Program Information
Dose Escalation in LogoRegionally Advanced Cervical Cancer Using Hybrid Inverse Planning Optimization in HDR Brachytherapy
Senni Andavar*, Dr Vikas Roshan , Arashdeep Dhiman , Dr Jagmohan Singh , Shri Mata Vaishno Devi Narayana Superspeciality Hospital, Jammu, Jammu and Kashmir
Presentations
TU-C1-GePD-T-1 (Tuesday, August 1, 2017) 9:30 AM - 10:00 AM Room: Therapy ePoster Lounge
Purpose: The purpose of this study is to investigate the effectiveness of HIPO in dose escalation in advanced cervical cancer treatment by HDR Brachytherapy system.
Methods: For these study we have taken 11 patients CT images who already underwent EBRT (50.4Gy/28#) followed by Image guided based intracavitary radiotherapy (21Gy/3#) in our institution. The clinically delivered brachytherapy dose plans were normalized based on traditional Point A prescription. For inverse planning, the critical organs, GTV, High Risk-CTV and Intermediate Risk-CTV were delineated based on GEC-ESTRO guidelines. The hybrid inverse plans were generated for each patient using Oncentra Version4.5 treatment planning system. Dosimetric parameters, absolute volumes like 0.1cc, 1cc and 2cc of normal tissues receiving the reference dose and linear quadratic radiobiological model-EQD2 for tumor and OAR indices were evaluated for both EBRT and ICRT. The summation of physical dose to EBRT and ICRT to the tumor was equivalent to EQD2 dose of 78.1Gy in both the plans.
Results: A prescription dose of 7Gy per fraction was prescribed to point A in standard plans. The volume of HR-CTV ranged from 28.5cc to 57.02 with the mean of 38.71cc. For HR-CTV, D90 was optimized to aimed at least 7Gy. The D90 was higher (6.9Gy±0.11) in standard plan as compared to HIPO (6.67Gy±0.21).Inverse planning reduced the absolute volume (2cc) dose to Bladder (3.39Gy±0.87, p=0.00013), rectum (2.91±1.05, p=0.0099) and sigmoid (1.56±0.65, p=0.0058) without compromising dose coverage to the target volume.
Conclusion: We have found that plans generated by HIPO are clinically comparable with traditional loading pattern in terms of target dose. Moreover the dose escalation recommended by both GEC-ESTRO and ABS for the target EQD2 of 85 to 90gy is possible in HIPO plan without increasing the OAR toxicity. The care should be given while delineating the target volumes.
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