Can We Spare the Pancreas and Other Abdominal Organs at Risk? A Comparison of Conformal Radiotherapy, Helical Tomotherapy and Proton Beam Therapy in Pediatric Irradiation

Abstract

ObjectivesLate abdominal irradiation toxicity during childhood included renal damage, hepatic toxicity and secondary diabetes mellitus. We compared the potential of conformal radiotherapy (CRT), helical tomotherapy (HT) and proton beam therapy (PBT) to spare the abdominal organs at risk (pancreas, kidneys and liver- OAR) in children undergoing abdominal irradiation.MethodsWe selected children with abdominal tumors who received more than 10 Gy to the abdomen. Treatment plans were calculated in order to keep the dose to abdominal OAR as low as possible while maintaining the same planned target volume (PTV) coverage. Dosimetric values were compared using the Wilcoxon signed-rank test.ResultsThe dose distribution of 20 clinical cases with a median age of 8 years (range 1–14) were calculated with different doses to the PTV: 5 medulloblastomas (36 Gy), 3 left-sided and 2 right-sided nephroblastomas (14.4 Gy to the tumor + 10.8 Gy boost to para-aortic lymphnodes), 1 left-sided and 4 right-sided or midline neuroblastomas (21 Gy) and 5 Hodgkin lymphomas (19.8 Gy to the para-aortic lymphnodes and spleen). HT significantly reduced the mean dose to the whole pancreas (WP), the pancreatic tail (PT) and to the ipsilateral kidney compared to CRT. PBT reduced the mean dose to the WP and PT compared to both CRT and HT especially in midline and right-sided tumors. PBT decreased the mean dose to the ispilateral kidney but also to the contralateral kidney and the liver compared to CRT. Low dose to normal tissue was similar or increased with HT whereas integral dose and the volume of normal tissue receiving at least 5 and 10 Gy were reduced with PBT compared to CRT and HT.ConclusionIn children undergoing abdominal irradiation therapy, proton beam therapy reduces the dose to abdominal OAR while sparing normal tissue by limiting low dose irradiation.

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

“…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.…”

Outcome of localized liver‐bile duct rhabdomyosarcoma according to local therapy: A report from the European Paediatric Soft‐Tissue Sarcoma Study Group (EpSSG)‐RMS 2005 study

“…Radiotherapy techniques have evolved during the duration of this study. Contemporary techniques such as image‐guided intensity modulated arc therapy and intensity modulated proton beam therapy deliver more conformal high‐dose volumes to abdominal tumors and are better able to spare nontarget tissues, which should in turn reduce the incidence and severity of late adverse effects. Furthermore, patients in this study were treated in the era before peer review of target volume definition and prospective radiotherapy quality assurance became standard practice.…”

Locoregional failure after postoperative flank irradiation for nephroblastoma: Results from the French cohort of the SIOP‐2001 trial

“…Several dosimetric studies showed the potential benefit of modern and highly conformal RT techniques with a restricted CTV, including helical tomotherapy, volumetric arc RT, and proton therapy. [7][8][9] In comparison to conventional RT, modern techniques could significantly reduce the mean dose to the liver (by 3%-72%), to the bowels (by 32%-41%), to the pancreas (by 28%-67%), and to the contralateral kidney (by 32%-61%). Reducing doses to healthy tissue may decrease the risk of acute and long-term toxicity, such as veno-occlusive disease, nausea, diabetes, or kidney failure, for example.…”

“…In this study, LRF were all located in the retroperitoneal tumor bed or lymph node region, thereby confirming that this area carries the highest risk of local relapse, and raising the issue of restricting the CTV to the retroperitoneum. Several dosimetric studies showed the potential benefit of modern and highly conformal RT techniques with a restricted CTV, including helical tomotherapy, volumetric arc RT, and proton therapy 7–9 . In comparison to conventional RT, modern techniques could significantly reduce the mean dose to the liver (by 3%–72%), to the bowels (by 32%–41%), to the pancreas (by 28%–67%), and to the contralateral kidney (by 32%–61%).…”