Brief overview
- What is anal carcinoma? Malignant tumor in the area of the anal verge and anal canal.
- Symptoms: Mostly nonspecific symptoms; possible palpable changes on or in the anus, blood in the stool, itching, burning, or pain during bowel movements.
- Is anal cancer curable? Yes, the chances of cure are higher the earlier the cancer is detected and treated.
- Incidence: Rare cancer that affects about 1-2 out of every 100,000 people each year.
- Diagnosis: Proctoscopy, endosonography, but also ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), among others. For a definite diagnosis: biopsy.
- Treatment: Options include surgery, radiation therapy, and chemotherapy. The choice of the optimal treatment depends on the exact type and spread of the tumor.
What is anal carcinoma?
Frequency of anal carcinoma
Anal carcinoma is rare. It represents less than five percent of all cancers of the gastrointestinal tract (gastrointestinal malignancies). Approximately one to two in 100,000 people develop new cases of anal cancer each year.
Overall, anal cancers are about two to five times more common than anal marginal cancers. Men are about four times more likely to develop the latter than women. Women, on the other hand, develop anal canal carcinomas more often.
How can you recognize anal cancer?
Anal cancer does not cause specific symptoms that clearly indicate the disease. Possible symptoms of anal cancer are:
- palpable changes on or in the anus, e.g. nodular indurations
- bleeding in the anal area
- blood in the stool
- itching and burning at the anus
- poorly healing or non-healing wounds (ulcer) in the anal region
- altered bowel habits (e.g. constipation, diarrhea)
- pain, especially during defecation (due to narrowing of the anal canal)
- Difficulty controlling bowel movements (to the point of fecal incontinence).
Anal carcinoma or hemorrhoids?
Those affected often misinterpret existing complaints and think that they are harmless hemorrhoids. These enlarged vascular cushions at the anus cause similar symptoms such as itching or bleeding.
Metastases in anal cancer
If the anal carcinoma progresses further, cancer cells can detach and migrate via the lymphatic channels to nearby lymph nodes, for example, and become lodged. This results, for example, in severe swellings in the groin (lymph node metastases).
The cancer cells can spread even further in the body via the blood and lymph channels. In addition to the lymph nodes, the liver and lungs are also most frequently affected by metastases from anal carcinoma.
Is anal cancer curable?
Since it usually grows slowly, the majority of anal carcinomas have not yet metastasized to other parts of the body when they are first diagnosed. Thus, the chances are good that the tumor can be cured in the early stages. In patients with localized disease, about 90 percent are still alive after five years (5-year survival rate).
What causes anal carcinoma?
The risk of contracting the disease is particularly high after infection with so-called high-risk types of the HP virus (HR-HPV). These have a high oncogenic – i.e. cancer-promoting – potential. In over 90 percent of anal carcinomas, physicians can detect genetic material of HPV types 16, 18, 31 and 33, predominantly HPV 16.
Lifestyle-related and other risk factors
Another risk factor is a chronically damaged, inflamed anal area – for example, due to chronic infections, fistulas or fissures. People suffering from Crohn’s disease, a chronic inflammatory bowel disease, are more likely to develop anal cancer than healthy people.
Anal carcinoma can also develop more easily after past radiation therapy to the pelvic area.
Risk factor: weakened immune system
However, the risk group also includes patients who take immunosuppressive drugs (immunosuppressants). Doctors prescribe such drugs, for example, after organ transplants (e.g. kidney transplants), in autoimmune diseases (e.g. multiple sclerosis) or in inflammatory rheumatic diseases.
Examinations and diagnosis
Taking the medical history (anamnesis)
First, the doctor discusses and collects all important medical information in a personal interview. For example, he asks about complaints, previous and underlying diseases. He also pays particular attention to risk factors such as smoking or immunosuppressive drugs.
Physical and proctological examinations
The interview is followed by a detailed physical examination. In the case of anal carcinoma, palpation of the anal region (digital-rectal examination) is particularly important. Through this uncomplicated examination, doctors can detect many tumors growing there. The doctor also checks whether lymph nodes in the groin are enlarged.
Proctoscopy: The doctor examines the anal canal and the lower rectum. This allows him to view abnormalities from the palpation examination.
Rectoscopy and colonoscopy: Often, the doctor will perform an endoscopy of the rectum, i.e. of the entire rectum and anal canal (rectoscopy), or of the entire colon (colonoscopy). The main purpose of this is to rule out further tumor foci in the intestine.
Anal endosonography: An ultrasound examination performed not from the outside through the skin, but from the inside via the anal canal (using a thin ultrasound probe). It is usually not painful. With the help of the ultrasound images, the doctor can see above all how far smaller tumors in particular have already penetrated into surrounding tissue and whether lymph nodes there look suspicious.
Biopsy
During proctological examinations, the physician immediately takes tissue samples from a suspicious area (biopsy). The samples are then examined for fine tissue in a special laboratory.
The physician attempts to completely remove easily accessible growths that are up to two centimeters in size (especially anal marginal carcinomas).
Further imaging
Once a diagnosis of anal carcinoma has been made, the physician will usually order further imaging examinations. These include magnetic resonance imaging (MRI) of the pelvis, including the anal canal. This is the best way to assess how far the growth has extended into the soft tissue, especially in the case of a larger growth.
