Vienna-II ring applicator for distal parametrial/pelvic wall disease in cervical cancer brachytherapy: An experience from two institutions: Clinical feasibility and outcome.

Abstract

Recent evidence from EMBRACE shows that around 16% patients with locally advanced cervical cancer (LACC) have residual tumor in distal parametrium (DP) and pelvic wall disease (LPW) after concurrent radio-chemotherapy (CCRT). Adequate target coverage with standard brachytherapy approaches represents a challenge. Therefore, we modified the Vienna I applicator with an add-on cap allowing for additional oblique needles into the DP/LPW (Vienna II). We report here the feasibility and clinical outcomes using Vienna II applicator in LACC patients treated in 2 institutions. 69 patients with residual disease in DP/LPW after CCRT were accrued. FIGO (2009) stage was 26% IIB, 52% III, 15% IVA, 7% IVB (para-aortic nodes). At diagnosis 91% had disease involving DP/LPW. After CCRT, patients underwent image guided adaptive brachytherapy (IGABT) using Vienna II applicator. IGABT details, acute complications, dose volume parameters and clinical outcome variables were compiled and analyzed. Residual DP/LPW disease at BT was found in 90% patients. Median total number of needles were 7 [3-15], oblique 4 [1-7]. Manageable intraoperative utero-vaginal complications occurred in 8 patients and manageable arterial bleeding in 6 patients during removal. Mean distance between tandem and outer contour of CTV_HR was 38 mm and mean CTV_HR (±SD) volume was 69 ± 32 cm³. The mean D₉₀ CTV_HR was 86 ± 7 Gy (EQD2) and mean (±SD) D_2cm³ (Gy, EQD2) 86 ± 12, 68 ± 7, 68 ± 9 for bladder, rectum and sigmoid respectively. Actuarial LC, PFS, OS at 3/5 years was 76/72%, 56/50%, 62/54% and G3-4 late toxicities (n = 23) were observed in 14 patients (20%). IGABT using Vienna II applicator allows for appropriate target coverage in tumors extending into DP/LPW at the time of BT. Clinical use is feasible and results in good local control, DFS and OS with moderate rate of acute and late ≥G3 toxicity.