Stereotactic Body Radiotherapy (SBRT) for Breast Cancer Spinal Metastases is Associated with Low Rates of Long-Term Local Failure (LF) and Vertebral Compression Fracture (VCF) Independent of Molecular Status

PURPOSE/OBJECTIVE(S)

There is limited outcome data specific to breast cancer spinal metastases following spine SBRT. This study aims to report outcomes specific to breast cancer spinal metastases receiving spine SBRT and determine the implication of biomarker status.

MATERIALS/METHODS

We have been maintaining a prospective database since the inception of the spine SBRT program. A retrospective review identified 168 breast cancer patients with 409 spinal segments treated with spine SBRT between January 2008 and January 2023. Molecular subtypes were grouped based on luminal A, luminal B, basal, and HER2 enriched. Patients were followed with q3-monthly full-spine MRI and a clinical assessment. The primary endpoint was MRI-based local failure (LF), and secondary endpoints were overall survival (OS) and vertebral compression fracture (VCF).

RESULTS

The median follow-up was 33 months (range, 3.3-123 months). Amongst the 168 patients, the majority were ECOG 0 or 1 (95%), neurologically intact (94%), polymetastatic (74%), and either luminal A (71%) or luminal B (8%). A total of 17% of patients were HER2+ve versus 83% HER2-ve. Of 409 treated segments the majority (76%) had no prior radiation or surgery (de novo), were SINS stable (60%), had either no or low-grade epidural disease (86%) and treated with 24-28 Gy in 2 fractions (73%). The LF and OS rates at 1, 3, and 5 years were 5%, 11%, and 14%, respectively, and 91%, 65%, and 45%, respectively, independent of molecular subtype on univariate analyses. The cumulative risk of VCF at 2 and 5 years was 7% and 10%, respectively.

CONCLUSION

We observe, in the largest breast cancer spine cohort to date, excellent long-term local control rates independent of molecular sub-group, and acceptable VCF rates.

Outcomes Specific to Spinal Metastases with Paraspinal Disease Extension Following Spine Stereotactic Body Radiotherapy

PURPOSE/OBJECTIVE(S)

Spinal metastases with paraspinal disease (PD) extension are known to have worse outcomes following stereotactic body radiotherapy (SBRT). Characteristics of the PD itself have not been investigated to determine the impact on outcomes such as local control, which is the purpose of this study.

MATERIALS/METHODS

We retrospectively reviewed those patients who had SBRT for spinal metastases with PD disease, identified from a prospectively maintained database. Spinal metastases previously irradiated or surgical resected were excluded. The extent of PD was classified as involving the rib, neuroforamina, and muscle invasion. The gross tumor volume of PD (GTV_PD) and the clinical target volume of PD (CTV_PD) were segregated from the bony compartments based on the treatment plan contours. The outcomes of interest included the cumulative risk of local failure (LF), re-irradiation rates (ReRT), and overall survival (OS). LF and ReRT were estimated for each treated sites using the competing risk model (death as the competing risk), while OS was evaluated per patient using the Kaplan Meier method.

RESULTS

A total of 86 patients with 96 spinal metastases sites with PD were included. Of the 96 treated sites, 65% (62/96), 29% (28/96) and 6% (6/96) of PD spanned 1, 2, and 3 vertebral levels respectively. The median follow-up was 12.4months (range: 0.6-100months). The 6- and 12-month OS for the cohort was 81% and 51%, respectively. 33/86 (38%) patients had radioresistant cancer (gastrointestinal, renal cell carcinoma, thyroid, sarcoma, or melanoma). Involvement of rib, neuroforamina and muscle invasion were observed in 39% (37/96), 65% (62/96) and 21% (20/96) of the treated sites, respectively. Epidural disease was present in 57% (55/96) of treated sites. The median GTV_PD volume was 7cc (range: 0.3-114cc), and the median CTV_PD volume was 24cc (range: 0.4-248cc). The prescribed doses were 24 Gy/2 fractions (fx) (80%), 28 Gy/2 fx (10%) and 30 Gy/4 fx (10%). There were 84 treated sites with at least one post-treatment MRI available for LF assessment. The crude LF risk was 32% (27/84), and the 6- and 12-month cumulative LF rates were 12% and 28%, respectively. There was a trend towards an increased risk of LF when PD involved the rib (35% vs 24% at 1 year respectively, P = 0.07) and muscle (67% vs 20% at 1 year respectively; P = 0.06), but no difference in LF for neuroforamina involvement (26% vs 34% at 1 year respectively, P = 0.5). There were no differences in LF based on cancer radioresistance (P = 0.6), GTV_PD volume (P = 0.3) or CTV_PD volume (P = 0.4). Of the 96 treated sites, 14% (14/96) were re-irradiated (9 with repeat SBRT and 5 with conventional EBRT) at a median of 15 months (range: 4.7-59 months) post initial SBRT. The cumulative incidence of ReRT at 6- and 12-months were 1.2% and 7.3%, respectively.

CONCLUSION

PD involving adjacent rib and muscle may be associated with worse LF following SBRT. Further expansion of the cohort and dosimetric analyses are ongoing.

Stereotactic Body Radiotherapy for Posterior Element Only Spinal Metastases: Outcomes and Validation of Recommended Clinical Target Volume Delineation Practice

PURPOSE/OBJECTIVE(S)

Spine stereotactic body radiotherapy (SBRT) results in improved local control and pain response compared to conventional external beam radiotherapy. Consensus stipulates MRI-based delineation of the clinical target volume (CTV) is critical and is based on spine segment sector involvement. The applicability of these contouring guidelines to metastases confined to the posterior elements is unknown. The purpose of this study was to determine the patterns of failure, as well as the safety of treating posterior element metastases when the vertebral body was intentionally excluded from the CTV.

MATERIALS/METHODS

A retrospective review of a prospectively maintained database of 605 patients and 1412 spine segments treated with spine SBRT was performed. Only treated segments involving the posterior elements alone were included for the analyses. The primary outcome was local failure, as per SPINO recommendations, and secondary outcomes included patterns of failure, toxicities. Clinical and tumor factors were reported with descriptive statistics. The cumulative risk of local failure was estimated using the Fine-Gray method, accounting for death before local failure as a competing risk.

RESULTS

A total of 24/605 patients and 31/1412 segments within the database were treated to the posterior elements only. Local failure occurred in 11/31 segments. The cumulative rate of local recurrence was 9.7% at 12 months and 30.8% at 24 months. Amongst local failures, the most common histologies were renal cell carcinoma (36.4%) and non-small cell lung cancer (36.4%). At baseline, 4/11 (36.4%) segments with local failure (36.4%) had epidural disease and 8/11 (72.7%) had paraspinal disease. Most local failures were treated in the de novo setting (8/11, 72.7%). 6/11 (54.5%) failed exclusively within treated CTV sectors and 5/11 (45.5%) with both treated and adjacent untreated sectors. Of these five, four had disease progression within the untreated vertebral body. No failures occurred exclusively within the untreated vertebral body. One patient (4.2%) experienced a grade 4 skin toxicity and one patient (4.2%) developed an iatrogenic Grade 1 vertebral compression fracture.

CONCLUSION

Posterior element alone metastases are rare. Our analyses support SBRT consensus contouring guidelines such that the vertebral body can be excluded from CTV in spinal metastases confined to the posterior elements.

Outcomes Following Dose Escalated Radiotherapy for High Grade Meningioma

PURPOSE/OBJECTIVE(S)

Conventionally fractionated radiotherapy (RT) is a defined treatment following surgery for atypical and malignant meningioma. However, the optimal radiotherapeutic approach is not well defined. We present the results of our dose-escalation strategy.

