Ask an answerable question (PICO)：
Pap smear screening once every year for women over the age of 30 is included in the National Health Insurance in Taiwan. From 2006 to 2016, the prevalence of cervical cancer has decreased from 7.4 to 5.5 (person/0.1 million) [1]. Regular screening is believed to yield better result [3], but with 20% of false negative result. Therefore, scholars suggest errors could be corrected by multiple screenings [2]. However, the result of cost-effectiveness analysis suggested performing smear screening once every three years instead of every year. Frequent screening may increase the possibility of over-treatment and medical costs [5]. There is a low correlation between a negative Pap smear and a stage III cervical cancer or carcinoma in situ within 45 months. It is recommended to extend the screening interval [8;11] .
The Method and Analysis of Literature Review：
Based on the empirical nursing procedures, answerable clinical questions were proposed, using "PICO" to conduct keyword search: Cervical Screening, Interval, Cervical Cancer etc. The study applied MeSH to search for synonyms in PubMed, MEDLINE, Cochrane Library and Airiti Library online database. All the articles were limited to publications written in English in the recent decade. Three articles met the search queries and PICO, and among them two articles were systematic literature reviews and one cohort study. The review tool used in the study was the (CASP) developed by National Health Service of the U.K., suitable for systematic literature reviews and cohort studies.
Critical Appraisal：
The study employed CASP to closely evaluate the validity, importance, impact, and practice of the articles collected. According to Oxford CEBM 2011 Levels of Evidence, two systematic literature reviews were graded as level 2 and the cohort study level 2. Among ten questions evaluated with CASP, paper written by Meggiolaror (2016) had five items rated as “uncertain” and two “negative,” indicating the result invalid. Most of the items of the other two papers were rated as “yes,” indicating that the results could be used as references [4; 7].
Results, Conclusions and Recommendations：
The result proved Pap smear screening performed once every two or three years could provide better protection and raise the willingness of screening. It also helped patients detect earlier stage cervical cancer and start early treatment. The screening interval could be extended to once every five year. Therefore, the study recommended Pap smear screening once every two or three years for women over the age of 30.
