Review Chronic treatment-related pain in cancer survivors

1. Introduction The prevalence of cancer is increasing globally with an estimated 17 million new cases projected for 2020 [40]. Despite the fear associated with this diagnosis, there is cause for optimism. As new treatment options emerge, and old therapies are refined to have greater antitumor effects, survival rates have increased dramatically. This evolution in the battle against cancer, however, is leading to changes in the way patients experience cancer pain. In the past, the tumor was the underlying cause of pain for most patients. Currently, treatment-related chronic pain syndromes are being seen with greater frequency. Surgery, radiotherapy, chemotherapy, hormonal therapy and other treatments, in combination or alone, have the potential to lead to severe persistent pain states. These painful syndromes can seriously impair quality of life, and may reduce adherence to potentially curative therapies, leading to reduced survival. There are many causes of pain in the person with cancer. The focus of this review will be on four chronic pain syndromes that result from the treatment of cancer; most of these have garnered little attention to date from the pain community. However, it is hoped that increased awareness will lead to better experimental models and greater understanding of the underlying mechanisms of these painful conditions, ultimately leading to superior prevention and treatment options.