This review focuses on the
early diagnosis of anal cancer and its precursor lesions through routine
screening. A number of risk-stratification strategies as well as screening
techniques have been suggested, and currently little consensus exists among
national societies. Much of the current clinical rationale for the prevention
of anal cancer derives from the similar tumor biology of cervical cancer and
the successful use of routine screening to identify cervical cancer and its
precursors early in the disease process. It is thought that such a strategy of
identifying early anal intraepithelial neoplasia will reduce the incidence of
invasive anal cancer. The low prevalence of anal cancer in the general
population prevents the use of routine screening. However, routine screening of
selected populations has been shown to be a more promising strategy. Potential
screening modalities include digital anorectal exam, anal Papanicolaou testing,
human papilloma virus co-testing, and high-resolution anoscopy. Additional
research associating high-grade dysplasia treatment with anal cancer prevention
as well as direct comparisons of screening regimens is necessary to develop
further anal cancer screening recommendations.
…[T]here are populations with disproportionate prevalence
of anal cancer that are more conducive to group-wide screening.
Immunosuppressed patients are increasingly recognized as one of the groups at
highest risk for anal cancer[13,37]. Much of this recognition has developed over the
rise of the HIV/AIDS epidemic in the last three decades. Infection with HIV is
associated with a 30-fold increased lifetime risk in anal cancer and a 4-fold
increase in 5-year mortality[37,38]. Although sexual practices - particularly
anoreceptive intercourse - have been previously associated with anal cancer,
recent studies have shown that the risk of anal cancer in HIV-positive
individuals exists independently of sexual practices[39,40]. The risk of anal dysplasia progression appears
to correlate directly with degree of immunosuppression as measured by T cell CD4+ count with
a cell count less than 200 cells/mm3 most
closely associated with increased prevalence[41-43]. Surprisingly though increased access to highly
active antiretroviral therapies has not eliminated the increased risk of anal
cancer in the HIV-infected population. It is thought that immune system
restoration does not entirely eliminate the increased risk of dysplastic
changes and then antiretroviral treated patients are living longer thereby
increasing the lifetime interval risk of disease incidence[44]...
Below: San Francisco algorithm for
anal cancer screening of high-risk patients. ASC-US: Atypical squamous cells of
undetermined significance; LSIL: Low-grade squamous intraepithelial lesions;
HSIL: High-grade squamous intraepithelial lesions; Pap: Papanicolaou; HRA:
High-resolution anoscopy; AIN: Anal intraepithelial neoplasia
Below: Johns Hopkins Hospital algorithm
for anal cancer screening of high-risk patients. Pap: Papanicolaou; HRA:
High-resolution anoscopy; ASC-H: Atypical squamous cells of undetermined
significance, cannot rule-out high-grade dysplasia; AIN I: Anal intraepithelial
neoplasia I; PCP: Primary care physician; LSIL: Low-grade squamous
intraepithelial lesion; AIN II: Anal intraepithelial neoplasia II; AIN III:
Anal intraepithelial neoplasia III.
Full article at:
By:
Ira L Leeds,
Sandy H Fang, Ravitch Division, Colon and Rectal Surgery, Department of
Surgery, Johns Hopkins Hospital, Baltimore, MD 21287, United States
Author contributions: Leeds IL and Fang SH contributed to
conception and design; Leeds IL contributed to data collection and analysis,
and drafting manuscript; Fang SH contributed to critical revision.
Correspondence to: Ira L Leeds, MD, MBA, Ravitch Division,
Colon and Rectal Surgery, Department of Surgery, Johns Hopkins Hospital, 600 N
Wolfe Street, Tower 110, Baltimore, MD 21287, United States. ude.imhj@sdeeli
More at: https://twitter.com/hiv insight
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