MATERIALS/METHODS

Consecutive patients with a histopathologic grade 2 or 3 meningioma treated with RT were retrospectively reviewed. The primary outcome was progression-free survival (PFS), and secondary outcomes included cause-specific survival (CSS), overall survival (OS), local failure and incidence of radiation necrosis. We specifically compared the dose-escalation cohort, defined as those treated with ≥66 Gy EQD2 (equivalent dose in 2 Gy fractions, a/b = 10), to the standard dose cohort receiving <66 Gy EQD2. We defined adjuvant as RT delivered within 6 months of surgery otherwise the treatment was salvage.

RESULTS

A total of 118 patients with Grade 2 (111/118) or 3 (7/118) meningioma were identified. 54/118 (45.8%) received dose-escalation and 64/118 (54.2%) standard dosing. 34/54 (63.0%) dose-escalated and 45/64 (70.3%) standardly dosed were treated adjuvantly. The median follow-up was 45.4 months (IQR: 24.0-80.0 months) and median OS was 9.7 years. Post-operative residual disease was present in all dose-escalated patients, as compared to 65.6% in the standard dose cohort. PFS at 3-, 4- and 5-years in the dose-escalated vs. standard dose cohort were 78.9%, 72.2% and 64.6% vs. 57.2%, 49.1% and 40.8%, respectively, (p = 0.030). On multivariable (MVA) analysis, dose-escalation (HR: 0.544, 95% CI: 0.303-0.977, p = 0.042) was associated with improved PFS, whereas ≥2 surgeries (HR: 1.989, 95% CI: 1.049-3.773, p = 0.035) and older age (HR: 1.035, 95% CI:1.015-1.056, p<0.001) associated with worse PFS. The cumulative risk of local failure at 3-, 4- and 5-years in the dose-escalated vs. standard dose cohort were 16.9%, 23.8% and 31.8% vs. 39.6%, 45.6% and 53.9%, respectively, favoring dose-escalation (p = 0.016). MVA confirmed dose-escalation as predictive of a lower risk of LF (HR: 0.483, 95% CI: 0.263-0.887, p = 0.019), while ≥2 surgeries prior to RT predicted for greater LF rates (HR:2.145, 95% CI:1.220-3.771, p = 0.008). A trend was observed for prolonged CSS and OS in the dose escalation cohort (p = <0.1). Seven patients (5.9%) developed symptomatic radiation necrosis (RN) with no significant difference between the two cohorts.

CONCLUSION

Dose-escalated radiotherapy for high grade meningioma to at least 66 Gy is associated with significantly improved rates of local control and PFS with an acceptable risk of RN.

Staged Stereotactic Radiosurgery as a Novel Adaptive Approach to Salvage Previously Irradiated Brain Metastases

PURPOSE/OBJECTIVE(S)

We report outcomes specific to a novel 3 fraction (frx) staged stereotactic radiosurgery (St-SRS) regimen designed to salvage metastases previously irradiated and considered to be at high risk of radiation necrosis (RN).

MATERIALS/METHODS

A total of 24 patients with 55 metastases treated with our 3 frx St-SRS approach were reviewed. Prior to each frx, patients were re-simulated and planned with a new MRI to allow for treatment adaption. The primary endpoint was the cumulative incidence of local failure (LF) and secondary endpoints included tumor dynamics and RN rates.

RESULTS

The median follow up was 9.0 months (range: 2.7-40.1 months) and median age was 59-years (range: 32-84). Primary cancers were of breast (44%), lung (33%), melanoma (22%), and gastro-intestinal (1%) origin. Individual metastases treated with St-SRS had initially failed surgery and post-op cavity hypofractionated SRS (HSRS) for 2/55 (4%), SRS alone for 19/55 (34%), whole brain radiation (WBRT) alone for 6/55 (11%), HSRS for 2/55 (4%), and prior SRS and WBRT exposure for 28/55 (51%). 46/55 (84%) were prescribed 8 Gy, 8 Gy, 4 Gy; 8/55 (14%) had 6 Gy, 6 Gy, 4 Gy and 1/55 (2%) had 8 Gy, 8 Gy, 6 Gy. The median number of weeks between frx was 2.6 (range: 1.0-6.8). The median of the mean and maximum target doses were 9.7 Gy (range: 5.4-11.7 Gy) and 12.4 Gy (range, 7.5-16.0 Gy) respectively. The median prescription isodose line was 62% (range: 50-85%). The mean lesion volume and diameter was 3.8cc (range: 0.05-24.8cc) and 1.6cm (range: 0.2-4.4cm), respectively. The mean percent target volume coverage, Paddick Conformality Index and Gradient Index were 100% (range: 97-100%), 0.7 (range: 0.1-0.9), and 3.2 (range: 2.5-6.7), respectively. The mean volume change between staged frxs was -4.2% (range: -69.3 to +63.1%), and based on the first and last St-SRS MRI was -10.8% (range: -86.6% to +68.7%). The crude LF rate was 27%. The median time to LF was 3.4 months (range: 1.2-7.4 months). Amongst those with a LF, 7/15 (46%) were melanoma, 6/15 (40%) HER2 positive breast cancer, 1/15 (7%) gastrointestinal and 1/15 (7%) non-small cell lung carcinoma. 8/15 (53%) had prior WBRT and SRS exposure, 1/16 (7%) surgery and cavity HSRS, 5/15 (33%) SRS alone and 1/15 (7%) WBRT alone. Only asymptomatic RN events were observed in 4/55 (7%).

CONCLUSION

St-SRS is a promising approach to salvage previously irradiated brain metastases, including prior SRS, with a favorable rate of RN. Tumor volume dynamics between stages can be significant warranting adaptive replanning.

Multi-Institutional Validation of the Recursive Partitioning Analysis for Overall Survival in Patients Undergoing Spine Radiosurgery for Spine Metastasis

PURPOSE/OBJECTIVE(S)

The recently published spine radiosurgery (sSRS) recursive partitioning analysis (RPA) for overall survival (OS) separated patients into 3 distinct prognostic groups. We sought to externally validate this RPA using 3 separate multi-institutional datasets.

MATERIALS/METHODS

A total of 444 patients were utilized to develop the recently published sSRS RPA predictive of OS in patients with spine metastases. The RPA identified three distinct prognostic classes. RPA Class 1 was defined as KPS >70 and controlled systemic disease (n = 142); RPA Class 2 was defined as KPS>70 with uncontrolled systemic disease or KPS ≤70, age ≥54 and absence of visceral metastases (n = 207); RPA Class 3 was defined as KPS ≤70 and age <54 years or KPS≤70, age ≥54 years and presence of visceral metastases (n = 95). We utilized data from 3 large tertiary care centers to independently validate this RPA. Data from each institution was utilized independently to validate the RPA to minimize confounding based on institutional differences in patient selection. A total of 1,184 patients (221 patients from institution A, 749 institution B, and 214 from institution C) were in the validation cohort and were divided based on their RPA Class. Kaplan-Meier method was used to estimate OS and log-rank test was used to compare OS between RPA classes.

