THE ROLE OF HYBRID BRACHYTHERAPY IN MANAGEMENT OF LOCALLY ADVANCED CERVICAL CANCER: DOSIMETRIC STUDY AND INITIAL RESULTS

Purpose: The aims of this study were to investigate the clinical feasibility and report our preliminary treatment outcomes combined intracavitary/interstitial brachytherapy (IC/IS BT), using a hybrid applicator magnetic resonance imaging (MRI)based planning in patients with locally advanced cervical cancer. Materials Methods: Between January 2017 December 2018, eight uterine cancer treated primary radiation therapy including BT. Patients distant metastasis other than para-aortic lymph node spread excluded from study. A for guidance parametrial needles was used perform highdoseratebrachytherapy (HDR BT) MRIbased pre-planning. Parametrial extent disease or large residual these judged exceed coverage limit intracavitary alone. number needles, chosen guiding holes through ovoids, insertion depths based on disease. We investigated dosimetric gain by comparing IC/IS optimized plan clinical) an additionally generated without needle use (ICstudy). Results: system proved be feasible all 32 fractions. Fletcher interstitial 6mm Utrecht consists IC tandem two ovoids thatserves as template insertion. MRI preplanning performed week before implant 5 cases day ofapplication place 3 cases. Four placed per fraction, overall total 152 used. Significant differences (IC/IS) (IC study) derived dose application target volume D90 high-riskclinical (D90 CTV HR) 90.1Gy (IC/ISclinical) vs 85.36 Gy average 4.74 Gy. Likewise, sparing organs at risk (OAR) differed significantly bladder D2cc:82,5 Gy(IC/ISclinical) vs95.7 rectum D2cc: 65,5 67.8 study).With follow-up 27,25 months (range 18–34 months): no patient experienced local relapse, three distantmetastasis them died, acute complications such bleeding organ penetration occurred due placement, one developed recto-vaginal fistula. Conclusions: Our experience indicates that significant extending up distal third parametriaafter externalbeam is allows excellent control low rate morbidity.