One of the non-communicable diseases that has a major impact on women's health worldwide is cancer. WHO predicts the number of cancer patients in the world will continue to rise to 30.2 million cases by 2040. Of the 19.3 million cancer cases in the world, the most common disease is breast cancer as much as 11.7%. This study aims to determine the effect of knowledge and attitude of adolescent girls towards breast self-examination (BSE). The research design is a Quasy Experiment research design with One Group Pretest-Posttest Design. The research design is without a comparison group (control) with the pretest posttest group design approach method, namely research by giving a pretest (initial observation) The number of samples is 58 people taken by total sampling technique. The results of this study found that of the 58 adolescent girls, most were 14 years old (58.6%), did not have a history of breast cancer (100%) and were exposed to media information (32.8%). The mean knowledge before and after the intervention had different values, with the latter showing an increase after the intervention on knowledge. Based on bivariate analysis using the Wilcoxon test, there is an effect of BSE education in increasing adolescent girls' knowledge of BSE, with statistical test results p-value 0.000 <0.05 and attitude p-value 0.000 <0.05. There is an influence of external variables on breast self-examination (BSE), the variables that most influence breast self-examination (BSE) are knowledge and attitude with statistical test results <0.05.

Health Education, Breast Self-examination (BSE), Knowledge and Attitude