RESULTS

In each of the validation cohorts, the median OS was 19.9 months (institution A), 11.0 months (institution B), and 24.4 months (institution C). The patient distribution into RPA classification based on Institution A/B/C was, Class 1 (19.4%, 15.1%, 50.5%), Class 2 (74.7%, 57.7%%, 37.9%), and Class 3 (5.9%, 27.2%%, 11.2%), respectively. The median OS for patients in the validation cohort at Institution A/B/C based on RPA class was Class 1 (54 months, 27.1 months, 50.0 months), Class 2 (15.9 months, 13.0 months, 15.1 months) and Class 3 (6.9 months, 3.5 months, 6.1 months), respectively. Patients in RPA Class 1 had a significantly better OS compared to those in Class 2 of the each of the three external institution validation cohorts (p<0.01). Similarly, patients in RPA Class 2 had a significantly better OS compared to those in Class 3 (p<0.01).

CONCLUSION

The external datasets from three large institutions independently validated the spine SRS RPA successfully for OS in patients undergoing sSRS for spinal metastases. This is the first RPA for OS to have been externally validated using multiple large datasets. Based on this validation, upfront spine SRS is strongly supported for patients in RPA Class 1 and Class 2 and is also cost effective with median OS >11 months for these patients. Patients in RPA Class 3 would benefit most from upfront conventional radiotherapy given their poor expected survival. Given successful external validation, this RPA helps guide physicians to identify those patients with spinal metastases who most benefit from sSRS.

Molecular Status Predicts for Local Control in Patients with Non-Small Cell Lung Cancer Spinal Metastases Following Spine Stereotactic Body Radiotherapy

PURPOSE/OBJECTIVE(S)

We report outcomes after spine stereotactic body radiotherapy (SBRT) in patients with metastatic non-small cell lung cancer (NSCLC), to determine the significance of programmed death-ligand 1 (PD-L1) status and epidermal growth factor (EGFR) mutation on local failure (LF) rate.

MATERIALS/METHODS

A total of 165 patients and 389 spinal segments were retrospectively reviewed from 2009 to 2021. Baseline patient characteristics, treatment and outcomes were abstracted. Primary endpoint was LF and secondary outcomes included overall survival (OS) and vertebral compression fracture (VCF) rates. OS was estimated using the Kaplan-Meier method. Cumulative LF and VCF rates were calculated using competing risk analysis method. Multivariable analysis (MVA) evaluated factors predictive of LF and VCF.

RESULTS

Median follow-up was 13 months (range, 0.5-95 months). Median OS was 18.4 months (95% CI 11.4-24.6). Median age was 67 years (range, 28.2-89.9). 52% were female, 76% had an adenocarcinoma histology and 61% had a smoking history. 49/165 (29%) had an EGFR mutation. PD-L1 status was analyzed in 109/165 (66%) patients with 16% PD-L1 ≥ 50%, 20% PD-L1 1-49% and 35% PD-L1 <1%. Of 389 segments, 79% were de novo and 21% were previously radiated. At baseline, 35% had a VCF, 27% had epidural disease, 27% had paraspinal extension, and 49% were Spinal Instability in Neoplasia Score (SINS) stable. 239/389 (61%) were treated with either 24 or 28 Gy in 2 SBRT fractions. Within 1 month of SBRT, 39/165 (24%) had a tyrosine kinase inhibitor, 27/165 (16%) immunotherapy (IO) with or without chemotherapy, and 31/165 (19%) chemotherapy alone. LF cumulative incidence at 1- and 2-years was 16.3% (95% CI 12.8-20.3%) and 25.4% (95% CI 20.9%-30%), respectively. EGFR positivity (p<0.0001), PD-L1≥50% (p = 0.013) and treatment with IO within 1 month of SBRT (p = 0.004) predicted for improved local control on MVA. The 1- and 2-year LF rate in EGFR-positive vs. negative patients were 12.9% vs. 16.6% and 17.7% vs. 28.8%, respectively, and in those PD-L1 ≥50% vs PD-L1<50% were 7.8% vs. 19.6% and 7.8% vs. 38.1% respectively. Cumulative incidence of VCF at 1- and 2-years were 6.6% (95% CI 4.4-9.4%) and 8.8% (95% CI 6.1-12.0%). MVA identified prior SBRT to the same treated segment (P<0.0001) and a baseline VCF (p<0.0001) as significant predictors. 18/389 (4.6%) had radiation-induced radiculopathy and no radiation myelopathy events detected.

CONCLUSION

We identify the predictive utility of EGFR mutation and PD-L1 ≥50% status on local control in NSCLC patients with spinal metastases treated with spine SBRT, and a therapeutic benefit with peri-SBRT IO.

Predictors of Tumor Dynamics during a 6-Week Course of Chemoradiotherapy for Glioblastoma

PURPOSE/OBJECTIVE(S)

Our prior imaging studies have shown geometrically meaningful inter-fraction tumor dynamics specific to glioblastoma (GBM). We aim to identify predictors associated with tumor dynamics during a 6-week course of concurrent chemoradiotherapy (CRT) for GBM.

MATERIALS/METHODS

Patients enrolled in a prospective serial magnetic resonance imaging (MRI) study were reviewed. All patients were treated with 54-60 Gy in 30 fractions. The gross tumor volume (GTV) included the surgical cavity and T1c enhanced residual tumor; clinical tumor volume (CTV) included GTV with a 15mm isotropic expansion, respecting anatomical boundaries; planning target volume (PTV) was 4mm expansion. MRIs were obtained at RT planning (F0), fraction 10 (F10), and fraction 20 (F20). Tumor dynamic metrics (relative to F0) assessed included the GTV volume (Vrel), Hausdorff distance (dH) and migration distance (dM). dH is the average distance between two datasets in metric space. dM is the maximum linear displacement of the GTV in any direction. Factors to be determined associated with tumor dynamics included: age, sex, corpus callosum (CC) involvement, extent of surgery (gross total resection (GTR), subtotal resection (STR) or biopsy alone (Bx)), MGMT methylation and IDH mutation status.

RESULTS

A total of 129 patients were reviewed. Median GTV was 20.9cc at F0, 17.6cc at F10 (Vrel 0.85), and 16.1cc at F20 (Vrel 0.78). Patients without CC involvement had more marked GTV volume reduction: Vrel 0.82 vs 1.02 with CC involvement at F10 (P = 0.05), and Vrel 0.77 vs 0.88 with CC involvement at F20 (P = 0.03). Patients with GTR (vs STR vs Bx) had more marked GTV volume reduction across all time points: Vrel 0.78, 0.85 and 1.07 respectively at F10 (P = 0.001), and Vrel 0.69, 0.80, 1.04 respectively at F20 (P = 0.001). The median dH was 8.1mm at F10 and 9.2mm at F20. Patients with CC involvement (vs without CC involvement) had a larger dH: 54% vs 25% had dH>10mm respectively at F10 (P = 0.03), and 73% vs 28% had dH>10mm respectively at F20 (P<0.005). Patients with a GTR had smaller dH at both F10 (P = 0.02) and F20 (P = 0.006). At F20, 20%, 47% and 37% of patients with GTR, STR and Bx had dH>10mm (P = 0.04). The median dM were 4.7mm at F10 and 4.7mm at F20. Patients with CC involvement (vs without CC involvement) had larger dM: 41% vs 12% had dM >10mm respectively at F10 (P = 0.01), and 45% vs 9% had dM >10mm respectively at F20 (P<0.001). Patients with GTR had smaller dM at F10 (P = 0.03) and F20 (P0.002). At F20, 0%, 25% and 19% of patients with GTR, STR and Bx had dM>10mm (P = 0.002). Age, sex, MGMT methylation and IDH mutation status were not associated with Vrel, dH and dM at F10 and F20.

