Kidney‐sparing whole abdominal irradiation in Wilms tumor: Potential advantages of VMAT technique

Abstract

Purpose To present a preliminary clinical experience and a dosimetric comparison of kidney‐sparing volumetric modulated arc therapy (VMAT) with three‐dimensional conformal radiotherapy (3D‐CRT) for whole abdominal irradiation (WAI), in the setting of Wilms tumor (WT) treatment. Materials and methods From a total of 20 consecutive WT cases treated with adjuvant irradiation, seven were submitted to WAI with VMAT. Renal function and survival rates were evaluated, and, for comparison purposes, similar VMAT and 3D‐CRT treatment plans were performed for WAI patients, and differences were dosimetrically evaluated regarding doses to the remaining kidney and other organs at risk and the planning target volume (PTV). Results After a median follow‐up time of 40.8 months (35.3‐52.2), no acute significant intestinal toxicity was observed, and median creatinine clearance was 110.1 and 103.3 mL/min/1.73 m², respectively, before treatment and at last follow‐up for WAI patients (P = 0.128). For comparative plans, maximum and median doses were lower for the remaining kidney with VMAT than with 3D‐CRT. VMAT was associated with better PTV coverage as compared with 3D‐CRT, with superior results for all the evaluated parameters (D95, D2, V100%, V98%, V95%; P = 0.018). Conclusion The use of VMAT technique is associated with lower radiation doses to the remaining kidney and better coverage to the PTV than 3D‐CRT technique for WAI, with preliminary clinical experience showing a favorable toxicity profile. Long‐term results from prospective studies might prove the ability of VMAT to spare renal function in the setting of WT treatment.

Pediatric radiotherapy for thoracic and abdominal targets: Organ motion, reported margin sizes, and delineation variations – A systematic review

“…CBCT, daily kV port films) during radiotherapy, of which 40 studies reported on applied margin sizes. Four studies reported that no IGRT was used [27][28][29][30], and in two studies IGRT techniques were not applicable as patients were not treated with radiotherapy [31,32]. In the remaining 65 studies the use of IGRT techniques during radiotherapy was not explicitly reported.…”

“…Most commonly reported margins types were GTV-CTV and CTV-PTV margins for thoracic [44, (Fig. 2A), abdominal [15,18,30,41,45,[50][51][52][53][54][55][56]60,[62][63][64]66,70,73,74,[76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94] (Fig. 2B), spinal [43,46,48,63,82, (Fig.…”

Harmonica consensus, controversies, and future directions in radiotherapy for pediatric Wilms tumors

“…29 Of note, successful births from autotransplanted ovarian tissue harvested from young pediatric female cancer patients have been reported. 30 Dosimetric analyses demonstrate OAR dose reduction for flank, 27 WART, 31 liver, 20 and WLI. 17 While benefit of IMRT/IMAT will take years to demonstrate, currently there is no consensus among radiation oncologists in COG and SIOP regarding target volume delineation and RT techniques for flank, WART and WLI.…”

“…Modulated RT, specifically IMRT and IMAT, has been shown to improve the therapeutic ratio for WT by focusing desired radiation dose to the tumor target and minimizing dose to adjacent OARs (Figure 2). Dosimetric analyses demonstrate OAR dose reduction for flank, 27 WART, 31 liver, 20 and WLI 17 . While benefit of IMRT/IMAT will take years to demonstrate, currently there is no consensus among radiation oncologists in COG and SIOP regarding target volume delineation and RT techniques for flank, WART and WLI 32 .…”

Towards Further Refinement of Radiotherapy Stratification in Children With Nephroblastoma

“…A guideline for translation of the target volumes of the conventional opposing photon beams into highly conformal volumes for flank irradiation has been added to the UMBRELLA SIOP-RTSG 2016 protocol [60]. Similarly, the application of modern techniques to whole-abdomen and whole-lung irradiation may contribute to a better adjacent heathy tissue protection [61,62].…”