The NIH pediatric/young adult chordoma clinic and natural history study: Making advances in a very rare tumor

BACKGROUND

Chordomas are rare tumors arising from the skull base and spine, with approximately 20 pediatric chordoma cases in the Unitedn States per year. The natural history and optimal treatment of pediatric chordomas, especially poorly differentiated and dedifferentiated subtypes, is incompletely understood. Herein, we present findings from our first National Cancer Institute (NCI) chordoma clinic and a retrospective analysis of published cases of pediatric poorly differentiated chordomas (PDC) and dedifferentiated chordomas (DC).

METHODS

Patients less than 40 years old with chordoma were enrolled on the NCI Natural History and Biospecimens Acquisitions Study for Children and Adults with Rare Solid Tumors protocol (NCT03739827). Chordoma experts reviewed patient records, evaluated patients, and provided treatment recommendations. Patient-reported outcomes, biospecimens, and volumetric tumor analyses were collected. A literature review for pediatric PDC and DC was conducted.

RESULTS

Twelve patients (median age: 14 years) attended the clinic, including four patients with active disease and three patients with PDC responsive to systemic therapy. Consensus treatment, management, and recommendations were provided to patients. Literature review returned 45 pediatric cases of PDC or DC with variable treatments and outcomes.

CONCLUSIONS

A multidisciplinary expert clinic was feasible and successful in improving understanding of pediatric chordoma. While multimodal approaches have all been employed, treatment for PDC has been inconsistent and a recommended standardized treatment approach has not been defined. Centralized efforts, inclusive of specialized chordoma-focused clinics, natural history studies, and prospective analyses will help in the standardization of care for this challenging disease.

Clinical outcomes of head and neck adenoid cystic carcinoma patients treated with pencil beam-scanning proton therapy

OBJECTIVE

The aim of this study was to evaluate the outcome of patients with head and neck adenoid cystic carcinoma (ACC) treated using pencil beam scanning proton therapy (PBS PT) at our institution.

MATERIALS AND METHODS

Thirty-five patients who underwent treatment with PBS PT for ACC between 2001 and 2017 were included. Local control (LC), distant control (DC), progression-free survival (PFS), overall survival (OS) and their prognostic factors were evaluated. Adverse effects were prospectively assessed.

RESULTS

The median patient follow-up was 30 months. Prior to PT, 26 patients (74.3%) underwent surgery with R0/R1/R2 outcome in 5, 13 and 8 cases, respectively. Nine patients (25.7%) presented with inoperable disease. The 2-year LC, DC, PFS and OS was 92.2%, 77.8%, 74.3% and 88.8%, respectively. LC was influenced by patient age (p = 0.002) with a significant difference between local and distant failure (median 61.3 vs. 42.3 years, p = 0.005). Tumor T stage was a significant risk factor for PFS (p = 0.045) and tumor prognostic group affected OS (p = 0.049). No significant survival advantage for operable vs. inoperable disease could be identified. The acute and late grade 3 toxicity rates were 14.3% and 6.1%, respectively. No acute or late grade 4/5 toxicities were observed.

CONCLUSIONS

PBS PT is an effective and safe treatment for patients with head & neck ACC in both definitive and adjuvant setting. Distant metastases are the main pattern of failure. Age, tumor stage and clinical stage had a significant negative impact on LC, OS and PFS.

Defining Clinical Indications of Proton Beam Therapy at National Level in the Kingdom of Saudi Arabia

The Saudi Particle Therapy Centre (SPTC) is establishing proton beam therapy (PBT) services within Kingdom of Saudi Arabia (KSA). Thus, national guidelines for the pertinent draft, and recommendations of PBT for cancer patients are utmost important. Saudi Particle Therapy Centre invited a panel of expert radiation oncologists practicing within KSA to formulate national clinical practice guidelines for the referral, absolute and relative indications and dose/fractionation for PBT. After identifying the key clinical questions, ample search through PubMed, EMBASE, and various search drives was accomplished for appropriate meta-analyses, clinical trials, case-control, and case series studies, and case reports. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach was incorporated to formulate various recommendations. Saudi Particle Therapy Centre expert panel recommended PBT as utter modality for ocular tumors, base of skull/spine tumors, hepatocellular carcinoma, all pediatric central nervous system (CNS) malignancies, para-nasal sinuses/nasal cavity tumors and for re-irradiation of all sites aimed for cure. However, PBT may be contemplated, as a relative indication if no other parallel option is available, or when photon therapy plans exceed the dose constraints for critical structures. Further, panel did not recommend routine PBT for other sites beyond clinical trials. However, individual oncology patients can be considered for PBT after a multidisciplinary approach and expert’s opinion.

