Time Trends in Diagnostic Delay and Waiting Times of Four Patient Cohorts, Diagnosed With Non-small Cell Lung Cancer, Treated With High Dose Radiotherapy.

A large group of non-small cell lung cancer patients is treated with radiotherapy. Delivery of very high radiation doses is needed to obtain local control, but due to the large tumor and nodal volume this is often impossible without causing unrepairable damage to the normal tissue of the mediastinum, spinal cord, esophagus and lung.

Although every tumor is different with respect to the speed with which it grows and spreads, it is obvious that time plays an important role in cancer therapy. Recently it was reported that disease progression or increase of tumor volume occurred during the time interval between diagnosis and treatment.(1, 2) This could lead to a less optimal radiation treatment and consequently have an impact on overall survival. Moreover, the increasing number of diagnostic procedures, aimed at obtaining more accurate information about the tumor extension and biology, as well as the use of more sophisticated but labor intense radiation techniques could prolong the time interval between clinical symptoms and the start of the treatment. However, the influence of new diagnostic procedures or the applied radiotherapy techniques on waiting times is not yet known. The investigators therefore want to investigate 1) time trends in the waiting time for NSCLC patients, 2) the correlation between waiting times and the use of more advanced diagnostic or therapeutic procedures, and 3) the correlation between waiting times and overall survival.

The hypotheses of the study:

1. The diagnostic delay for NSCLC patients has increased during the last 12 years.
2. The preparation time for radiotherapy of NSCLC patients has increased during the last 12 years.
3. Prolonged waiting times are associated with worse overall survival outcome.

The IKL collected data on waiting times and treatment of NSCLC patients treated in 2001 and 2004. These data will be used for this project. In addition, the MAASTRO lung database contains information of patients treated in 2006 and 2010. Additional information about the diagnostic procedure and radiation treatment preparation will be collected by reviewing the patient charts. For this study a data request has to be submitted to the IKL and access to MAASTRO patient data (charts and EMD) is needed.