Advances in the early detection, diagnosis, and treatment of cancer have improved dramatically over the last twenty years. With ongoing survivorship, people with cancer are increasingly expected to assume a greater role in managing their own care. Yet one of the challenges of self-management is maintaining a balance between achieving a good quality of life and the limitations imposed by cancer. Specifically, it is difficult for some patients with cancer to maintain a sense of meaning and purpose in life. This is known as the existential challenge of cancer. Traditional means of delivering psychological support cannot currently meet the demands of an increasing number of people living with cancer as a chronic illness. Alternative ways are urgently needed to offer timely, accessible, and personalized support. My research focuses on the development and testing of tools that can help patients to understand the personal meaning of cancer and its impact on their life goals and priorities. I develop and evaluate different ways of offering psychosocial support with an existential focus to patients living with cancer. In my research, I use interviews and questionnaires to understand how patients experience cancer. I then use these findings to develop interventions that are sensitive to their unique and changing needs. Examples of these interventions are in-person counselling delivered by a health care provider; self-administered workbook; self-administered web-based support; and support provided by community-based groups. Once developed, I rigorously evaluate these different ways of treating the human side of cancer in clinical trials to determine how effective they are when compared to the usual care received by cancer patients. These studies aim to contribute useful and practical knowledge to improve the systematic delivery of psychosocial health care to all adults diagnosed with cancer.