All examinations are used to determine the exact stage of anal carcinoma (staging).
Stages of anal carcinoma
Depending on the progress of the disease, anal carcinoma is divided into different stages. The respective tumor stage has a significant influence on the choice of the optimal therapy. Doctors can also use it to assess the prognosis.
In anal carcinoma, the following tumor stages are officially distinguished:
Stage II: The tumor is localized but larger than two centimeters (IIA: 2-5 cm, IIB: > 5 cm). It has not yet grown into adjacent tissue and has not spread.
Stage IIIA: The anal carcinoma is no more than five centimeters in size. However, cancer cells have already spread to nearby lymph nodes, such as those in the groin.
Stage IV: At this stage, metastases have already formed in more distant parts of the body, such as in the liver, lungs and lymph nodes even outside the pelvis.
Treatment of anal carcinoma
Treatment options for anal cancer include radiation, chemotherapy and surgery. The exact procedure depends on the tumor stage. The goal is to remove all tumor cells and, if possible, to preserve natural anal function – that is, to be able to control bowel movements.
Therapy of anal canal carcinoma in stage I
At this stage, anal canal carcinoma is usually treated with radiochemotherapy. This means that doctors irradiate the cancer site (radiotherapy) and also give anti-cancer drugs (cytostatics, chemotherapy). This combination is usually more effective, especially since both methods support each other (chemotherapy, for example, makes the anal carcinoma more sensitive to radiation).
For chemotherapy, the active ingredients mitomycin, 5-fluorouracil (5-FU), cisplatin and capecitabine have proven effective in practice. These cytotoxins sometimes inhibit further cancer growth. Incidentally, the chemotherapy dose during radiation is usually lower than during chemotherapy alone. As a result, the cytostatic side effects are also usually lower.
Therapy of anal marginal carcinoma in stage I
Therapy of anal carcinoma in stages II-III
In stages II and III, doctors basically treat both forms of anal cancer in the same way. Affected patients receive combined radiochemotherapy directly. This represents the most effective treatment method. However, if radiochemotherapy or even radiotherapy alone cannot be performed, doctors perform surgery.
Side effects of radiochemotherapy for anal cancer
Therapy of stage IV anal carcinoma
In the case of stage IV metastasized anal carcinoma, a cure is hardly possible. The physicians of the different departments work out the remaining treatment options in close coordination.
In addition, since anal carcinoma is already far advanced in the fourth stage, patients receive information on palliative care. It accompanies through the intense physical, psychological and spiritual circumstances in the last phase of life.
Accompanying psycho-oncological care
Artificial bowel outlet for anal carcinoma
An artificial bowel outlet (colostomy) is rarely necessary for anal cancer. Sometimes, however, doctors advise it in order to relieve the anal canal. The stoma can be useful, for example, if the tumor very severely constricts the anal canal or if there is persistent inflammation.
Doctors also place a colostomy in advanced cases of anal carcinoma that can no longer be cured, in order to continue to allow defecation.
Therapy control
Surgical removal of an anal carcinoma and combined radiochemotherapy take place in a specialized center. This ensures close-meshed care and monitoring.
A complete remission – that is, a complete regression of the tumor – is confirmed by your doctor with a final MRI. If the treatment of the anal carcinoma was successful, the follow-up care follows.
Anal carcinoma or rectal carcinoma
They may originate from the mucous membrane of the rectum. Doctors then speak of deep-seated rectal cancer. This is where treatment differs. Usually, doctors first perform radiochemotherapy (neoadjuvant). This is followed by surgical intervention.
Course of disease after initial therapy
The tumor then often grows in the same place as the first time (locoregional recurrence). Doctors clarify the recurring tumor (recurrence) again by a biopsy. This is usually followed by MRI and PET/CT of the pelvis.
How extensive the surgeons operate depends in particular on where the residual or recurrent tumor is growing. Doctors usually remove anal marginal carcinomas in a smaller operation. In the case of remaining anal canal carcinomas or recurrences there, on the other hand, they operate more extensively.
Aftercare and rehabilitation
After successful therapy, regular follow-up examinations are necessary to detect a possible flare-up of the cancer at an early stage. Follow-up care for anal carcinoma usually extends over five years. The following examinations take place:
- Patient interview, physical examination and procto/rectoscopy every three months in the first year, then quarterly to semi-annually depending on the case.
- Computed tomography at least once after six months if affected individuals had stage II or higher anal carcinoma; supplemented by PET scan, if necessary.
Patients can also take advantage of oncological rehabilitation for the period after treatment. Training measures there serve, for example, to absorb possible physical limitations as a result of the treatment.
Can anal cancer be prevented?
Anal cancer can only be prevented to a limited extent. The focus is on infections with the sexually transmitted HPV viruses, which play a major role in the development of the disease. However, the use of condoms only prevents infections to a limited extent.
Doctors advise particularly vulnerable patient groups – for example, HIV-infected or organ-transplanted patients – to undergo regular and, if necessary, more frequent preventive examinations. Ask your doctor whether this makes sense in your case.
In addition, refrain from smoking. A healthy lifestyle can generally prevent cancers such as anal carcinoma.
