Overall survival and secondary malignant neoplasms in children receiving passively scattered proton or photon craniospinal irradiation for medulloblastoma

Abstract

BACKGROUND: Both intensity-modulated radiotherapy (RT) and passively scattered proton therapy have a risk of secondary malignant neoplasm (SMN) in children. To determine the influence of RT modality on the incidence of SMN after craniospinal irradiation (CSI), the authors compared the incidence of SMN in children who had medulloblastoma treated with either photon CSI plus an intensitymodulated RT boost (group I) or passively scattered proton CSI plus a boost (group II). METHODS: From 1996 to 2014, 115 children with medulloblastoma (group I, n = 63; group II, n = 52) received CSI followed by a boost to the tumor bed. Most patients had standard-risk disease (63.5%). The median follow-up was 12.8 years for group I and 8.7 years for group II. RESULTS: The 5-year and 10-year overall survival (OS) rates were 88.8% and 85.1%, respectively, for standard-risk patients and 63.1% and 57.3%, respectively, for high-risk patients, with no OS difference by RT modality (P = .81). Six SMNs were identified (4 in group I, 2 in group II). The 5-year and 10-year SMN incidence rates were 1.0% and 6.9%, respectively (0.0% and 8.0%, respectively, in group I; 2.2% and 4.9%, respectively, in group II; P = .74). Two SMNs occurred in the clinical target volume in the brain, 2 occurred in the exit dose region from the photon spinal field, 1 occurred in the entrance path of a proton beam, and 1 occurred outside the radiation field. There were no reported cases of secondary leukemia. CONCLUSIONS: This analysis demonstrates no difference in OS or SMN incidence between patients in groups I and II 10 years after RT.

Early outcome after craniospinal irradiation with pencil beam scanning proton therapy for children, adolescents and young adults with brain tumors

“…It is noteworthy that at 2 years, the reported actuarial freedom from G ≥ 3 toxicity was greater than 90% (Figure 2). These data compares favorably with previous studies [3][4][5][6][7][8]16 and supports the safety and efficacy of proton CSI for the control of CNS tumors.…”

“…Our 2year LC, DC, and OS rates of 86.3%, 80.5% and 84.7%, respectively, are consistent with recent reports investigating the use of CSI with protons among children and AYAs. [3][4][5][6][7][8] Of note, patients with recurrent or metastatic tumors at the start of PT were found to have a worse outcome. Our acute toxicity data, points to an adequate tolerance of the treatment.…”

“…2 Clinical outcomes among patients with medulloblastoma receiving CSI with protons have shown similar progression-free survival rates to conventional photon radiotherapy while presenting acceptable toxicity. [3][4][5][6] Likewise, retrospective studies of adolescents and young adults (AYAs) treated with proton CSI have also reported promising results in terms of toxicity and tumor control rates. 7,8 The role of PBSPT for other histologies that may require CSI has been less investigated.…”

Radiotherapy in Medulloblastoma—Evolution of Treatment, Current Concepts and Future Perspectives

“…In a retrospective series, 115 children with medulloblastoma received photon CSI ( n = 63, group 1) or proton CSI ( n = 52, group 2) followed by a boost to the tumor bed. The 5-year and 10-year secondary tumor incidence rates were 0.0% and 8.0%, respectively, in group 1; and 2.2% and 4.9%, respectively, in group 2; p = 0.74) [ 61 ]. However, data of larger controlled prospective clinical trials with long-term follow-up is needed to validate the findings on this important issue.…”

Adult Medulloblastoma: Updates on Current Management and Future Perspectives

“…However, apart from estimations from plan comparisons, clinical evidence concerning this field is still sparse. In a retrospective series of 115 children with MB after photon CSI or proton CSI, the secondary tumor incidence rates were not different between the two groups [ 121 ]. Prospective data from controlled clinical trials on toxicity and secondary cancers are sparse but needed in adults with MB.…”