Helical tomotherapy in the treatment of pediatric malignancies: a preliminary report of feasibility and acute toxicity

Abstract

BackgroundRadiation therapy plays a central role in the management of many childhood malignancies and Helical Tomotherapy (HT) provides potential to decrease toxicity by limiting the radiation dose to normal structures. The aim of this article was to report preliminary results of our clinical experience with HT in pediatric malignancies.MethodsIn this study 66 consecutive patients younger than 14 years old, treated with HT at our center between January 2006 and April 2010, have been included. We performed statistical analyses to assess the relationship between acute toxicity, graded according to the RTOG criteria, and several clinical and treatment characteristics such as a dose and irradiation volume.ResultsThe median age of patients was 5 years. The most common tumor sites were: central nervous system (57%), abdomen (17%) and thorax (6%). The most prevalent histological types were: medulloblastoma (16 patients), neuroblastoma (9 patients) and rhabdomyosarcoma (7 patients). A total of 52 patients were treated for primary disease and 14 patients were treated for recurrent tumors. The majority of the patients (72%) were previously treated with chemotherapy. The median prescribed dose was 51 Gy (range 10-70 Gy). In 81% of cases grade 1 or 2 acute toxicity was observed. There were 11 cases (16,6%) of grade 3 hematological toxicity, two cases of grade 3 skin toxicity and one case of grade 3 emesis. Nine patients (13,6%) had grade 4 hematological toxicity. There were no cases of grade 4 non-hematological toxicities. On the univariate analysis, total dose and craniospinal irradiation (24 cases) were significantly associated with severe toxicity (grade 3 or more), whereas age and chemotherapy were not. On the multivariate analysis, craniospinal irradiation was the only significant independent risk factor for grade 3-4 toxicity.ConclusionHT in pediatric population is feasible and safe treatment modality. It is characterized by an acceptable level of acute toxicity that we have seen in this highly selected pediatric patient cohort with clinical features of poor prognosis and/or aggressive therapy needed. Despite of a dosimetrical advantage of HT technique, an exhaustive analysis of long-term follow-up data is needed to assess late toxicity, especially in this potentially sensitive to radiation population.

A comparative study on the risks of radiogenic second cancers and cardiac mortality in a set of pediatric medulloblastoma patients treated with photon or proton craniospinal irradiation

“…The good agreement of RLAR values between Brodin et al [13] and the present work provided more strong evidence that a ratio of risks should be used for inter-institution comparisons. The second limitation is that we only investigated a passively scattered proton CSI and field-in-field photon CSI in this work, while other modalities like IMPT [13,34], IMRT [34,35], Tomotherapy [35,36] and Volumetric Modulated Arc Therapy (VMAT) [37] are also used at some centers. However, most of these advanced treatment modalities are not routinely used for CSI treatment, whereas the techniques in our study are.…”

Acute toxicity of craniospinal irradiation with volumetric‐modulated arc therapy in children with solid tumors

“…Despite the dosimetric advantages of VMAT and HT, practical implementation issues exist, including long treatment times. Recent HT studies have shown that highly conformal plans with excellent dose homogeneity with minimal increases in integral dose are achievable with reasonable treatment times . However, HT requires a specialized tomotherapy treatment unit, whereas VMAT can be performed with modern linear accelerators which are more readily available.…”

Prospective evaluation of multitarget treatment of pediatric patients with helical intensity-modulated radiotherapy

“…Nevertheless, there is a higher risk of developing second malignancies compared to adult patients, which may lead to a decrease in overall survival and quality of life after treatment [7][8][9]. In order to reduce side effects and long-term toxicity, intensity-modulated radiation therapy (IMRT) may constitute an adequate therapeutic approach.…”