História prévia de realização de teste de Papanicolaou e câncer do colo do útero: estudo caso-controle na Baixada Fluminense, Rio de Janeiro, Brasil

Exposure Definition in Case-Control Studies of Cervical Cancer Screening: A Systematic Literature Review

The first step in evaluating the effectiveness of cervical screening is defining exposure to screening. Our aim was to describe the spectrum of screening exposure definitions used in studies of the effectiveness of cervical screening. This systematic review included case-control studies in a population-based screening setting. Outcome was incidence of cervical cancer. Three electronic databases were searched from January 1, 2012 to December 6, 2018. Articles prior to 2012 were identified from a previous review. The qualitative synthesis focused on describing screening exposure definitions reported in the literature and the methodologic differences that could have an impact on the association between screening and cervical cancer. Forty-one case-control studies were included. Six screening exposure definitions were identified. Cervical cancer risk on average decreased by 66% when screening exposure was defined as ever tested, by 77% by time since last negative test, and by 79% after two or more previous tests. Methodologic differences included composition of the reference group and whether diagnostic and/or symptomatic tests were excluded from the analysis. Consensus guidelines to standardize exposure definitions are needed to ensure evaluations of cervical cancer screening can accurately measure the impact of transitioning from cytology to human papillomavirus-based screening and to allow comparisons between programs.

Advancements in the Application of Ultrasound Elastography in the Cervix

Ultrasound elastography is a modern imaging technique that has developed rapidly in recent years. It enables objective measurement of tissue stiffness, a physical property intuitive to the human sense of touch. This novel technology has become a hotspot and plays a major role in scientific research and academic practice. Presently, ultrasound elastography has been used in the identification of benign and malignant tumors in superficial organs, such as breast and thyroid, providing clinically accurate diagnosis and treatment. The method has also been widely used for the liver, kidney, prostate, lymph nodes, blood vessels, skin and muscle system. In the application of cervical lesions, ultrasound elastography can distinguish normal cervix from abnormal cervix and differentiate benign from malignant lesions. It can significantly improve the diagnostic specificity for cervical cancer and is also useful for assessing infiltration depth and stage of cervical cancer, as well as predicting chemoradiotherapy treatment response. For cervical evaluation during pregnancy, ultrasound elastography is useful for assessing cervical softening and predicting premature delivery and outcome of induced labor. This article reviews the principles of ultrasound elastography as well as the current status and limitations in its application for cervical lesions and the cervix during pregnancy.