PURPOSE Cancer-related lymphedema (LE) is an incurable condition associated with lymph-involved cancer treatments and is an increasing health, quality of life (QOL), and cost burden on a growing cancer survivor population. This review examines the evidence for causes, risk, prevention, diagnosis, treatment, and impact of this largely unexamined survivorship concern. METHODS PubMed and Medline were searched for cancer-related LE literature published since 1990 in English. The resulting references (N = 726) were evaluated for strength of design, methods, sample size, and recent publication and sorted into categories (ie, causes/prevention, diagnosis, treatment, and QOL). Sixty studies were included. Results Exercise and physical activity and sentinel lymph node biopsy reduce risk, and overweight and obesity increase risk. Evidence that physiotherapy reduces risk and that lymph node status and number of malignant nodes increase risk is less strong. Perometry and bioimpedence emerged as attractive diagnostic technologies, replacing the use of water displacement in clinical practice. Swelling can also be assessed by measuring arm circumference and relying on self-report. Symptoms can be managed, not cured, with complex physical therapy, low-level laser therapy, pharmacotherapy, and surgery. Sequelae of LE negatively affect physical and mental QOL and range in severity. However, the majority of reviewed studies involved patients with breast cancer; therefore, results may not be applicable to all cancers. CONCLUSION Research into causes, prevention, and effect on QOL of LE and information on LE in cancers other than breast is needed. Consensus on definitions and measurement, increased patient and provider awareness of signs and symptoms, and proper and prompt treatment/access, including psychosocial support, are needed to better understand, prevent, and treat LE.