CONCLUSION

We identified CC involvement and extent of surgery to be associated with tumor dynamics at F10 and F20 over the course of CRT for GBM. This offers opportunities to better select patients who may benefit from earlier/ more frequent RT replan/ adaptation to ensure adequate tumor coverage, or to reduce RT toxicities.

Stereotactic Body Radiotherapy (SBRT) for Sacral Metastases: Deviation from Recommended Target Volume Delineation Predicts Higher Risk of Local Failure

PURPOSE/OBJECTIVE(S)

A international consensus recommendation was published to guide target volume delineation specific to sacral stereotactic body radiotherapy (SBRT). We report outcomes after sacrum SBRT, focusing on the impact of contouring deviation on local failure (LF) risk, with an aim to validate this guideline.

MATERIALS/METHODS

All patients who underwent SBRT to any level between S1 and S5 from 2010 to 2021 were identified from a prospectively maintained institutional database. The primary outcome was magnetic resonance-based LF. Secondary outcomes included vertebral compression fracture (VCF) and overall survival (OS). Cumulative LF and VCF rates were calculated per segment using the competing risk analysis method. Kaplan Meier analysis was used to estimate OS per patient. Cox proportional hazards model was used to assess predictive factors of LF, VCF, and OS.

RESULTS

A total of 215 treated sacral segments in 112 patients were retrospectively reviewed. The median follow-up was 13 months (range, 0.4-116.9). The median age was 64 years (range, 18-86), and 56% were male. Most patients (52%) had treatment to a single segment. The median clinical target volume (CTV) was 129.2 cc (range, 5.8-753.5). Most segments were treated with 30 Gy/4 fractions (51%), 24 Gy/2 fractions (31%), or 30 Gy/5 fractions (10%). Thirty-one percent of segments were of radioresistant histology (gastrointestinal, kidney, melanoma, sarcoma, or thyroid primary), and 51% had extraosseous disease. Sixteen percent of segments were under-contoured per consensus guidelines, with incomplete coverage of the involved sector (71%), omission of the adjacent uninvolved sector (17%), or both (11%) as the causes for deviation. The cumulative incidence of LF was 18.4% (95% CI 13.5-24.0) at 12-months and 23.1% (95% CI 17.6-29.0) at 24-months. On multivariate analysis (MVA), under-contouring (HR 2.4, 95% CI 1.3-4.7, p = 0.008), radioresistant histology (HR 2.4, 95% CI 1,4-4.1, p = 0.001), and extraosseous extension (HR 2.5, 95% CI 1.3-4.7, p = 0.005) were predictors of increased risk of LF. The LF rates at 12/24-months were 15.1%/18.8% for segments contoured per guideline versus 31.4%/40.0% for those under-contoured. The cumulative incidence of VCF was 7.1% (95% CI 4.1-11.1) at 12-months and 12.3% (95% CI 8.2-17.2) at 24-months. On MVA, female gender was the only risk factor for VCF (HR 2.3, 95% CI 1.1-5.2, p = 0.04). The median OS was 29.5 months (95% CI 17.5-59.2). On MVA, primary kidney (HR 4.7, 95% CI 1.7-12.5, p = 0.002) or lung histology (HR 3.4, 95% CI 1.3-8.5, p = 0.010), the presence of liver (HR 2.8, 95% CI 1.2-6.4, p = 0.016) or lung (HR 2.5, 95% CI 1.3-5.1, p = 0.008) metastases, ECOG performance status 2 or 3 (HR 3.3, 95% CI 1.2-8.2, p = 0.013), and the presence of sensory or motor deficit (HR 2.6, 95% CI 1.2-5.4, p = 0.012) were prognostic for worse OS.

CONCLUSION

Sacral SBRT is associated with high rates of efficacy and an acceptable VCF risk. Adherence to target volume delineation consensus guidelines reduces the risk of LF.

Dosimetric Implications of Weekly On-Line MR-Guided Adaptive Radiotherapy (RT) for Glioblastomas (GBM) Growing during RT

PURPOSE/OBJECTIVE(S)

The UNITED trial (NCT04726397) involves once-weekly on-line adaptive RT for patients with GBM on a 1.5T MRI-Linac (MRL). For tumors that continue to enlarge during the course of RT, we hypothesize that the adaptive strategy improves the dosimetric coverage of the target relative to a non-adaptive strategy.

MATERIALS/METHODS

As per the trial protocol, T1+contrast (T1c) and FLAIR MRI sequences were acquired once per week during RT to re-define and adapt the gross tumor volume (GTV) as the contrast enhanced volume, the clinical target volume (CTV) as a 5mm expansion around the GTV plus adjacent FLAIR hyperintense regions considered at-risk by the radiation oncologist, and a 3 mm PTV around the CTV. Nine UNITED patients with tumors that grew throughout RT (GTV and/or CTV) were identified. 5/9 patients were treated with 60 Gy in 30 fractions (6 weekly adaptions) and 4/9 with 40 Gy in 15 fractions (3 weekly adaptions). For the final week's GTV and CTV (GTVfinal and CTVfinal), the dosimetric outcomes of the delivered and adaptive summative plans (Dsum) were compared to dose of the baseline plan (Dbaseline) generated on Fraction 1 of treatment, the latter being indicative of the theoretical situation where no further adaption was taken. We measured the dose to 99% of the GTVfinal and CTVfinal: Dsum99 and Dbaseline99.

RESULTS

For each adaptive fraction, the plan was optimized to achieve an objective of D99 greater than 95% of the prescription (D99>95%) for both the GTV and CTV. The relative increase in GTVfinal and CTVfinal from baseline was on average 119% (range: 98% to 144.7%) and 128% (range: 109% to 176%), respectively. The proportion of CTVfinal that was outside the baseline plan's PTV was on average 11.5% (range: 0% to 32%). The GTVfinal did not extend beyond the baseline PTV for any of the 9 cases. GTVfinal Dsum99 was >95% for all cases while CTVfinal Dsum99 was < 95% in 2 of 9 cases (74%, and 87%). By contrast, the baseline plan, if given for all fractions with no further adaptation, yielded a D99 for CTVfinal of <95% in 5 of 9 cases (28%, 52%, 75%, 84%, and 87%). In general, coverage of the CTVfinal decreased with increasing levels of CTVfinal outside of the baseline PTV. For all 5 cases where CTVfinal D99<95% on the baseline plan, more than 10% of CTVfinal was outside of the baseline PTV. Small margin, weekly adaptive RT on an MRL for GBM maintains coverage of the GTV in the presence of tumor growth while minimizing the degree of normal brain tissue irradiated. Dosimetric impact on non-GTV/CTV brain is outside the scope of the present study.

CONCLUSION

Preliminary results indicate that a once weekly adaptive approach for small margin MR-guided RT improves tumor coverage for progressive tumors compared to a static (baseline) plan without adaptation.

Dosimetric Parameters Predictive of Treatment-Related Toxicity in High Dose-Rate Brachytherapy as Monotherapy for Prostate Cancer

PURPOSE/OBJECTIVE(S)

High dose-rate (HDR) brachytherapy as monotherapy is an effective treatment for patients with low- and intermediate-risk prostate cancer and is increasingly being offered as a 2-fraction protocol. There is a lack of consensus on the optimal dosimetric planning parameters to use, or whether there is any benefit summating dosimetric parameters from more than one implant. Our goal is to determine planning parameters associated with disease control, toxicity and health-related quality of life (HRQOL).

