The IARC Perspective on Cervical Cancer Screening

In May 2018, the World Health Organization (WHO) called for the elimination of global cervical cancer as a major public health priority, with a 2-pronged approach focusing on effective vaccination against human papillomavirus (HPV) and the screening for and treatment of early cervical cancer. Cervical cancer is considered largely preventable through these programs; however, it continues to be disproportionately prevalent in countries with the lowest values on the Human Development Index. The most significant determinants of participation in screening are access, socioeconomic status, ethnic group, health insurance status, and education level. This review by the International Agency for Research on Cancer (IARC) Working Group of 27 scientists from 20 countries aims to assess the evidence on the effectiveness of primary screening in reducing the incidence of cervical cancer and the risk of death associated with cervical cancer.

Cervical cytological analysis, known better as the Papanicolaou test, is the most widely used screening test and was recommended in the 2005 IARC Handbook on cervical cancer screening. Since then, aggregate evidence from multiple studies shows that this method consistently reduces the incidence and mortality associated with cervical cancer, especially when associated with an organized screening program (group A). Compared with conventional cytology, liquid-based cytology had a similar or higher sensitivity for detection of cervical intraepithelial neoplasia (CIN) of grade 2 or higher and likewise reduces incidence of and the mortality associated with cervical cancer (group A). The use of acetic acid for visual inspection (VIA) and HPV nucleic acid testing were both concluded to reduce mortality associated with cervical cancer (group A). The Romanowsky-Giemsa staining method has a lower cost of single examination and is widely available compared with the Papanicolaou test in some regions; however, there is insufficient evidence that it reduces the incidence or the mortality of cervical cancer (group C).

The harms associated with cervical cancer screening include pain and discomfort, anxiety related to the procedure and results, stigma and shame, and physical harm associated with subsequent diagnostic procedures. The Working Group concluded that the benefits of HPV nucleic acid testing or with cytologic analysis outweigh the harms for women 30 years or older. When comparing the relative harms and benefits of different testing modalities, it was concluded that the greater reduction in the mortality and incidence of cervical cancer following HPV DNA testing compared with traditional cytology outweighs the harms related to the increase in positive results and colposcopy referrals. Likewise, HPV DNA testing results in greater benefits and is less subjective than visualization with acetic acid. Compared with cotesting, defined as simultaneous HPV DNA testing and cytology, HPV DNA testing alone has minimal difference in risk of CIN2+ and CIN3+, and the benefits of cotesting do not outweigh the additional harms.

The results of this guideline demonstrate several approaches to cervical cancer screening were received group A recommendations and were effective in reducing incidence of and the mortality associated with cervical cancer. HPV testing alone is the most effective method when weighing the balance of benefits and harms.