Cancer is a leading health problem in the modern world. In addition to the repercussions of cancer on individual lives, its serious impact on families and society should be considered. Considering this widespread impact, the importance of psychotherapy sessions for individuals diagnosed with cancer can be clearly observed. Although existential therapies have increased their effectiveness in Turkey and other countries in recent years, there are not enough studies on the practice of existential therapy in individuals diagnosed with cancer. In this study, the contribution of existing therapy practice to psychotherapy sessions with individuals diagnosed with cancer was revealed to overcome the current deficiency in literature. Based on the four world theory of existing therapy, the importance of addressing the worlds of individuals diagnosed with cancer from an experiential perspective in psychotherapy is evident.