MATERIALS/METHODS

Data were collected on 83 patients with low- and intermediate-risk prostate cancer who received 2 fractions of 13.5 Gy HDR brachytherapy without androgen-deprivation therapy as part of a randomized phase II clinical trial. An in-house deformable, registration algorithm was used to co-register and dose-summate the plans from both implants for each patient. Acute and late GU and GI toxicities were measured using CTCAE 4.0 and HRQOL was measured in urinary, bowel, sexual and hormonal domains using the EPIC scores. Treatment efficacy was assessed through PSA measurement and imaging with or without biopsy where indicated. Covariates included baseline clinical factors, disease characteristics and treatment dosimetric parameters. Cox proportional hazards was performed to evaluate covariates impact on treatment toxicity and efficacy, and logistic regression analysis evaluated covariates impact on HRQOL.

RESULTS

Among the 83 patients, median prostate volume was 46.7cm3. Median summated planning target volume receiving 100% prescription dose (PTV V100%) was 97.4%, median PTV V150% 42.4% and median PTV V200% 15.5%. Median highest dose to the 1cm3 rectum (D1cc) was 66.9% of the prescription dose and median rectum V80% was 0.008cm3. Median urethral D1cc was 99.0% of the prescription dose, median urethral Dmax 121.7% and median urethral D10% 116.2%. Grade ≥2 GI toxicity was uncommon (3.7% acute and 8.5% late), but grade ≥2 GU toxicity was reported in 73.2% (acute) and 46.3% (late) patients. Rectum D1cc and V80% were found to be significantly associated with grade 2 or higher acute GI toxicity, while use of a-blocker at baseline was associated with grade ≥2 acute GU toxicity. Similarly, use of a-blocker was associated with late grade ≥2 GU toxicity, but with no dosimetric associations. No other variables were associated with treatment-related toxicities. Only rectum D1cc was significantly associated with changes in bowel EPIC scores. Estimated 5-year biochemical disease-free survival was 93.9% and 5-year cumulative incidence of local failure was 3.8%.

CONCLUSION

HDR monotherapy with 27 Gy delivered in 2 fractions in treatment of prostate cancer is well tolerated with high rates of disease control and minimal toxicity. Dose summation between 2 fractions of HDR brachytherapy is feasible, with rectal dose predicting acute GI toxicity. The lack of association between dose metrics and urinary toxicity raises the potential for further dose escalation.

Dosimetric Predictors of Toxicities and Quality of Life Following Two-Fraction Stereotactic Body Radiotherapy for Prostate Cancer

PURPOSE/OBJECTIVE(S)

There is emerging interest in two-fraction stereotactic body radiotherapy (2#SBRT) for localized prostate cancer. However, there is limited data to guide organs at risk (OAR) dose constraints in 2#SBRT. We aim to identify dosimetric predictors of toxicities and quality of life (QoL) using real life patient data from two prospective 2#SBRT trials.

MATERIALS/METHODS

We included 60 patients who had 2#SBRT in the 2STAR (NCT02031328) and 2SMART (NCT03588819) phase 2 trials. The prescribed dose was 26Gy to the prostate +/- focal boost of 32Gy to the dominant intraprostatic lesions. Toxicities and QoL data were prospectively collected using CTCAEv4 and EPIC26 questionnaires. For QoL, we reported the minimal clinical important changes (MCIC), defined as changes in QoL score of >0.5 standard deviation from baseline QoL score. We evaluated the bladder, urethra, rectum, and penile bulb dosimetry (urethra dosimetry only available in 30 patients in 2SMART trial). Some of the dosimetric parameters were log-transformed to normalize the distribution. Cox regression was used to identify dosimetric predictors for acute and late grade ≥2 GU toxicities. Logistic regression was used to identify dosimetric predictors for late MCIC in urinary, bowel and sexual QoL domains. Backward stepwise selection was used to identify significant dosimetric parameters. For GU toxicities and urinary QoL, three additional clinical factors (age, prostate volume and IPSS) were included in the final model as confounding factors. Receiver operating characteristics curve was used to identify cut-off for significant dosimetric parameters.

RESULTS

The median follow-up for the cohort was 56 months (range: 39-78 months). The cumulative acute and late grade ³2 GU toxicities were 62% (37/60) and 57% (34/60) respectively. No bladder or urethra dosimetric parameter was associated with acute grade ≥2 GU toxicities. Bladder D0.5cc was significant predictor of late grade ≥2 GU toxicities in univariate model (P = 0.05), but not in multivariate model. Baseline IPSS score was the single strongest predictor for late grade ≥2 GU toxicities (HR = 1.9; 95% CI = 1.1-3.4; P = 0.03). For late QoL outcomes, there were 36% (21/58), 28% (16/58), and 29% (17/58) of patients with MCIC in urinary, bowel and sexual QoL domains respectively. Bladder V10Gy was associated with late urinary MCIC in multivariate model after adjusting for clinical confounders (HR = 2.6, 95% CI = 1.1-6.6; P = 0.04). 48% (14/29) and 24% (7/29) of patients with bladder V10Gy>13.9% and V10Gy≤13.9% respectively had late urinary MCIC. No rectum and penile bulb dosimetry parameters was identified to be associated with late bowel or sexual QoL.

CONCLUSION

Using real life patient data from prospective clinical trials with medium term follow-up, we identified statistically significant bladder dosimetry parameter predictive of late urinary QoL. This finding could be useful to guide OAR dose constraints in prostate 2#SBRT trials.

Results of 15 Gy HDR-BT boost plus EBRT in intermediate-risk prostate cancer: Analysis of over 500 patients

PURPOSE/OBJECTIVE

To report biochemical control associated with single fraction 15 Gy high-dose-rate brachytherapy (HDR-BT) boost followed by external beam radiation (EBRT) in patients with intermediate-risk prostate cancer.

MATERIALS AND METHODS

A retrospective chart review of all patients with intermediate-risk disease treated with a real-time ultrasound-based 15 Gy HDR-BT boost followed by EBRT between 2009 and 2016 at a single quaternary cancer center was performed. Freedom from biochemical failure (FFBF), cumulative incidence of androgen deprivation therapy use for biochemical or clinical failure post-treatment (CI of ADT) and metastasis-free survival (MFS) outcomes were measured.

RESULTS

518 patients met the inclusion criteria for this study. Median age at HDR-BT was 67 years (IQR 61-72). 506 (98%) had complete pathologic information available. Of these, 146 (28%) had favorable (FIR) and 360 (69%) had unfavorable (UIR) intermediate-risk disease. 83 (16%) received short course hormones with EBRT + HDR. Median overall follow-up was 5.2 years. FFBF was 91 (88-94)% at 5 years. Five-year FFBF was 94 (89-99)% and 89 (85-94)% in FIR and UIR patients, respectively (p = 0.045). CI of ADT was 4 (2-6)% at 5 years. Five-year CI of ADT was 1 (0-3)% and 5 (2-8)% in FIR and UIR patients, respectively (p = 0.085). MFS was 97 (95-98)% at 5 years. Five-year MFS was 100 (N/A-100)% and 95 (92-98)% in FIR and UIR patients, respectively (p = 0.020).

CONCLUSION

In this large cohort of intermediate-risk prostate cancer patients, 15 Gy HDR-BT boost plus EBRT results in durable biochemical control and low rates of ADT use for biochemical failure.

Absolute percentage of biopsied tissue positive for Gleason pattern 4 disease (APP4) appears predictive of disease control after high dose rate brachytherapy and external beam radiotherapy in intermediate risk prostate cancer

BACKGROUND AND PURPOSE

To identify if, in intermediate risk prostate cancer (IR-PCa), the absolute percentage of biopsied tissue positive for pattern 4 disease (APP4) may be a predictor of outcome.

