Self-sampling as the principal modality for population based cervical screening: Five-year follow-up of the PaVDaG study

Cervical cancer is the fourth most prevalent cancer in women worldwide. A common cause of cervical cancers is the human papillomavirus (HPV) which is a group of more than 100 different types of related viruses. HPV infections are very common. There is no treatment for HPV and most HPV infections will go away on their own, especially in younger people. High-risk types of HPV can cause precancerous cells or cancers in cervical cells. Cervical screening process allows detection and treatment of precancer, effectively preventing development of cervical cancer in majority of women. It is now well established that using cervical cytology as the initial screening test does not provide an effective protection against cervical intraepithelial neoplasia grade 3 and cervical cancer (CIN3+). Three screening strategies are recommended by the WHO: cytology, visual inspection with acetic acid (VIA), and HPV detection from cervicovaginal samples.

The majority of women lack access to screening services in many regions. Regular screenings for women over the age of 30 are necessary because precancerous lesions can take years to manifest. Screening should begin sooner for some groups, such as women with HIV, as soon as they are aware of their status and have engaged in sexual activity. Self-sampling includes procuring a kit and taking a vaginal sample on one’s self. Collection can be done privately in a hospital setting or anywhere else. The person sends sample to a lab for testing and receives the results back. The concerned person is connected to subsequent clinical evaluations and therapy if the test is positive. Self-sampling merits careful consideration for usage in regular screening.

Compared to cytology-based cervical screening, primary screening for high-risk human papillomavirus (Hr-HPV) offers superior protection against cervical cancer. However, the longitudinal performance of self-sampling is still unknown. In a new study published in the International Journal of Cancer, Scottish researchers provided one of the first datasets to investigate the long-term performance of Hr-HPV testing with self-taken specimens in women who participated in population-based cervical screening. Dr. Grazyna Stanczuk, Dr. Heather Currie, Dr. William Forson, Dr. Gwendoline Baxter, Dr. James Lawrence, Dr. Allan Wilson, Dr. Timothy Palmer, Dr. Marc Arbyn, and Dr. Kate Cuschieri. The authors found that in their study that women who test negative for Hr-HPV on self-collected samples utilizing a PCR-based test had low 5-year chances of CIN3+. While the relative sensitivity and specificity of the self-sample compared to clinician-sample did not reach unity, the sensitivity for CIN3+ over the follow-up period was still high. It is still detected 95 of a possible 102 cases, even though the sensitivity and specificity of HPV testing were higher in the professional clinical setting taken samples. According to the authors, women who test Hr-HPV negative on self-collected samples are safe to undergo screening every three years for those who are 49 years old or younger and every five years for those who are 50 years old and older.

The current Scottish study limitations include study-specific interventions outside of standard practice, which might have resulted in a higher rate of disease identification. Additionally, the screening cutoff age at the time of enrollment was 20, which was young compared to comparable settings. Colposcopy was not recommended for all Hr-HPV positive women at the initial screening; instead, additional colposcopy for women with normal cytology was only given to those who tested positive for HPV type 16/18, which is subject to partial verification bias.

In conclusion, cervical cancer mortality can be reduced significantly with high-quality screening. the clinical study conducted in Scotland followed a population-based cohort consistently attending primary Hr-HPV testing services related to the regional Scottish health board comprising registration of testing and follow-up results. Additionally, this is the first study to demonstrate self-sampling performance over two screening rounds in women who participate in routine screening. The results are encouraging and indicate that self-sampling-based Hr-HPV screening may work in a manner that is call-and-recall-based, like samples taken by a physician.