Excellent Pathologic Response and Atypical Clinical Course of High-Grade Extremity Sarcoma to Neoadjuvant Pencil Beam Scanning Proton Therapy

Neoadjuvant radiation therapy, followed by definitive surgical resection, remains the standard of care for resectable high-grade and unresectable soft tissue sarcomas. Proton therapy offers the promise of highly conformal dose distributions with improved sparing of neighboring normal tissues as compared with conformal and intensity modulated photon techniques. It is unclear whether proton therapy may offer an improved tumoral response, especially with dose escalation, in this relatively radio-insensitive tumor type. We, herein, present a patient with an excellent pathologic response to preoperative pencil beam scanning proton therapy despite a complex treatment course.

Dramatic Response of a Large Sacral Chordoma to Intensity Modulated Proton Beam Therapy

Sacral chordomas are slow-growing, indolent, and locally invasive tumors that typically present with pain and neurologic dysfunction. Wide en-bloc surgical excision is the primary treatment, but achieving adequate margins is difficult and surgery is often associated with significant morbidity. Adjuvant radiation therapy (RT) is utilized to decrease the risk of local recurrence or as definitive treatment for nonsurgical candidates. Although chordomas are considered to be relatively radioresistant tumors, several studies have demonstrated tumor response to high-dose proton therapy. Here, we present a patient with a large sacral chordoma who underwent definitive treatment with intensity-modulated proton therapy (IMPT).

Tumour control and Quality of Life in children with rhabdomyosarcoma treated with pencil beam scanning proton therapy

PURPOSE

To assess clinical outcomes in children with rhabdomyosarcoma (RMS) treated with pencil beam scanning (PBS) proton therapy (PT).

METHODS AND MATERIALS

Eighty-three RMS (embryonal, n=74; 89%) patients treated between January 2000 and December 2014 were included. The median age was 4.5years (range, 0.8-15.5). All patients received systemic chemotherapy according to prospective protocols. Patients had low-, intermediate-, and high-risk disease in 24%, 63%, and 13% of cases, respectively. The median total dose delivered was 54Gy(RBE) (range, 41.4-64.8).

RESULTS

After a median follow-up time of 55.5 months (range, 0.9-126.3), local failure occurred in 16 patients. The 5-year local-control survival rate was 78.5% [95% confidence interval (CI), 69.5-88.5%]. Significant predictors for local failure were group/stage, tumour location, and size. Fourteen patients (16%) died, all from tumour progression. The 5-year overall survival was 80.6% (95%CI, 71.8-90.0%). The 5-year incidence of grade 3 non-ocular late toxicity was 3.6% (95%CI, 1-12%). No grade 4-5 late toxicities were observed. One radiation-induced malignancy was observed (1.2%). The Quality of Life (QoL) scores increased significantly after PT compared to baseline values.

CONCLUSIONS

PBS PT led to excellent outcome in children with RMS. Late non-ocular toxicity was minimal and QoL good.

Long term outcomes of patients with skull-base low-grade chondrosarcoma and chordoma patients treated with pencil beam scanning proton therapy

PURPOSE

To evaluate the long term tumor control and toxicity of skull base tumors treated with pencil beam scanning proton therapy (PT).

MATERIALS AND METHODS

PT was delivered to 151 (68%) and 71 (32%) chordoma and chondrosarcoma (ChSa) patients, respectively. Mean age of patients was 40.8±18.4years and the male to female ratio was 0.53. The postoperative tumor was abutting the brainstem or optic apparatus in 71 (32.0%) patients. The postoperative mean gross tumor volume (GTV) was 35.7±29.1cm(3). The delivered mean PT dose was 72.5±2.2GyRBE.