MATERIALS AND METHODS

411 patients with IR-PCa were retrospectively reviewed. APP4 was calculated based on biopsy reports. Multivariable competing risk analysis was then performed on optimized APP4 cutpoints to predict for biochemical failure (BF), androgen deprivation use for BF (ADT-BF) and development of metastases (MD).

RESULTS

Median follow-up for the cohort was 5.2 (Inter Quartile Range: 2.9-6.6) years. Median baseline PSA was 7.3 (5.3-9.8) ng/mL. 234 (56.9%) patients had T1 and 177 (43.1%) had T2 disease. Median APP4 was 2.00 (0.75-7.50)%. 38 (9.3%) patients experienced BF. The optimal cutpoint of APP4 for BF was >3.3% with an area under the curve (AUC) of 0.66. 17 (4.1%) received ADT-BF. The ADT-BF cutpoint was >6.6% with an AUC of 0.72. Eight (2.0%) developed MD. The MD cutpoint was >17.5% with an AUC of 0.86. Using APP4 >3.3 vs ≤ 3.3, log-transformed baseline PSA ln(PSA) (HR 2.5, 1.1-6.1; p = 0.037) and APP4 (HR 2.3, 1.1-4.7; p = 0.031) predicted for BF. Using APP4 >6.6 vs ≤ 6.6, ln(PSA) (HR 4.2, 1.4-12.4; p = 0.010) and APP4 (HR 3.7, 1.4-10.0; p = 0.009) were predictive of ADT-BF. APP4 >17.5 vs ≤ 17.5 alone was predictive of MD (HR 25.7, 4.9-135.3; p < 0.001).

CONCLUSION

APP4 cutpoints of >3.3%, >6.6% and >17.5% were strongly associated with increased risk of BF, ADT-BF and developing MD respectively. These findings may inform future practice when treating IR-PCa but require external validation.

Inter-observer agreement in GTV delineation of bone metastases on CT and impact of MR imaging: A multicenter study

BACKGROUND AND PURPOSE

The use of Stereotactic Body Radiotherapy (SBRT) for bone metastases is increasing rapidly. Therefore, knowledge of the inter-observer differences in tumor volume delineation is essential to guarantee precise dose delivery. The aim of this study is to compare inter-observer agreement in bone metastases delineated on different imaging modalities.

MATERIAL AND METHODS

Twenty consecutive patients with bone metastases treated with SBRT were selected. All patients received CT and MR imaging in treatment position prior to SBRT. Five observers from three institutions independently delineated gross tumor volume (GTV) on CT alone, CT with co-registered MRI and MRI alone. Four contours per imaging modality per patient were available, as one set of contours was shared by 2 observers. Inter-observer agreement, expressed in generalized conformity index [CIgen], volumes of contours and contours center of mass (COM) were calculated per patient and imaging modality.

RESULTS

Mean GTV delineated on MR (45.9±52.0cm³) was significantly larger compared to CT-MR (40.2±49.4cm³) and CT (34.8±41.8cm³). A considerable variation in CIgen was found on CT (mean 0.46, range 0.15-0.75) and CT-MRI (mean 0.54, range 0.17-0.71). The highest agreement was found on MRI (mean 0.56, range 0.20-0.77). The largest variations of COM were found in anterior-posterior direction for all imaging modalities.

CONCLUSIONS

Large inter-observer variation in GTV delineation exists for CT, CT-MRI and MRI. MRI-based GTV delineation resulted in larger volumes and highest consistency between observers.

Determination of trace Al in silicon carbide by epithermal neutron activation

An approach based on utilization of epithermal neutron activation analysis (ENAA) is proposed for determination of trace Al in silicon carbide (SiC) materials. The feasibility and restrictions of the ENAA were evaluated in terms of the associated uncertainties that resulted from counting and from propagation in calculations. Experimental measurements were carried out under the specified irradiation and measurement conditions, where the results of a set of SiC standards for accuracy testing were compared with the calculated uncertainties. It is shown that the epithermal neutron activation is a simple and reliable method practically useful for analysis of SiC containing Al in concentrations (f(Al)) higher than 10(-3) weight fraction by the use of a typical nuclear reactor; the associated uncertainties can be suppressed to less than 12%. The influences of neutron quality or the cadmium ratio in 27Al(n,gamma)28Al reaction on the applicable concentrations of Al in SiC are also predicted and discussed.

Using color histogram normalization for recovering chromatic illumination-changed images

We propose a novel image-recovery method using the covariance matrix of the red-green-blue (R-G-B) color histogram and tensor theories. The image-recovery method is called the color histogram normalization algorithm. It is known that the color histograms of an image taken under varied illuminations are related by a general affine transformation of the R-G-B coordinates when the illumination is changed. We propose a simplified affine model for application with illumination variation. This simplified affine model considers the effects of only three basic forms of distortion: translation, scaling, and rotation. According to this principle, we can estimate the affine transformation matrix necessary to recover images whose color distributions are varied as a result of illumination changes. We compare the normalized color histogram of the standard image with that of the tested image. By performing some operations of simple linear algebra, we can estimate the matrix of the affine transformation between two images under different illuminations. To demonstrate the performance of the proposed algorithm, we divide the experiments into two parts: computer-simulated images and real images corresponding to illumination changes. Simulation results show that the proposed algorithm is effective for both types of images. We also explain the noise-sensitive skew-rotation estimation that exists in the general affine model and demonstrate that the proposed simplified affine model without the use of skew rotation is better than the general affine model for such applications.

Characterization and modeling of the metal diffusion from deep ultraviolet photoresist and silicon-based substrate

The radioactive tracer technique was applied to investigate the out-diffusion of the transition metals (Cu, Fe and Co) from deep ultraviolet (DUV) photoresist into underlying substrate. Two important process parameters, viz., baking temperatures and substrate types (i.e., bare silicon, polysilicon, silicon oxide and silicon nitride), were evaluated. Results indicate that the out-diffusion of Co is insignificant, irrespective of the substrate type and baking temperature. The out-diffusion of Cu is significant for substrates of bare silicon and polysilicon but not for silicon oxide and nitride; for Fe, the story is reversed. The substrate type appears to strongly affect the diffusion, while the baking temperature does not. Also, the effect of solvent evaporation was found to play an important role in impurity diffusion. Using the method of numerical analysis, a diffusion profile was depicted in this work to describe the out-diffusion of metallic impurities from photoresist layer under various baking conditions. In addition, the effectiveness of various wet-cleaning recipes in removing metallic impurities such as Cu, Fe and Co was also studied using the radioactive tracer technique. Among the six cleaning solutions studied, SC2 and SPM are the most effective in impurity removal. An out-diffusion cleaning model was first proposed to describe the cleaning process. A new cleaning coefficient, h(T), was suggested to explain the cleaning effect. The cleaning model could explain the tracer results.

Dose estimation for repeated phosphorus-32 ingestion in human subjects

Dose estimation was conducted for internal phosphorus-32 exposure in one young male subject from repeated oral mis-ingestion for > 1 year. Since disclosure for previous continuous contamination, a series of urine samples were collected from this individual weekly for a period of >2 months. P-32 radioactivity in urine samples were measured by the acid precipitation method. Estimation for retrospective total effective dose equivalent received by this subject was conducted for cumulative internal dose estimation. A minimum of 9.4 mSv was estimated for an assumed single ingestion. As this was a rare case in radiation protection and internal radiation dosimetry, its implications were of considerable significance.

Frequency and clinical determinants of dementia after ischemic stroke

OBJECTIVE

To investigate the frequency and clinical determinants of dementia after ischemic stroke.

