Psycho-oncology is an interdisciplinary field at the intersection of physical, psychological, social, and behavioral aspects of the cancer experience for both patients and caregivers. Also known as psychiatric oncology or psychosocial oncology, researchers and practitioners in the field are concerned with aspects of individuals' experience with cancer beyond medical treatment, and across the cancer trajectory, including at diagnosis, during treatment, transitioning to and throughout survivorship, and approaching the end-of-life. Founded by Jimmie Holland in 1977 via the incorporation of a psychiatric service within the Memorial Sloan Kettering Cancer Center in New York, the field has expanded drastically since and is now universally recognized as an integral component of quality cancer care. Cancer centers in major academic medical centers across the country now uniformly incorporate a psycho-oncology service into their clinical care, and provide infrastructure to support research efforts to advance knowledge in the field. Psycho-oncology deals with psychological reactions to the experience of cancer, the behavioral component of coping with cancer as well as health behavior change including preventive medicine, and social factors that are associated with diagnosis and treatment of cancer, including communication with providers and loved ones and social support. In addition, research related to the influence of psychosocial factors on biological disease-related processes has burgeoned over the past two decades. Much research takes a biopsychosocial approach to account for the interplay between biological, psychological, and social factors in coping with cancer. The integration of psycho-oncology into routine oncologic care represents a major step forward in terms of care for the whole patient. Psychological Diagnosis and treatment of cancer is known to influence psychological well-being to a significant degree. Rates of psychological distress are elevated for most individuals who have been diagnosed with cancer when compared to population norms. Common psychological reactions to cancer are mood and anxiety-related concerns. Elevated rates of depression and anxiety in response to a cancer diagnosis is often attributable to uncertainty regarding mortality and well as going through arduous treatments and concerns related to functional interference and body-image or other self-concept related distress. Understanding how individuals react psychologically to cancer is important to support their overall well-being and maximize quality of life during treatment and beyond. While the prevalence of psychological disturbance in reaction to cancer is relatively high when compared to population norms, many individuals report fairly stable psychological well-being through the cancer trajectory and some even report improved psychological well-being. Depression