Interpreting Clinical Trials in Lung Cancer: Impact of Methodology and Endpoints

The design and analysis of clinical trials are crucial if we are confidently to answer important questions regarding the treatment of patients with non-small cell lung cancer. Survival, response, and quality of life (QoL) are considered the key endpoints of oncology clinical trials. Survival is the primary endpoint of most randomized, phase III clinical trials, but small improvements in survival are difficult to detect without a sufficiently large sample size. Meta-analysis is a useful technique to increase statistical precision and better estimate the magnitude of a treatment effect. Although survival data guide treatment choice, the objective response is generally the parameter used to evaluate treatment in the clinic, despite its inherent unreliability. The objective response rate remains an important outcome for early phase clinical trials. QoL, which is a particularly important trial endpoint if survival differences are unlikely may, however, be a more relevant outcome in the clinic. Several validated QoL tools are available for use both in trials and in daily practice, but many clinicians do not routinely assess QoL when evaluating an individual patient's response to treatment. Recent advances in electronic technology make capturing QoL data at each office visit not only possible but practical, reliable, and useful for both patients and clinicians. Therefore, although survival, response, and QoL can all be relevant clinical trial endpoints, QoL may be the most relevant endpoint to assess in the clinic.