Cancer of the anal canal and perianus
The last 20 years, there has been a constant increase in the incidence of anal cancer. This is mainly due to the rise of HPV infection rate. Anal cancer has always been commoner in women but a steady and significant rise in anal cancer incidence has been observed recently, especially in gay population.
It has been proven that anal cancer is caused by HPV, especially 16 and 18 subtypes. There are high risk groups for anal cancer and they are related to immunosuppression and HPV infection. High risk groups consist of people with anal intercourse, HIV seropositive, people with multiple sexual partners, cancer or dysplasias of lower female genital tract, patients under immunosuppressive treatment, transplant patients, autoimmune diseases and inflammatory diseases of bowel. Smoking is an aggravating risk factor. There is a 50% probability of dysplasias and 10% probability of anal cancer in HIV-seropositive patients.
Prevention of anal cancer
The prevention of anal cancer is easy. Primary prevention is vaccination of male and female population until 26 years. Vaccination of high risk groups in older age is nowadays advised. Secondary prevention consists in diagnosis of precancerous lesions with anal cytology and high resolution anoscopy. During secondary prevention, precancerous lesions that progress into cancer (HSIL or HGAIN) are diagnosed and should be ablated.
Diagnosis of anal cancer
Anal cancer in advanced cases is seen as a hard mass that can bleed. The diagnosis is made with biopsies. Preoperative staging is ensured with endoanal ultrasound and magnetic resonance.
Treatment of anal cancer
Very early cases of anal cancer can be treated with local resection. Combined radio- chemotherapy is the appropriate treatment of advanced cancers that infiltrate anal sphincters. Extensive abdomenoperineal resection of anus is considered only if combined modality therapy fails to eradicate the disease.