Cancer survivorship research: State of knowledge, challenges and opportunities

INTRODUCTION: Seminal advances in early detection of and treatment strategies for cancer have led to burgeoning numbers of cancer survivors. While most therapeutic modalities for cancer are beneficial and lifesaving, they are associated with adverse long-term and late sequelae. MATERIALS AND METHODS: Literature review using MEDLINE to identify studies examining adverse medical outcomes and post-treatment follow-up care among long-term survivors. Emerging concepts in survivorship research such as definitional issues, research paradigms and methodologic concerns were also examined. RESULTS: Long-term or late adverse sequelae are more prevalent, serious, and persistent than expected in survivors of pediatric and adult cancer, but remain understudied especially among those diagnosed as adults. Follow-up care relevant to survivorship outcomes is neither standardized nor guideline or evidence based for most adult cancers, and optimal practices have yet to be defined. DISCUSSION: Adverse sequelae contribute to burden of illness, health care costs, and decreased length and quality of survival. To-date, very few studies have compared survivor outcomes pre-and post diagnosis. It is critical to examine under-researched questions and understudied survivor groups. Regular follow-up care and monitoring of health status post cancer treatment should 1) permit the timely diagnosis and treatment of adverse outcomes; 2) enable timely diagnosis and treatment of recurrences; 3) facilitate screening and early detection of second cancer(s); 4) allow for detection and management of co-morbidities; and 5) provide the opportunity for preventive strategies such as lifestyle changes. Research findings to-date underscore the need for continued cancer survivorship research that will: inform our understanding of the mechanisms underlying adverse sequelae; lead to the design of less toxic treatments; test the effectiveness of interventions - medical, pharmacologic, and behavioral - that reduce adverse outcomes; test models of post-treatment follow-up care; develop an evidence base for optimal follow-up care practices; and inform survivor and provider decision making.