Background:
Anal cancer screening guidelines exist only locally or nationally for some at-risk population like MSM living with HIV. In sub-Saharan Africa, there is no access to anal cytology analysis and proctologic consultations. There is a need to implement HPV detection strategy to screen most at-risk patients. The aim of this study was to evaluate anal self-sampling (ASS) for HPV detection compared to anal swab carried out by the practitioner (ASP).
Methods:
The ANRS 12400 DepIST-H cohort included 200 MSM in Togo, half living with HIV, prospectively followed up with yearly anal sampling and proctologic exam. During the month-12 visit, ASS was proposed to MSM before clinical consultation. A flyer explaining the procedure accompanied the FloqSwab for ASS, which was discharged into eNAT. The practitioner conducted afterwards anal exam, anal sampling with a cytobrush discharged in ThinPrep. All samples were analyzed by the Virology lab of Bichat Hospital (Paris, France) with AnyplexII for detection of 14 high-risk HPV (HR-HPV). HPV16 viral load was quantified with in-house qPCR.
Results:
A total of 188 MSM were included, median age of 23 years, 99% of participants found the ASS procedure was easy to carry out and 60% of them would prefer ASS to ASP at next visit while 19% had no preference. ASS was suitable for HPV detection since only 5% samples were uninterpretable compared to 7% for ASP (p=0,77). Overall, at least one HR-HPV was detected in 83% (n=148/178) and 77% (n=135/176) of ASP and ASS, respectively, and 28% and 26% were positive for HPV16. ASP and ASS showed substantial agreement (89.7%) for HR-HPV detection with Kappa’s coefficient of 0.66) (Figure 1). The agreement for HPV16 was 90.3% (Kappa’s coefficient = 0.75). HPV16 median viral loads were higher in ASS than ASP (7652c/mL vs 575c/mL respectively, p=0.009). Regarding the 16 samples with discordant result for HPV16 detection, HPV16 viral load was low (160c/mL for ASS and 155c/mL for ASP in median).
Conclusions:
To our knowledge, this is the first time ASS and ASP are compared for HPV detection performance at the same time. The concordance of the two sampling methods, the acceptability of ASS and the facility to implement self-sampling are in favor of using ASS for HPV detection in anal cancer screening programs. The HPV detection implementation worldwide for cervical cancer screening following the WHO’s 2020 guideline will enable anal cancer screening implementation in LMIC.
