Methodological challenges of symptom management research in recurrent cancer

Completion of first-line treatment is an important milestone for adults newly diagnosed with cancer. However, for many adults, the cancer experience of the 21st century does not end with the completion of initial treatment. Decreased functional status, distressing symptoms, and residual effects of treatment impact the daily lives of cancer survivors. Cancer has evolved into a chronic illness, in which a disease-free period may be followed by recurrent cancer. Researchers face challenges in the design and analysis of symptom management studies in recurrent disease. Residual effects can preclude a true "baseline" measurement of the symptom(s) of interest to the researcher. In addition, as cancer survivors age, they are more likely to have comorbid conditions that increase the likelihood of developing toxicities and residual symptoms that are specific to cancer treatments. Research studies of cancer-related symptoms in adults with recurrent disease pose many methodological challenges. Selection of appropriate study design, sample inclusion and exclusion criteria, measures of comorbidity and symptoms, and advanced analysis techniques are among the strategies proposed to address these methodological challenges.