RESULTS

After a mean follow-up of 50 (range, 4-176) months, 35 local (15.8%) failures were observed between 10.9 and 85.4months. The estimated 7-year LC rate for chordoma (70.9%; CI95% 61.5-81.8) was significantly lower compared to the LC rate for ChSa patients (93.6%; 95%CI 87.8-99.9; P=0.014). The estimated 7-year distant metastasis-free- and overall survival rate was 91.6% (95%CI 91.6-98.6) and 81.7% (95%CI 74.7-89.5), respectively. On multivariate analysis, optic apparatus and/or brainstem compression, histology and GTV were independent prognostic factors for LC and OS. The 7-year high grade toxicity-free survival was 87.2 (95%CI 82.4-92.3).

CONCLUSIONS

PBS PT is an effective treatment for skull base tumors with acceptable late toxicity. Optic apparatus and/or brainstem compression, histology and GTV allow independent prediction of the risk of local failure and death in skull base tumor patients.

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

BACKGROUND

Skull-base chondrosarcoma (ChSa) is a rare disease, and the prognostication of this disease entity is ill defined.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Differential sensitivity of choroidal endothelial, retinal ganglion, and retinal pigment epithelial cells in vitro to proton radiation

PURPOSE

To evaluate the differential sensitivity of choroidal endothelial, retinal pigment epithelial, and retinal ganglion cells to escalating doses of proton beam radiation and to establish a safe dose range for the management of choroidal neovascularization associated with age-related macular degeneration (AMD).

DESIGN

Laboratory investigation.

METHODS

Proliferating simian choroidal endothelial cells (RF/6A), differentiated rat retinal ganglion cells (RGC-5), and serum-starved human retinal pigment epithelial cells (ARPE-19) were exposed to 2, 4, 8, and 12 cobalt gray equivalent of proton beam radiation and cell viability was quantified on day 9. Reactive oxygen species levels were analyzed.

RESULTS

Significant decline of choroidal endothelial cell viability was noted as dose escalated from 4 to 8 cobalt gray equivalent with maximum effect observed at 12 cobalt gray equivalent. RGC-5 and ARPE-19 cell count decreased to 95% and 62.7% at 8 cobalt gray equivalent, respectively. Sub-analysis between 4 and 8 cobalt gray equivalent radiation revealed significant decrease in choroidal endothelial cell viability (43.1% at 7 cobalt gray equivalent and 32.3% at 8 cobalt gray equivalent of radiation). Correspondingly, RGC-5 and ARPE-19 cells did not show decrease in cell count or viability. Reactive oxygen species levels significantly increased in radiation-treated choroidal endothelial cells (8.3%-11.9%).

CONCLUSIONS

At 6-8 cobalt gray equivalent proton beam radiation, retinal ganglion and retinal pigment epithelial cells are preserved while choroidal endothelial cells are completely inhibited. This dosage offers optimum therapeutic safety window for treatment using proton beam radiation for exudative AMD.

Response to sunitinib in combination with proton beam radiation in a patient with chondrosarcoma: a case report

Introduction

Chondrosarcoma is well-known to be primarily resistant to conventional radiation and chemotherapy.

Case presentation

We present the case of a 32-year-old Caucasian man with clear cell chondrosarcoma who presented with symptomatic recurrence in his pelvis and metastases to his skull and lungs. Our patient underwent systemic therapy with sunitinib and then consolidation with proton beam radiation to his symptomatic site. He achieved complete symptomatic relief with a significantly improved performance status and had an almost complete and durable metabolic response on fluorine-18-fluorodeoxyglucose positron emission tomography.

Conclusions

Our findings have important clinical implications and suggest novel clinical trials for this difficult to treat disease.

Evaluation of proton beam radiation sensitivity of proliferating choroidal endothelial and retinal ganglion cells with clonogenic assay

CONTEXT

Proton beam therapy offers the advantage of precise delivery with limited damage to the healthy tissue and is being tested in the management of exudative age-related macular degeneration (AMD). However, the dosages tested are empirical and not based on preclinical studies.

OBJECTIVE

In this study we evaluated the effects of varying doses of proton beam radiation on choroidal endothelial cells (CECs) and retinal ganglion cells (RGCs) using clonogenic assay to determine differential sensitivity.