METHODS

The authors administered neurologic, neuropsychological, and functional assessments to 453 patients (age 72.0 +/- 8.3 years) 3 months after ischemic stroke. They diagnosed dementia using modified Diagnostic and Statistical Manual of Mental Disorders, 3rd ed., revised criteria requiring deficits in memory and two or more additional cognitive domains as well as functional impairment.

RESULTS

The authors diagnosed dementia in 119 of the 453 patients (26.3%). Regarding dementia subtypes, 68 of the 119 patients (57.1%) were diagnosed with vascular dementia, 46 patients (38.7%) were diagnosed with AD with concomitant stroke, and 5 patients (4.2%) had dementia for other reasons. Logistic regression suggested that dementia was associated with a major hemispheral stroke syndrome (OR 3.0), left hemisphere (OR 2.1) and right hemisphere (OR 1.8) infarct locations versus brainstem/cerebellar locations, infarcts in the pooled anterior and posterior cerebral artery territories versus infarcts in other vascular territories (OR 1.7), diabetes mellitus (OR 1.8), prior stroke (OR 1.7), age 80 years or older (OR 12.7) and 70 to 79 years (OR 3.9) versus 60 to 69 years, 8 or fewer years of education (OR 4.1) and 9 to 12 years of education (OR 3.0) versus 13 or more years of education, black race (OR 2.6) and Hispanic ethnicity (OR 3.1) versus white race, and northern Manhattan residence (OR 1.6).

CONCLUSIONS

Dementia is frequent after ischemic stroke, occurring in one-fourth of the elderly patients in the authors' cohort. The clinical determinants of dementia include the location and severity of the presenting stroke, vascular risk factors such as diabetes mellitus and prior stroke, and host characteristics such as older age, fewer years of education, and nonwhite race/ethnicity. The results also suggest that concomitant AD plays an etiologic role in approximately one-third of cases of dementia after stroke.

Treatment for the secondary prevention of stroke in older patients: the influence of dementia status

OBJECTIVE

To investigate the influence of dementia status on treatment for the secondary prevention of stroke in older patients.

DESIGN

Based on patient examinations and medical record review, we investigated the frequency of aspirin and/or warfarin use at hospital discharge for the prevention of recurrent stroke in older patients hospitalized with acute ischemic stroke.

SETTING

A large academic medical center.

PARTICIPANTS

A cohort of 272 patients, mean age 72.1 +/- 8.5 years.

MEASUREMENTS

We performed neurologic examinations and reviewed medical records to investigate the effects of a clinical diagnosis of dementia and other potentially relevant factors on treatment with aspirin or warfarin at hospital discharge.

RESULTS

Thirty-one patients (11.4%) were not prescribed aspirin or warfarin at hospital discharge. Logistic regression determined that dementia (odds ratio (OR) = 2.57, 95% confidence interval (CI), 1.04-6.30) was a significant independent determinant of nontreatment with aspirin or warfarin, adjusting for abnormal gait (OR = 2.01, CI, .88-4.59); discharge to a nursing home or other institutional residence (OR = 2.55, CI, .83-7.81); cardiac disease (OR = .39, CI, .16-.95); cortical infarct location (OR = .45, CI, .18-1.10); male sex (OR = .47, CI, .20-1.15); age 80+ (OR = 1.14, CI, .46-2.82) and age 70-79 (OR = .96, CI, .32-2.88) versus age 60-69.

CONCLUSIONS

Our results suggest that dementia is a significant independent determinant of nontreatment with aspirin or warfarin when otherwise indicated for the prevention of recurrent stroke. The underutilization of aspirin and warfarin in older stroke patients with dementia may be a modifiable basis for their increased risk of recurrence and death.

Intracranial arachnoid cysts in children: related signs and associated anomalies

Intracranial arachnoid cysts are benign development anomalies that may be clinically asymptomatic. The authors describe 30 children with intracranial arachnoid cysts in terms of clinical manifestations and relations to the associated brain anomalies or lesions. The mean age at onset of clinical manifestations was 4 years, 7 months (range 1 day to 14 years). The mean age at diagnosis was 6 years, 2 months (range 10 days to 16 years). Most patients with nonprogressive symptoms, such as seizures and headache, had focal epileptiform discharges on electroencephalogram, and they benefited from antiepileptic drugs. Surgery resulted in only partial reduction in both cyst size and seizure frequency in patients with intractable seizures, and it also failed to improve some neurologic signs, such as sexual precocity or cranial neuropathy resulting from long-term compression of arachnoid cysts. We conclude that the only absolute indication for surgery is the presence of progressive hydrocephalus or intracranial hypertension. The associated anomalies or lesions include brain tumors, giant nevocellular nevi, achondroplasia, microphthalmia, intracystic hemorrhage, dysgenesis of the corpus callosum, and heterotopia.

Comparing predictors of willingness to treat HIV+ patients for New York City male and female general practice dentists 50 years of age or younger

OBJECTIVES

This article develops and compares gender-specific predictive models for willingness to treat HIV-infected patients (PHIV+) for male and female private general practice dentists (GPDs).

METHODS

Based on mail survey data collected in Manhattan and Queens, New York City (73.3% response rate), hierarchical multiple regression analyses were conducted for male and female dentists 50 years of age or younger (n = 763) and for those in solo practice.

RESULTS

The gender-specific predictive models (R2s = 0.72) do not differ, except for the influence of practice viability, a moderately strong, statistically significant predictor for men, while the least powerful, statistically nonsignificant predictor for women. This distinction remains for solo male and female practitioners. Informal/formal collegial norms are more influential predictors within the solo female model than within the solo male model.

CONCLUSIONS

Findings are encouraging for further work in developing predictive models for clinician subpopulations, with an eye toward developing intervention strategies that reflect key predictive factors for each group.

Magnetic resonance imaging in symptomatic/cryptogenic partial epilepsies of infants and children

In order to identify the brain lesions of symptomatic/cryptogenic partial epilepsies (S/CPEs) in infants and children, magnetic resonance imaging (MRI) studies, thorough encephalographic (EEGic) studies, and detailed clinical and neurologic evaluations were obtained in 300 infants and children who were diagnosed to have S/CPEs with onset before the age of 13 years during the past 7 years. The overall detection rate of brain lesions by MRI was 41.7% (125/300). Congenital malformations (18 cases), vascular malformations (9 cases), neurocutaneous syndromes (13 cases), and space-taking lesions (20 cases) constitute a large percentage of SPEs in infants and children. A variety of insults such as infection, ischemia, hemorrhage, trauma and metabolic disorders can result in destructive parenchymal loss lesions including porencephaly, focal atrophy, hemiatrophy, and diffuse brain atrophy (20 cases). Major etiologic factors leading to infarction, encephalomalacia, leukomalacia, included trauma, hvpoxicischemic encephalopathy (HIE), systemic lupus erythematosus (SLE), encephalitis, vasculitis, venous thrombosis, vasculopathies, and heart problems (22 cases). Mesial temporal sclerosis (MTS) could be evidenced in around 20% (18/95) of cases with temporal lobe epilepsy (TLE), which was strongly associated with past histories of febrile seizures and encephalitis complicated by status epileptics. However, cases with porencephaly, global atrophy or delayed myelination of unilateral temporal lobe on MRI were more related to HIE. With the advent of neuroimaging techniques, particularly MRI, a wide variety of underlying pathology can be detected as a cause of symptomatic partial epilepsies in pediatric patients. The occurrence of S/CPE indicates the presence of localized brain dysfunction, and many of the causes are potentially treatable. An orderly and thorough clinical and laboratory investigations, as well as neuroimaging studies should be made to diagnose and treat any underlying conditions.

