Comparison between self sampling and provider collected samples for Human Papillomavirus (HPV) Deoxyribonucleic acid (DNA) testing in a Nigerian facility

Introduction The multiple visits required for an effective Pap smear screening program is difficult to replicate in many developing countries. This precludes early diagnosis and care for patients with cervical cancer and contributes to its high mortality in these countries. HPV screening has higher specificity and high negative predictive value and has the advantage that materials can be self-collected, which permits the screening of women who for various cultural and religious reasons would be reluctant to come to the clinic to expose themselves for screening. The aim of the study was to assess the degree of agreement between self sampling for HPV DNA with samples collected by a health provider. Methods Each respondent selected from women presenting for cervical cancer screening underwent both self- and provider sampling for HPV DNA testing using Hybribio GenoArray. Results Of the 194 women screened, 12 (6.2%) and 19 (9.8%) had HPV on self sampling and provider col-lected samples respectively. The commonest HPV type seen using both techniques was HPV 58 (2.6%). Multiple HPV genotypes were seen in 1 (0.5%) and 5 cases (2.6%) of provider and self-collected samples respectively. The high risk-HPV detection rate was 7.2% when self sampled and 6.8% when sampled by the provider. There was moderate correlation between both sampling techniques (κ = 0.47, 95% CI: 21.3 - 72.3%, P < 0.05). Conclusion Our study shows moderate correlation between both sampling techniques. Larger multicentre studies will be needed to provide results generalisable to the Nigerian population. Keywords: Pap smear, HPV screening, cervical cancer, sample collection, self-sampling, provider collected, PCR, HPV DNA, Ile-Ife Nigeria.


Introduction
Cancer of the cervix is the third leading cause of cancer deaths in women worldwide following breast and colorectal cancers. Over the past 30 years however the incidence and mortality rates have declined in developed countries. This is largely due to effective and efficient cervical cancer screening programs using pap smears and HPV DNA testing [1]. Testing for high risk HPV DNA has been shown in randomized controlled trials to offer 60-70% more protection against invasive cervical carcinomas over cytology and allows for extension of screening intervals [2,3]. These factors make cervical cancer the most preventable gynecological cancer [4]. In recent times however there has been concerns about reduction of coverage resulting from non-attendance of screening programs in some western countries [5,6]. Reasons given include embarrassment, anticipated pain, forgetting to make appointments, lack of awareness of recommended screening interval, dislike of the health care giver and lack of time. Self sampling for HPV DNA testing provides an alternative to sampling by health care givers and indeed has been shown to improve attendance rates [5]. Its results are also comparable to those of provider collected samples depending on the sample brush or polymerase chain reaction (PCR) technique used [7]. Eighty percent of cases and 88% of deaths attributed to cervical cancer occur in low to middle income countries, with sub-Saharan Africa having the highest burden of the disease (age standardized incident rate of 50/100, 000 compared to 5/100, 000 in high income countries) [1]. Barriers to screening in developing countries include competing health needs, limited human and financial re-sources, poorly developed healthcare services, disempowerment of women, widespread poverty, war and civil strife [3]. Due to these barriers in screening, visual inspection under acetic acid (VIA) is common among these populations.
Unfortunately VIA performs poorly when compared to conventional cytology and HPV DNA testing [1]. HPV DNA testing on self sampled specimen might therefore serve as a reasonable alternative for screening in low to middle income health countries because of its potential to overcome some of these barriers [3]. Its feasibility however has not been assessed in many of these countries. The aim of this study was therefore to assess the degree of agreement between self and provider collected samples for HPV DNA.

Results
A total of 194 women were recruited for the study.

Discussion
Cancer of the cervix continues to be a public health problem in developing countries with higher age standardized incidence rates, life time risk and mortality rates than western societies.  [14]. PCR based tests have also been shown to be more sensitive than testing with hybrid capture assays [15]. The most prevalent HPV DNA subtype varies in different geographical locations. In this study, HPV 58 and 39 were the commonest subtypes seen. This is in contrast to HPV 35 and 16 in Ibadan, 35 and 52 in Abuja, HPV 52 in Kenya, and HPV 16 and 66 in Chile [9,[16][17][18]. In a study done in China, the HPV infection rate was found to be significantly higher in women in the southwestern region (19.9%) compared to other regions (11.1% northeastern, 12.9% central). In that study HPV-52 was the most prevalent genotype in the central and northeast regions while HPV 16 was the most prevalent type seen in the northwest and southeast regions [19]. This variability is similar to another study conducted in Mexico where there was a difference in the distribution of the HPV genotypes between two regions of the southwest pacific coast [20].
These differences are most likely due to epidemiological factors and might explain the discordance between our findings and those of other parts of S.W Nigeria.
Self-sampling for HPV DNA, as an alternative to sampling by health care givers, has been well received in some studies. In one report of Hispanic respondents, the overall experience was reported as excellent by 33.7% and very good by 30.8%. Only 2.6% reported a poor of fair experience. The clarity of instructions, ease of use of kit and understanding of results were aspects of the experience the respondents found favourable [21]. A study in Norway showed that attendance rates increased from 23.2% to 33.2% when nonattenders had a choice between home-based self-sampling and appointments by a health provider. The majority of respondents in the study found the self-sampling procedure to be easy, not painful, embarrassing or scary [6]. Self sampling is also well received in Nigeria. A study done in Abuja showed a higher proportion of women in the self-collection group completing the HPV tests compared to those invited to the health facility for specimen collection by a health worker. In that study the majority of respondents found the sample device easy to use and chose selfsampling as the preferred method to be used in the future [16]. In Kenya where lack of transportation, cost and long hospital queues are reported deterrents to hospital-based screening, self-sampling has been proposed as a viable alternative for ensuring cervical screening [22]. Most studies report good concordance between selfsampling and sampling by health care providers. In this study there was moderate concordance between self-collected and provider collected samples. A good correlation was also seen in a Canadian study with concordance rate of 85.7% and kappa coefficient of 0.54 [23].