic changes.

Research shows that the late toxicity of therapy (RCHT) requires a colostomy in 6-12% of patients. patients.