Are sleep continuity disturbance and fatigue prodromal symptoms of cancer development?

Sleep continuity disturbance (also known as insomnia) and fatigue are common complaints of individuals diagnosed with cancer. Traditionally, many have believed that sleep continuity disturbance and fatigue are caused, in large measure, by the impact of the cancer diagnosis and treatment. Recent prospective research suggests however, that sleep continuity disturbance and fatigue may actually precede a cancer diagnosis. We suggest that sleep continuity disturbance and fatigue may in fact represent prodromal symptoms of cancer. We review the current perspectives of this sequence of events and present a revised schematic that accounts for the role of biological, behavioural, and cognitive factors that contribute to the development and maintenance of sleep continuity disturbances in cancer patients. Monitoring emergent and unexplained patient-reported fatigue, sleepiness, and insomnia may serve as early warning signs of new onset cancer, providing opportunity for early detection and early intervention.