Chronic pain in survivors of childhood cancer : a developmental model of pain across the cancer trajectory

The purpose of this article is to describe the current state-of-the-art regarding the co-occurrence of the anxiety disorders and chronic pain. First, we describe the core characteristics of chronic pain and its co-occurrence with the anxiety disorders. Second, we review data on the prevalence of co-occurrence. Third, we describe the mutual maintenance and shared vulnerability models, both of which have been offered to explain the co-occurrence of posttraumatic stress disorder (PTSD) and chronic pain and may have applicability to various other anxiety disorders. Fourth, we provide an integrative review of available research addressing the postulates of these models specific to the mechanisms of anxiety sensitivity, selective attention to threat, and reduced threshold for alarm. We conclude with general recommendations for improving assessment and treatment of patients who present with an anxiety disorder accompanied by clinically significant pain. Given that most of the available evidence has come from studies of PTSD and chronic pain, we provide a detailed agenda for future investigation of the co-occurrence of chronic pain and other anxiety disorders.

Survival for childhood cancer has increased dramatically over the last 40 years with 5-year survival rates now approaching 80%. For many diagnostic groups, rapid increases in survival began in the 1970s with the broader introduction of multimodality approaches, often including combination chemotherapy with or without radiation therapy. With this increase in rates of survivorship has come the recognition that survivors are at risk for adverse health and quality-of-life outcomes, with risk being influenced by host-, disease-, and treatment-related factors. In 1994, the US National Cancer Institute funded the Childhood Cancer Survivor Study, a multi-institutional research initiative designed to establish a large and extensively characterized cohort of more than 14,000 5-year survivors of childhood and adolescent cancer diagnosed between 1970 and 1986. This ongoing study, which reflects the single most comprehensive body of information ever assembled on childhood and adolescent cancer survivors, provides a dynamic framework and resource to investigate current and future questions about childhood cancer survivors.

No studies have estimated the population-level burden of morbidity in individuals diagnosed with cancer as children (ages 0-19 years). We updated prevalence estimates of childhood cancer survivors as of 2011 and burden of morbidity in this population reflected by chronic conditions, neurocognitive dysfunction, compromised health-related quality of life, and health status (general health, mental health, functional impairment, functional limitations, pain, and fear/anxiety).