Impact of Delays in Lung Cancer Treatment on Survival.

Timely care is an important dimension of health care quality, but the impact of delays in care on lung cancer outcomes is unclear. Quantifying the impact of delays in cancer treatment on survival is necessary to inform resource allocation, quality improvement initiatives, and lung cancer guidelines. Review of the available literature demonstrated significant heterogeneity between studies in terms of the impact of delay. Frequently paradoxical results were reported, with delay being associated with improved survival in patients with advanced disease. However, significant methodologic flaws were identified in many studies, which probably is the reason for the paradoxical results. The most significant methodologic limitations identified were incorrectly controlling for final pathologic stage (a mediator in the causal chain from delay to survival), failure to control for confounding by acuity of cancer presentation, and failure to consider effect measure modification. The effect of delay on survival probably varies by stage. The impact of delays is lowest for subcentimeter nodules, probably highest in stage II disease, and low in patients who are only eligible for palliative care. Precise quantification of the impact of delay is not currently possible. Given the available evidence, quality metrics for the timeliness of lung cancer care should focus on local barriers to care. These metrics should be carefully designed to take into account clinical-radiographic stage at initial presentation.