Cancer survivorship research: opportunities and future needs for expanding the research base.

The National Cancer Institute has determined that there are >10 million people alive today in the United States who have been diagnosed with cancer, and nearly two thirds have survived >5 years after their initial diagnosis (1). With the current advances in early detection and treatment, certain types of cancer that were once uniformly fatal, such as large majority of pediatric cancer, testicular cancer, and Hodgkin lymphoma, are now potentially curable. Additionally, patients with other common neoplasms, such as breast and colorectal cancers, enjoy improved disease-free and overall survival as a result of adjuvant therapy. The number of cancer survivors in the United States has tripled since 1971 and is growing at the rate of 2% every year (2). It is therefore imperative to focus on the health and well-being of this large and ever-increasing population of cancer survivors. Cancer survivors represent a remarkably diverse group, characterized by a wide range of cancer diagnoses, clinical/biological features of their primary cancer, treatment exposures, social and demographic characteristics, and other comorbid health conditions. For example, whereas breast, prostate, and colorectal cancer account for >50% of all cancer survivors, >5 million survivors have been diagnosed and treated for other forms of cancer (Fig. 1). Furthermore, cancer is largely a disease of older persons, and thus, the majority of cancer survivors are older than 65 years (3). Thus, survivorship for the vast majority of cancer survivors occurs in a background setting of comorbid conditions, with a potentially greater effect on the health status of elderly cancer survivors (3).