4   Noncoplanar Stereotactic Body Radiation Therapy for XXXX : Potential to Improve Tumor Control and Late @entity137 .

@entity1 @entity135 @entity137 @entity0 @entity5 @entity189 @entity320
PURPOSE: To evaluate the potential benefit of 4   radiation therapy in recurrent, locally advanced, or metastatic @entity135 treated with stereotactic body radiation therapy (SBRT). METHODS AND MATERIALS: Twenty-seven @entity1 with 29 @entity5 who were treated using SBRT were included. In recurrent disease (n=26), SBRT was delivered with a median 44  Gy (range, 35-44  Gy) in 5 fractions. Three @entity1 with @entity320 , metastatic @entity0 , and primary @entity189 received 35  Gy, 22.5  Gy, and 40  Gy in 5 fractions, respectively. Novel 4   treatment plans were created for each @entity1 to meet the objective that 95% of the planning target volume was covered by 100% of the prescription dose. Doses to organs at risk (OARs) and 50% dose spillage volumes were compared against the delivered clinical SBRT plans. Local control (LC), late @entity137 , @entity5 ( @entity5 ), and normal tissue complication probability were determined. RESULTS: Using 4   plans, mean/maximum doses to all OARs were reduced by 22% to 89%/10% to 86%. With 4   plans, the 50% dose spillage volume was decreased by 33%. Planning target volume prescription dose escalation by 10  Gy and 20  Gy were achieved while keeping doses to OARs significantly improved or unchanged from clinical plans, except for the carotid artery maximum dose at 20-Gy escalation. At a median follow-up of 10  months (range, 1-41  months), crude LC was 52%. The 2-year LC of 39.2% approximated the predicted mean @entity5 of 42.2%, which increased to 45.9% with 4   plans. For 10-Gy and 20-Gy dose escalation, 4   plans increased @entity5 from 80.1% and 88.1% to 85.5% and 91.4%, respectively. The 7.4% rate of grade >= 3 late @entity137 was comparable to the predicted 5.6% mean normal tissue complication probability for OARs, which was significantly reduced by 4   planning at the prescribed and escalated doses. CONCLUSIONS: 4   plans may allow dose escalation with significant and consistent improvements in critical organ sparing, @entity5 control, and coverage.
