Kategorie: Kolorektální karcinom
Téma: XVI. Kolorektální karcinom
Číslo abstraktu: 140
The role of anal screening cytology has entered the epidemiologic and cytopathologic literature as a topic of interest over the
last 15 years. The increasing frequency of premalignant anal lesions and anal cancer among the high risk groups of population (homosexual men, HPV and HIV infected, transplant patients etc) was the main causative factor. The cytological diagnostic categories of anal dysplasia are those of atypical cells of uncertain significance (ASCUS), low grade squamous intraepithelial lesions (LSIL) and high grade squamous intraepithelial lesions (HSIL). Classification according to Bethesda system has been advised, implying similarity of anal dysplasia and cancer to those encountered in the cervix.
Natural exfoliative cytology was introduced as a cost effective screening method („anal Pap smear“). Standard colonic preparation is not required, but the rectum should be emptied prior to obtaining the anal sample. Some have used direct smears onto glass slides with immediate wet fixation; other centers, however, employ immediate insertion of the scraping device into liquid fixative for thin layer preparation.
Screening programs have implemented anal cytological screening in high risk populations. The screening for ASIL consists
of a swab for anal cytology. Anal cytology had a 69% sensitivity among HIV positive men and 47% among HIV negative men
at their first visit. Its sensitivity was 81% for the former and 50% for the latter group for all subsequent visits combined. In comparison, the sensitivity of cervical cytology is 80%. The specificity of anal cytology was 59% in HIV positive men and 92% in HIV negative men when including ASCUS.
The conclusion is that screening HIV positive homosexual men annually and HIV negative homosexual men every 2-3 years
for HPV induced anal disease would prolong significantly life expectancy in high risk groups of population.
A clear management strategy is still lacking, nevertheless pilot programs should be established offering anal cytology screening programs for HIV positive homosexual men as well as for any macroscopically suspicious anal lesion, such as anal warts, condylomas, chronic irritation, chronic fissures and pruritus anii. The aim of these screening pilot programs should be to detect anal cancer at an early and curable stage and to aquire long term prospective data on the progression and prognosis of anal dysplasia (AIN) as well as to identify AIN patients who are eligible for local therapeutic management.
Datum přednesení příspěvku: 24. 4. 2007