The SIOP-Renal Tumour Study Group consensus statement on flank target volume delineation for highly conformal radiotherapy

Locoregional control using highly conformal flank target volumes and volumetric-modulated arc therapy in pediatric renal tumors: Results from the Dutch national cohort

“…To our knowledge, this is the first cohort of pediatric patients with a renal tumor that describes the locoregional outcome of highly conformal flank irradiation using new target volumes adjusted for postoperative organ shifts and optimized by the use of surgical clips and 4D-CT scans [17,21]. After a median followup of 3.1 years, two patients developed a locoregional relapse resulting in a 2-year LCR of 94%, which is in line with the reported number of locoregional events observed in patients with stage III WT treated by the use of a conventional technique within the SIOP-2001 and AREN0532 studies [4,25].…”

“…For target volume delineation, the lateral clip was used to determine the lateral tumor extension, while the superior clip was used to capture the intra-fraction motion of the tumor bed, as described in a previous report [21]. Gross Tumor Volumes (GTV) and Clinical Target Volumes (CTV) were corrected for the postoperative changes in anatomy, in line with the SIOP-RSTG consensus statement on highly conformal flank target volume delineation [17]. An Internal Target Volume (ITV) margin, defined as the maximum intra-fraction motion registered by the 4D-CTscan, was used to expand the CTV.…”

“…For decades, the use of two opposing Anterior-Posterior/Poster ior-Anterior (AP/PA) photon beams has been considered standard of care for flank RT, using the tumor volume before surgery as the target volume [16]. In the past years, the SIOP-RTSG has developed a new flank target volume definition that adjusts for the postoperative changes and intra-fraction motion [17]. Combined with modern RT techniques, this new target volume allows highly conformal dose distributions that reduce the risk of late toxicity to the surrounding healthy tissue [18][19][20].…”

“…Since November 2014, pediatric renal cancer care in The Netherlands has been centralized and all patients eligible for flank irradiation received Volumetric-Modulated Arc Therapy (VMAT) on highly conformal flank target volumes [17]. The aim of the current report was to describe the locoregional control and outcome after highly conformal flank irradiation and to evaluate whether recurrences might have been avoided by conventional RT by performing an in-depth dose reconstruction.…”

The contribution of surgical clips for optimizing highly-conformal image-guided flank irradiation in pediatric renal tumors: A single center experience

“…Radiotherapy (IGRT) techniques that allow high-precision dose delivery to complex target volumes. Prompted by this development, radiation oncologists affiliated to the SIOP-RTSG reached consensus on a highly-conformal target volume definition for flank irradiation: it was hypothesized that intraperitoneal tumor recurrence is unlikely in patients without major tumor rupture [7]. This was based on the fact that renal tumors are covered by a peritoneal lining and push aside, rather than invade, the intraperitoneal organs and abdominal wall.…”