Is a clinical target volume (CTV) necessary for locally advanced non-small cell lung cancer treated with intensity-modulated radiotherapy? —a dosimetric evaluation of three different treatment plans

Radiotherapy is one of the most important therapeutic strategies for patients with locally advanced non-small cell lung cancer (NSCLC) but the long-term outcomes following treatment remain dismal (1). To examine whether increasing the intensity of radiotherapy improves both local-regional control and overall survival, several trials, initiated by the Radiation Therapy Oncology Group (RTOG), were conducted in which the safety and efficacy of increasing the total radiation dose were determined. However, in the phase III trial RTOG0617 (2), a higher radiation therapy dose of 74 Gy did not improve overall survival and may even have been harmful, because of the increased dose delivered to adjacent normal tissues. Thus, efforts are currently being directed at ensuring an effective radiation dose escalation while reducing the irradiated volumes to limit treatment-associated toxicities