Dataset Information

Long-term outcomes and prognostic factors of skull-base chondrosarcoma patients treated with pencil-beam scanning proton therapy at the Paul Scherrer Institute.

ABSTRACT: Skull-base chondrosarcoma (ChSa) is a rare disease, and the prognostication of this disease entity is ill defined.We assessed the long-term local control (LC) results, overall survival (OS), and prognostic factors of skull-base ChSa patients treated with pencil beam scanning proton therapy (PBS PT). Seventy-seven (male, 35; 46%) patients with histologically confirmed ChSa were treated at the Paul Scherrer Institute. Median age was 38.9 years (range, 10.2-70.0y). Median delivered dose was 70.0 GyRBE (range, 64.0-76.0 GyRBE). LC, OS, and toxicity-free survival (TFS) rates were calculated using the Kaplan Meier method.After a mean follow-up of 69.2 months (range, 4.6-190.8 mo), 6 local (7.8%) failures were observed, 2 of which were late failures. Five (6.5%) patients died. The actuarial 8-year LC and OS were 89.7% and 93.5%, respectively. Tumor volume > 25 cm(3) (P = .02), brainstem/optic apparatus compression at the time of PT (P = .04) and age >30 years (P = .08) were associated with lower rates of LC. High-grade (?3) radiation-induced toxicity was observed in 6 (7.8%) patients. The 8-year high-grade TFS was 90.8%. A higher rate of high-grade toxicity was observed for older patients (P = .073), those with larger tumor volume (P = .069), and those treated with 5 weekly fractions (P = .069).This is the largest PT series reporting the outcome of patients with low-grade ChSa of the skull base treated with PBS only. Our data indicate that protons are both safe and effective. Tumor volume, brainstem/optic apparatus compression, and age were prognosticators of local failures.

SUBMITTER: Weber DC

PROVIDER: S-EPMC4724177 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Long-term outcomes and prognostic factors of skull-base chondrosarcoma patients treated with pencil-beam scanning proton therapy at the Paul Scherrer Institute.

Weber Damien C DC Badiyan Shahed S Malyapa Robert R Albertini Francesca F Bolsi Alessandra A Lomax Antony J AJ Schneider Ralf R

Neuro-oncology 20150830 2

<h4>Background</h4>Skull-base chondrosarcoma (ChSa) is a rare disease, and the prognostication of this disease entity is ill defined.<h4>Methods</h4>We assessed the long-term local control (LC) results, overall survival (OS), and prognostic factors of skull-base ChSa patients treated with pencil beam scanning proton therapy (PBS PT). Seventy-seven (male, 35; 46%) patients with histologically confirmed ChSa were treated at the Paul Scherrer Institute. Median age was 38.9 years (range, 10.2-70.0y) ...[more]

PMID: 26323608

Similar Datasets

Project description:Proton therapy makes use of the favorable depth-dose distribution with its characteristic Bragg peak to spare normal tissue distal of the target volume. A steep dose gradient would be desired in lateral dimensions, too. The widespread spot scanning delivery technique is based, however, on pencil-beams with in-air spot full-widths-at-half-maximum of typically 1 cm or more. This hampers the sparing of organs-at-risk if small-scale structures adjacent to the target volume are concerned. The trimming of spot scanning fields with collimating apertures constitutes a simple measure to increase the transversal dose gradient. The current study describes the clinical implementation of brass apertures in conjunction with the pencil-beam scanning delivery mode at a horizontal, clinical treatment head based on commercial hardware and software components. Furthermore, clinical cases, which comprised craniopharyngiomas, re-irradiations and ocular tumors, were evaluated. The dosimetric benefits of 31 treatment plans using apertures were compared to the corresponding plans without aperture. Furthermore, an overview of the radiation protection aspects is given. Regarding the results, robust optimization considering range and setup uncertainties was combined with apertures. The treatment plan optimizations followed a single-field uniform dose or a restricted multi-field optimization approach. Robustness evaluation was expanded to account for possible deviations of the center of the pencil-beam delivery and the mechanical center of the aperture holder. Supplementary apertures improved the conformity index on average by 15.3%. The volume of the dose gradient surrounding the PTV (evaluated between 80 and 20% dose levels) was decreased on average by 17.6%. The mean dose of the hippocampi could be reduced on average by 2.9 GyRBE. In particular cases the apertures facilitated a sparing of an organ-at-risk, e.g. the eye lens or the brainstem. For six craniopharyngioma cases the inclusion of apertures led to a reduction of the mean dose of 1.5 GyRBE (13%) for the brain and 3.1 GyRBE (16%) for the hippocampi.

Project description:BackgroundAlthough pencil beam scanning (PBS) is the most conformal method for proton beam therapy (PBT) delivery, it is unknown if outcomes differ compared to treatment with passive scatter/uniform scanning (PS/US). This analysis compares patient reported outcomes (PRO) changes following PBS and PS/US for prostate cancer (PC) in a prospective multicenter registry study.MethodsWe evaluated PROs with the Expanded Prostate Cancer Index Composite (EPIC) instrument for men with localized PC enrolled in PCG 001-09 (NCT01255748). PROs were assessed at baseline and through 12 months of follow-up. We compared mean changes in EPIC scores, as well as the proportions of men experiencing a one- and two-fold minimally important difference (MID) in domain scores, between PBS and PS/US. Multivariate analyses (MVAs) were performed to further evaluate the association between proton modality and PRO changes.ResultsThree-hundred-and-four men completed EPIC at baseline; 72 received PBS and 232 received PS/US. The average quality-of-life (QOL) declines from baseline through 12 months did not significantly differ between the two groups. The proportion of men reporting a 1-MID decline at 12 months for PBS and PS/US was 34.3% and 27.4%, respectively, for urinary QOL (P = 0.27); 40. 1% and 40.9% for bowel QOL (P = 0.36); and 30. 1% and 36.6% for sexual QOL (P = 0.94). Corresponding 2-MID declines for PBS and PS/US were observed in 26.9% and 13.2% of men for urinary QOL (P = 0.01), 35.3% and 29.1% for bowel QOL (P = 0.33); and 16.4% and 18.1% for sexual QOL (P = 0.76). The association between proton modality and 2-MID changes in urinary QOL at 12-months remained significant on MVA (P = 0.007).ConclusionsThe results of this analysis show differences between PBS and PS/US with regards to two-fold MID changes in urinary function at 12 months, but no differences for average score declines over time. Future studies evaluating PRO measures between the two PBT modalities are warranted.

Dataset Information

Long-term outcomes and prognostic factors of skull-base chondrosarcoma patients treated with pencil-beam scanning proton therapy at the Paul Scherrer Institute.

Publications

Long-term outcomes and prognostic factors of skull-base chondrosarcoma patients treated with pencil-beam scanning proton therapy at the Paul Scherrer Institute.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets