Ηigh Resolution Anoscopy (HRA) is a high magnification endoscopic examination of the anal canal and the skin around. It is performed for diagnosis and subsequent treatment of HPV induced dysplasias (precancerous conditions) which may progress into cancer. HRA is performed in high risk groups for anal cancer, especially if anal cytology shows abnormal cells in the internal or external lining (epithelium) of anus.
HRA technique derives from colposcopy which is used for the identification of precancerous dysplasias in the external female genitalia. HRA is quite different from colonoscopy or sigmoidoscopy, which cannot effectively investigate HPV infection and dysplasias. Especially flat lesions, which tend to be premalignant, cannot be detected without acetowhitening and high magnification.
HRA is performed in outpatient basis, without any anesthesia, and lasts about 15 minutes. Before examination, a gauze soaked with dilute acetic acid (vinegar) is inserted through a hollow tube (anoscope) into the anal canal for 2-4 minutes. After removal of the gauze, the anoscope is reinserted and the anal canal and perianal skin are examined under magnification searching for areas with features of HPV infection or of high grade dysplasias (grey staining, mosaicism, coarse punctuation, abnormal blood vessels, etc.). Acetic acid and Lugol staining enables detection of suspicious lesions and help physician decide where to take biopsies. Biopsies are the most significant phase of HRA and should be done after careful photo-documentation. Biopsies are taken in order to diagnose and subsequently treat premalignant changes that are susceptible to develop into anal cancer. In case that biopsies show high-grade dysplasia (HGAIN), HRA examination is redone for electroablation under local anesthesia of dysplasias after correlation with previous HRA mapping and photo- documentation. Significant post examination complications such as bleeding or fever are extremely rare. Anal intercourse should be avoided for 2-3 weeks.
Experienced healthcare providers performing HRA are quite rare worldwide because of steep learning curve, special training and the extensive infrastructure needed. HRA is available in US, in Australia and in a few European countries. HRA has been performed exclusively In Greece in our proctology clinic since 2012.