Anus cancer (anal cancer) – a malignant new growth of the anal channel. Blood allocations from back pass, pain at defecation, violation of a chair, an anal itch can be symptoms of cancer of an anus. Diagnosis of cancer of an anus is based on results of a manual research, a rektoromanoskopiya, PAP dab, biopsy of suspicious education. In most cases cancer therapy of an anus at various stages includes the combined himioluchevy therapy, radical operation - a rectum extirpation with installation of a constant kolostoma.
Long time the proktologiya considered anus cancer as a form of cancer of rectum and only in the middle of last century in connection with introduction of the term "anal channel" was allocated in an independent nosology. The malignant tumors which are settling down in an anatomic zone between the upper edge of an anorektalny ring and border of transition of an anus to perianalny skin belong to cancer of an anus and the anal channel. The tumors which are localized distalny edges of an anus are classified as a new growth of perianalny skin.
Malignant defeat of an anus makes 1-2% of all cases of a colon cancer, i.e. 1 case on 100 000 population. More often cancer of an anus is observed in age group 50 years, mainly at men are more senior. Homosexual sexual communications increase prevalence of cancer of an anus among men by 35 times, HIV infection – twice.
Classification of cancer of an anus
Cancer of an anus and the anal channel includes a wide range of histologic forms that is caused by complex structure of anal area and a variety of types of an epithelium of which it consists (multilayered flat, transitional, cylindrical in a rectum and ferruterous in anal glands).
The most frequent form is the epidermoidny (planocellular) cancer of an anus (55% of cases) developing distalny the rectal and anal line from external fabrics of the anal channel inclined further to an ulceration. Kloakogenny (bazaloidny) cancer of an anus (25-30% of cases) arises proksimalny the rectal and anal line, in a zone of transition of a cylindrical epithelium to flat. Adenogenny cancer of an anus (adenocarcinoma) develops from cages of a ferruterous epithelium of anal glands. Emergence of the combined ferruterous and planocellular cancer of an anus is possible (for example, mukoepidermoidny). The melanoma can arise from cells of skin and mucous that causes dark color of a tumor.
Anus cancer reasons
The reliable reasons leading to development of cancer of an anus are unknown, however it is possible to mark out some risk factors increasing probability of its emergence. Contamination of VPCh (especially high degree of an onkogennost) leads to emergence of genital warts (condylomas) around an anus and on a uterus neck at women that can provoke further development of cancer in these zones. The condition of an immunodeficiency at HIV infection, after organ transplantation, treatment by immunosuppressants creates conditions for oncological process in the field of an anus.
Frequency of developing of cancer is increased by constant irritation and an inflammation of an anus at chronic diseases (cracks of back pass, anorektalny fistulas, polyps, hemorrhoids, a proktita, a leukoplakia), anal sexual contacts. The harmful chemicals inhaled at tobacco smoking increase risk of development of cancer of an anus in the smoker by 9 times. To cause cancer of an anus and the anal channel performing radiation therapy at cancer therapy of a neck of a uterus, prostate gland, rectum, bladder can. The age is more senior than 50 years is risky concerning malignant transformation of cages and fabrics of an anus.
Anus cancer symptoms
At early stages cancer of an anus is followed by emergence of nonspecific clinical symptoms. The most frequent complaint at cancer of an anus is blood impurity availability in Calais or anal bleeding. Also pains in the field of back pass, at first insignificant are noted at defecation, then more expressed and constants, with irradiation in a stomach bottom, genitals, a hip. At an anus cancer invasion in the back arch of a vagina there is rektovaginalny fistula; at germination the dizuriya phenomena develop in a prostate gland and an urethra at men; at destructive processes in an anal sphincter the incontience of kalovy masses is noted.
Many patients are disturbed by pressure and feeling of a foreign matter in the field of back pass accompanied with the constant or periodically developing anal itch. The pain syndrome and an itch at cancer of an anus are caused by a rich innervation of an anal zone, a strong spasm of muscles and irritation of a mucous membrane of back pass by mucous or purulent allocations from the pathological center.
