Self-collection might be used to complement current and future cervical cancer screening programs that utilize human papillomavirus (HPV) testing, provided that specific programmatic and pragmatic issues are addressed (1, 2). However, as noted in ref. 1, “If the relative sensitivity decreases to 0.90 combined with either a 3 percentage points extra attendance or the absence of higher primary background risk women, QALYs are lost when more than 30–20% of the regular attendees switch.”
A meta-analysis reported similar performance for HPV testing or self-collected or provider-collected specimens, especially when PCR-based assays are used for the HPV testing, suggesting that the loss in sensitivity would not be an issue (2, 3). However, these data must be interpreted with caution. For many of these studies, self-collection was done at the clinic. The real-world performance of self-collection and HPV testing, in which the specimens are collected at home without clinical “supervision,” is unknown but likely to be less accurate than self-collection in the artificial setting of a clinical study. Women might fail to provide a specimen or might not collect the optimal specimen. It is easy to imagine that 20% to 30% of attendees switching to home-based self-collection out of convenience but experiencing a 10% or greater loss in sensitivity for cervical precancer and cancer compared with provider-collected specimens on a population level.
Self-collection and HPV testing will likely play a vital role in increasing the number of women who get a high-quality screening against cervical cancer globally. In lower-resource settings, where high-coverage Pap-based screening will never be established successfully, self-collection and HPV testing may provide the means to reach the population without requiring women to get a pelvic examination and without the use of valuable and limited clinic facilities. Early evaluations in Argentina (4) demonstrated great promise. In high-resource settings, the challenge is to reach the ∼10% to 30% of the population who do not routinely participate or participate at all in screening without substantially reducing the cancer prevention benefits to the general population. Targeted approaches through programs that specifically serve these underserved populations may be the best solution to increase coverage while minimizing the crossover of attendees to self-collection. Engagement through community health workers (CHW) might further increase participation in screening of the underscreened in a targeted fashion (5). CHWs might serve as patient navigators to the screen-positive women to ensure timely follow-up. In this way, we might further reduce the population burden of this highly preventable cancer.
See the Response, p. 1296
Disclosure of Potential Conflicts of Interest
P.E. Castle reports receiving speakers bureau honoraria from Cepheid and is a consultant/advisory board member for Cepheid, ClearPath, Genticel, GE Healthcare, Guided Therapeutics, Hologic, Inovio, and Teva Pharmaceuticals.