DIRECTED ANAL PAP USING FLOCKED SWAB BETTER PREDICTS HIGH-GRADE AIN THAN DACRON SWAB

2.50
Hdl Handle:
http://hdl.handle.net/10755/211584
Type:
Research Study
Title:
DIRECTED ANAL PAP USING FLOCKED SWAB BETTER PREDICTS HIGH-GRADE AIN THAN DACRON SWAB
Abstract:
Purpose & Aims:  To compare two cytology collection methods: nylon-flocked swab vs. Dacron swab. Background: Invasive anal cancer (IAC) is a health crisis for gay, bisexual, transgender and other men who have sex with men (MSM). MSM show a 20-40 fold higher risk for disease, especially within the context of HIV and since the introduction of highly active antiretroviral therapy (HAART) (1-4). Cervical cytology using Papanicolaou's staining (Pap test) reduced ICC incidence significantly (5). Although experts recommend anal Pap test every 1-2 years for MSM, and screening strategies using Dacron swab passed blindly through the anus, there is no national consensus for screening and funding is limited.  Specimens are marginally sufficient, requiring diagnostic work-up for any detected atypias, a lower threshold than is set for cervical cytology in women (6-10). Using similar referral thresholds, anal Pap test using Dacron swab shows lower sensitivity and specificity for high-grade dysplasia (9-16). Materials and Methods: Dacron-swab cytology specimens were collected first using standard procedures; subsequently, Nylon Flocked (NF)-swabs were collected through an anoscope inserted just beyond the verge.  Swabs were approximated to the canal, rotated slowly while withdrawn, and placed into preservatives. HRA, with medical biopsy, where indicated, was performed by experienced clinicians.  Pathologists evaluated cytology using the Bethesda Classification System (17, 18), and histology using the International Classification of Diseases for Oncology (19).  HPV genotypes were assessed from cytology specimens using Linear Array (Roche Diagnostic Laboratories, Pleasanton, CA). Maximum likelihood logistic regression was used to summarize the data, to compare NF- and Dacron swab collection methods, and obtain adjusted estimates (20).  The final model included swab collection methods (NF- vs. Dacron-swab), demographic characteristics (age and race), HIV-infection status and, among the infected, the year a CD4 count was first detected below 200 cell/mm3.  Results: Among 58 men tested using the same clinical protocol, 16% (9/58)  Dacron and 10% (6/58) NF-swab specimens were inadequate for cytological evaluation; accordingly, Dacron swabs were 1.6 times more likely to render an unsatisfactory specimen when compared to NF-swabs. Sensitivity and specificity for Pap test showing ASCUS or more severe dysplasia differed for NF- and Dacron swabs.  However, sample size was limited and sensitivity estimates did not achieve significance: 79% (61-97%) and 50% (28-72%) for NF- and Dacron swab respectively.   Specificity associated with NF- and Dacron swab differed similarly: 62% (45-78%) versus 53% (35-71%), respectively. NF-swab increases the number of interpretable assays, improves detection of HG-AIN and increases the specificity of anal Pap testing.  Multivariate analyses suggested NF-swabs better predicted HG-AIN than did Dacron swab: NF-swabs showing >ASCUS vs. no intraepithelial lesion (NIL), OR=2.0 (1.0, 4.3), vs. Dacron swabs, similarly classified, OR=1.37 (0.6, 3.0).  These relationships persisted after controlling for age, race, HIV-infection, and, among the infected, history of CD4+ cell count below 200 cells/mm3. Conclusions: Cytology specimens collected using NF-swab and anoscope to guide placement more often predicted HG-AIN than did Dacron-swab blindly inserted through the anus. Implications: Improved performance of cytology will likely improve professional consensus for screening and the public’s health.
Keywords:
Cytology; Collection methods
Repository Posting Date:
20-Feb-2012
Date of Publication:
20-Feb-2012
Other Identifiers:
5528
Sponsors:
Western Institute of Nursing