MATERIALS AND METHODS

Each cell type has different efficiency to replicate (plating efficiency (PE)). PE of CEC (RF/6A) and RGC (RGC-5) grown in culture flasks was determined by plating 250 cells each (without any treatment) and counting the number of colonies after 13 days. Radiation induced sensitivity was determined by exposing the semi-confluent RF/6A and RGC-5 cells to proton beam at the doses of 0 (control), 2, 4, 8 and 12 cobalt gray equivalent (CGE). The ability of the cells to repair and replicate to form colonies were analyzed 13 days after radiation with crystal violet stain and the survival ratio was calculated. The significance of survival was analyzed using ANOVA (Graphpad Instat.3).

RESULTS

The PE of CEC and RGC was 12.96 ± 0.29% and 40.7 ± 1.48%, respectively. A survival ratio of CEC at 2, 4, 8 and 12 CGE proton radiation was 66.0 ± 8.6%, 44.3 ± 6.5%, 7.6 ± 0.3% and 1.14 ± 0.06% on exposure to 2, 4, 8 and 12 CGE proton radiation, respectively, p < 0.01). Survival ratio of RGC was 71.1 ± 22.4% (p = 0.05), 40.2 ± 7.9%, 8.89 ± 2.6% and 0.78 ± 0.31% at 2, 4, 8 and 12 CGE dosages (p < 0.001).

DISCUSSION

CEC showed dose-dependent decrease in survival rate with values attaining significance at all radiation dosages. In contrast, RGC was comparatively radio resistant and were able to replicate at lower doses and sensitive at higher doses after proton beam radiation.

CONCLUSION

Since CECs proliferate during neovascularization, this clonogenic assay is a useful assay to assess the sensitivity of CEC to radiation. This study identified that CEC were more sensitive to proton beam radiation than RGC at all doses. This may provide a therapeutic window for administration of proton beam radiation in the management of AMD.

Reduce in variation and improve efficiency of target volume delineation by a computer-assisted system using a deformable image registration approach

PURPOSE

To determine whether a computer-assisted target volume delineation (CAT) system using a deformable image registration approach can reduce the variation of target delineation among physicians with different head and neck (HN) IMRT experiences and reduce the time spent on the contouring process.

MATERIALS AND METHODS

We developed a deformable image registration method for mapping contours from a template case to a patient case with a similar tumor manifestation but different body configuration. Eight radiation oncologists with varying levels of clinical experience in HN IMRT performed target delineation on two HN cases, one with base-of-tongue (BOT) cancer and another with nasopharyngeal cancer (NPC), by first contouring from scratch and then by modifying the contours deformed by the CAT system. The gross target volumes were provided. Regions of interest for comparison included the clinical target volumes (CTVs) and normal organs. The volumetric and geometric variation of these regions of interest and the time spent on contouring were analyzed.

RESULTS

We found that the variation in delineating CTVs from scratch among the physicians was significant, and that using the CAT system reduced volumetric variation and improved geometric consistency in both BOT and NPC cases. The average timesaving when using the CAT system was 26% to 29% for more experienced physicians and 38% to 47% for the less experienced ones.

CONCLUSIONS

A computer-assisted target volume delineation approach, using a deformable image-registration method with template contours, was able to reduce the variation among physicians with different experiences in HN IMRT while saving contouring time.

Functional imaging in treatment planning in radiation therapy: a review

The remarkable technical developments obtained in radiation oncology have resulted in an increasing use of image-based treatment planning in radiation therapy for three-dimensional and intensity modulated radiation therapy, stereotactic irradiation and image-guided brachytherapy. There has been increased use of computer-based record and verify systems as well as electronic portal imaging to enhance treatment delivery. From the data presented it is evident that PET scanning and other functional imaging techniques play a major role in the definition of tumor extent and staging of patients with cancer. The recent introduction of a combined CT and PET scanner will substantially simplify image acquisition and treatment planning.

The human Hsp70B gene at the HSPA7 locus of chromosome 1 is transcribed but non-functional

The human heat-inducible Hsp70B and Hsp70B' genes were co-localized to 1q23.1 by in situ hybridization. However, though transcripts from Hsp70B could be detected in heat-shocked cells, DNA sequence analyses of both the gene and cDNA copies of the mRNA indicate the gene is non-functional. Moreover, mouse homologues of Hsp70B/B' were not detected by Southern blot analysis, suggesting Hsp70B/B' arose from either Hsp70-1or Hsp70-2 after the divergence of mice and humans.