Development of cancer of an anus leads to violation of a chair (more often to locks), need of a natuzhivaniye at defecation, to increase in perianalny and inguinal lymph nodes. There can be not healing sores in the anal channel and around an anus. At the started forms of cancer of an anus weakness, a loss of appetite, loss of weight is observed.
Diagnosis of cancer of an anus
The correct early diagnosis of cancer of an anus is complicated due to the lack of characteristic signs and a wide range of local and general symptoms. At suspicious manifestations comprehensive examination - the general fizikalny survey of the patient, manual, endoscopic, ultrasonic, cytologic and histologic researches is shown.
Careful survey of anal area and manual anorektalny research in various provisions (lying on a back, a knee - elbow situation, "on cards", at women – bimanualny); allow to estimate a condition mucous an anus and a rectum, to establish existence of new growths, their borders and the sizes. The palpation of inguinal area for definition of increase in lymph nodes is carried out.
Performance of a rektoromanoskopiya (an anoskopiya, a proktoskopiya) with simultaneous carrying out an aim biopsy of suspicious sites is obligatory. Rektoromanoskopiya allows to specify localization, the size and type of a new growth. Carry out a cytologic research of anal dab – the PAP test, if necessary – a punktata of inguinal lymph nodes, and also a histologic research of the fabrics taken at an endoscopic biopsy.
At confirmation of the diagnosis of cancer of an anus for definition of distribution (stage) of tumoral process the additional examination including a kolonoskopiya and an irrigoskopiya, a transrectal ultrasonografiya, ultrasonography, MPT or KT of abdominal organs, lymph nodes, a thorax X-ray analysis is conducted. Cancer of an anus should be differentiated from other diseases of intestines, such as hemorrhoids, polyps, anorektalny cracks, etc.
Cancer therapy of an anus
In cancer therapy of an anus apply various methods: surgical, radiation (radiation) therapy, chemotherapy which choice depends on localization and the size of a tumor, the stage of a disease accompanying pathology, results of primary treatment (existence of a recurrence).
Now the standard of cancer therapy of an anus and the anal channel is the combined himioluchevy therapy. Planocellular cancer of an anus has rather high radio sensitivity that allows to reach elimination of a tumor by means of ionizing radiation and at the same time to keep locking function of an anal sphincter. Apply remote radiotheraphy perednezadny and promezhnostny water, and also intracavitary and interstitial brachytherapy radio needles with 60so. Also subject to radiation inguinal lymph nodes. For strengthening of radiative effects on a tumor use a local hyperthermia (a tumor warming up to 42–43 °C by means of intracavitary radiation of ultrahigh frequency).
The chemotherapy oral or intravenous medicines strengthens medical effect of radiotheraphy, influencing at the same time a tumor and metastasises in regionarny lymph nodes, but has side effect. In the combined cancer therapy of an anus apply a combination of the low-dosed remote radiation therapy and chemotherapy mitomitsiny C and 5-ftoruratsily, allowing to achieve in most cases at the small sizes of a tumor full treatment and to carry out effective preoperative preparation.
Efficiency of the conservative combined cancer therapy of an anus does it by a surgery alternative - belly to a rectum extirpation with formation of a constant kolostoma. At this radical surgery broad excision of a tumor and the tissues of intestines, anal sphincter adjoining to it, sometimes and perianalny area is carried out. At identification of metastasises of cancer of an anus in inguinal lymph nodes performance of an inguinal limfadenektomiya is necessary. The indication for radical surgery is emergence of a recurrence of a tumor after the carried-out himioluchevy therapy and development is purulent - necrotic complications.
Forecast and prevention of cancer of an anus
Depending on an anus cancer stage surgical treatment can help to reach long remission: 5-year survival after operation in the absence of regionarny metastasises makes 55-70%, at their existence – about 20%. The combined himioluchevy treatment allows to cure anus cancer at 80% of patients, with a tumor with a diameter less than 3 cm. A recurrence at the same time arises less than in 10% of cases. Assessment of results of the carried-out cancer therapy of an anus and the prevention of a recurrence of a disease requires further observation of the proctologist.
As measures of prevention of cancer of an anus and decrease in risk of HIV and VPCh-infection serves use of condoms at casual sexual contacts, presence of the constant sexual partner, refusal of smoking, regular screening inspections (the PAP test and an anoskopiya).