Full metadata record

DC FieldValue Language
dc.typeResearch Studyen_GB
dc.titleDIRECTED ANAL PAP USING FLOCKED SWAB BETTER PREDICTS HIGH-GRADE AIN THAN DACRON SWABen_GB
dc.identifier.urihttp://hdl.handle.net/10755/211584-
dc.description.abstractPurpose & Aims:  To compare two cytology collection methods: nylon-flocked swab vs. Dacron swab. Background: Invasive anal cancer (IAC) is a health crisis for gay, bisexual, transgender and other men who have sex with men (MSM). MSM show a 20-40 fold higher risk for disease, especially within the context of HIV and since the introduction of highly active antiretroviral therapy (HAART) (1-4). Cervical cytology using Papanicolaou's staining (Pap test) reduced ICC incidence significantly (5). Although experts recommend anal Pap test every 1-2 years for MSM, and screening strategies using Dacron swab passed blindly through the anus, there is no national consensus for screening and funding is limited.  Specimens are marginally sufficient, requiring diagnostic work-up for any detected atypias, a lower threshold than is set for cervical cytology in women (6-10). Using similar referral thresholds, anal Pap test using Dacron swab shows lower sensitivity and specificity for high-grade dysplasia (9-16). Materials and Methods: Dacron-swab cytology specimens were collected first using standard procedures; subsequently, Nylon Flocked (NF)-swabs were collected through an anoscope inserted just beyond the verge.  Swabs were approximated to the canal, rotated slowly while withdrawn, and placed into preservatives. HRA, with medical biopsy, where indicated, was performed by experienced clinicians.  Pathologists evaluated cytology using the Bethesda Classification System (17, 18), and histology using the International Classification of Diseases for Oncology (19).  HPV genotypes were assessed from cytology specimens using Linear Array (Roche Diagnostic Laboratories, Pleasanton, CA). Maximum likelihood logistic regression was used to summarize the data, to compare NF- and Dacron swab collection methods, and obtain adjusted estimates (20).  The final model included swab collection methods (NF- vs. Dacron-swab), demographic characteristics (age and race), HIV-infection status and, among the infected, the year a CD4 count was first detected below 200 cell/mm3.  Results: Among 58 men tested using the same clinical protocol, 16% (9/58)  Dacron and 10% (6/58) NF-swab specimens were inadequate for cytological evaluation; accordingly, Dacron swabs were 1.6 times more likely to render an unsatisfactory specimen when compared to NF-swabs. Sensitivity and specificity for Pap test showing ASCUS or more severe dysplasia differed for NF- and Dacron swabs.  However, sample size was limited and sensitivity estimates did not achieve significance: 79% (61-97%) and 50% (28-72%) for NF- and Dacron swab respectively.   Specificity associated with NF- and Dacron swab differed similarly: 62% (45-78%) versus 53% (35-71%), respectively. NF-swab increases the number of interpretable assays, improves detection of HG-AIN and increases the specificity of anal Pap testing.  Multivariate analyses suggested NF-swabs better predicted HG-AIN than did Dacron swab: NF-swabs showing >ASCUS vs. no intraepithelial lesion (NIL), OR=2.0 (1.0, 4.3), vs. Dacron swabs, similarly classified, OR=1.37 (0.6, 3.0).  These relationships persisted after controlling for age, race, HIV-infection, and, among the infected, history of CD4+ cell count below 200 cells/mm3. Conclusions: Cytology specimens collected using NF-swab and anoscope to guide placement more often predicted HG-AIN than did Dacron-swab blindly inserted through the anus. Implications: Improved performance of cytology will likely improve professional consensus for screening and the public’s health.en_GB
dc.subjectCytologyen_GB
dc.subjectCollection methodsen_GB
dc.date.available2012-02-20T12:03:41Z-
dc.date.issued2012-02-20T12:03:41Z-
dc.date.accessioned2012-02-20T12:03:41Z-
dc.description.sponsorshipWestern Institute of Nursingen_GB
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