Raising cancer awareness among adolescents can increase their confidence in identifying cancer symptoms and develop healthy habits. This study tested the effectiveness of cancer education based on a new model among high schoolers. A non-randomized control group pre-post-test design study was conducted among 313 pairs of adolescent students and their knowledge-sharing partners in Lalitpur, Nepal. A baseline test was conducted before the education program, and it was followed up at two weeks and three months. Results were measured using a chi-square test, binary logistic regression, and a two-way repeated-measures ANOVA. There was a significant interaction effect of intervention and time on students’ knowledge, beliefs, self-esteem, and practice, along with a change in some scores of knowledge-sharing partners. Joint assignment supported the idea of diffusion of information within the family and in the neighborhood. The peer group discussion could encourage active learning and help students to participate visibly in problem-solving and reflecting more sustainably. Time constraints, lack of human resources, and support groups, might limit this program’s usage; however, preparing guidelines, and connecting communities, organizations, hospitals, volunteer health workers, and survivors can help make it more sustainable and approachable.