Background: Radiation therapy is the main player in management of locally advanced head and neck squamous cell carcinoma. Intensity-modulated radiation therapy IMRT does not compensate for anatomical changes or tumor shrinkage during the treatment course. Adaptive radiation therapy may be the suggested solution to consider these changes.
Aim of the Work: Evaluate dosimetric and clinical effects of adaptive RT. in advanced head and neck squamous cell carcinoma.
Patients and Methods: A total number of 49 patients with a provisional diagnosis of locally advanced squamous cell carcinoma of head and neck treated with definitive concurrent chemo-radiotherapy with the original plan optimized to deliver 70 Gy. All patients were re-simulated at a median dose of 42Gy (range, 37.0-44.1) and shifted to adaptive plan.
Results: With adaptive re-planning, the median gross target volume and boost planning target volume improved with 0.74%, 1.66% respectively. The maximum dose to ipsi-lateral, contra-lateral parotid, spinal cord and brain stem had a median reduction of 3.86%, 5.32%, 3.5% and 5.28, respectively. Median size reduction of ipsilateral and contra lateral parotid was 13.62% and 17.68% respectively. With a median follow up 18 months ranging from (6.5 to 31) months, The median progression-free survival has not been reached, while the cumulative P.F.S. at 1year and 2 years were 89.7 % and 70.2% respectively.