129I concentrations of mammalian thyroids in Taiwan

The 129I and 129I/127I ratios in mammalian thyroids were determined by neutron activation analysis to estimate the 129I concentrations in the biosphere due to fallout accumulation during the past decades in this island. The average 129I/127I ratio in thyroids of grazing animals, bovine and ovine, is about 1 x 10(-9), three times higher than that of hogs. The 129I/127I ratio in twin water collected during the same period was found to be as high as 1.7 x 10(-8) and it is supposed to be the predominant source of 129I in the biosphere. The 129I concentrations in these mammalian thyroids are similar to those of non-direct contamination areas of the world, where the terrestrial 129I contents are influenced by the global fallout.

Acute disseminated encephalomyelitis in children: clinical, neuroimaging and neurophysiologic studies

Nine patients below 20 years of age (4 males and 5 females), who were diagnosed to have acute disseminated encephalomyelitis (ADEM) by clinical findings and magnetic resonance imaging (MRI), were reviewed retrospectively. They ranged from 4 months to 20 years of age with an average of 8.6 years. Seven patients (78%) received neurophysiological studies, which included electroencephalography, multimodality evoked potentials (EPs), nerve conduction velocity and/or F-wave measurement. The presentation symptoms were mainly headache, vomiting, consciousness change and motor deficits. Seven (78%) of nine patients had symptoms preceded by fever or upper respiratory tract infections; one (11%) was preceded by trivalent mumps, measles, rubella vaccination and no definite predisposing factor was found in another. Computed tomography (CT) scans were abnormal in five (71 %) of seven children, while MRI showed multiple lesions in seven (78%) of nine children. The lesions in MRI were mainly in the brainstem (n = 6), basal ganglion (n = 5), thalamus (n = 4), periventricular white matter (n = 4) and cerebellum (n = 4). EPs disclosed spinal cord involvement in all patients who received the examination. Peripheral neuropathy was disclosed in one patient. It was concluded that associated radiculoneuropathy is possible in patients with ADEM. Both MRI and neurophysiologic studies are complementary for diagnosis of ADEM.

Multiple sclerosis in children: clinical, neuroimaging, and neurophysiological correlations

Four female children with clinically-definite diagnoses of multiple sclerosis (MS) were studied with multimodal evoked potentials (EPs), electroencephalogram (EEG), cerebrospinal fluid (CSF) analysis, computed tomography (CT) and magnetic resonance imaging (MRI). Correlations among the clinical features, neuroimaging and neurophysiological studies were also evaluated. Their ages of the onset ranged from 5 to 11 years. The clinical evolution in the all four MS cases was relapsing-remitting form. MRI studies in three cases showed abnormal demyelinating plaques in the brainstem, cerebellum and white matter of the cerebrum. CT examination, performed in the other MS case, did not reveal hypodensic lesion. Despite that MRI failed to document optical nerve lesions, three cases had abnormal visual evoked potentials (VEPs). Somatosensory evoked potentials (SSEPs) were abnormal in three cases. Brainstem auditory evoked potentials (BAEPs) were abnormal in two cases presenting with signs of brainstem dysfunction. The conclusion was that paraclinical evidences obtained from MRI and multimodal evoked potential studies are of value as an aid in localizing involved areas and detecting silent lesions in children with MS.

Trace elements in hair of Blackfoot disease

Blackfoot disease is a peripheral vascular disease resulting in gangrene of the lower extremities. Though extensive epidemiological study has implicated that high arsenic content in artesian well water of the endemic area bears some important connection with the disease, the etiology of the disease is still unknown. In this study, attention is paid to multielement determination in order to find out whether the trace elements in hair of Blackfoot disease patients are different from those of the controls. Experimental results indicate that the concentrations of As and Se in hair of patients are significantly higher than those of the controls, but Ca and Zn are significantly lower than those of the controls. The possible connection of these elements with the etiology of the disease is discussed.

[The effect of intracranial pressure caused by airway suction in hypertensive intracerebral hemorrhagic comatose patients]

Ten hypertensive intracerebral hemorrhagic comatose patients in the Neurosurgical Intensive Care Unit were involved in this study. The ten were within the range of 5 to 8 by Glasgow Coma Scale, and all had undergone tracheostomy. During suction of the airway for 20 seconds in 4 areas (trachea, bronchus, nasal and oral cavities), the data of intracranial pressure (ICP), arterial blood pressure, pulse rate (PR) and respiration rate (RR) were recorded. Results were analyzed for ICP, mean arterial blood pressure (MABP), PR, RR, and cerebral perfusion pressure (CPP) at the 5th, 10th, 15th and 20th seconds in the above-mentioned areas. The ICP was found to be significantly increased, and above the 20 mmHg mark, during suction of the bronchus or nasal cavity for 5 seconds. The MABP also showed significant increase, to above the 110 mmHg mark during 5-second suction of the trachea or nasal cavity or during suction of the bronchus or oral cavity for 10 seconds. However, during the suction of the four airway areas, PR and RR were less influenced and the CPP was not decreased or significantly changed. The conclusion of this study was that suction in the areas of trachea, bronchus and nasal cavity, should not exceed 5 to 10 seconds; in the oral cavity, it may be done within 10 to 15 seconds and at each procedure of airway suction. If it is not possible to clean the sputum or secretion in one procedure, the patient should be allowed to rest for about one minute or become stabilized as determined by watching the monitors of ICP, BP, PR, and RR.(ABSTRACT TRUNCATED AT 250 WORDS)

Analyses of radioactive aerosols to support accurate internal dose assessments at Chin-Shan nuclear power plant

Studies of the physical and chemical properties of radioactive aerosols produced in different work environments were made at Chin-Shan nuclear power plant in Taiwan. These properties, including particle mass- and activity-size distributions, elemental and radionuclide compositions, and solubility lung class, are essential for the assessment of internal dose equivalents from the inhalation of radioactive aerosols. Several practices and environments studied include thermal arc cutting, grinding, sandblasting, and noble gas progeny. For physical analyses, cascade impactors, scanning electron microscopy with energy-dispersive x-ray analysis, inductively coupled plasma atomic emission spectrometry, and neutron activation analysis were applied. For chemical analyses, the solubility lung class was determined, in vitro, with the measurement of aerosol dissolution rates in simulated biological fluids. Results of these analyses were used to calculate the annual limit on intake, the derived air concentration, and committed dose equivalents for radiological protection against radioactive aerosols produced at Chin-Shan nuclear power plant.

Urinary N-acetyl-beta-glucosaminidase (NAG) in children receiving antiepileptic drugs

The activity of urinary N-acetyl-beta-glucosaminidase (NAG) was measured in random urines using the ratio (NAG index) of NAG to grams of urine creatinine in 102 epileptic children taking antiepileptic drugs (AEDs). A high urinary NAG index (2 SD or more above the mean for the age-matched control/normal subjects) was detected in 40 (39%, 40/102) epileptic children with AEDs. None of the 40 epileptic children with abnormal urinary NAG excretion had significant proteinuria. Among the 83 epileptic children under monotherapy, 29 cases (35%) had elevated urinary NAG excretion. Valproic acid presented the highest incidence of abnormal urinary NAG index (78%, 7/9 cases) within the monotherapy group, and the incidence was statistically significantly higher than that (26%, 14/55) in the carbamazepine group (p < 0.005). In the monotherapy group, no significant difference in serum levels of AEDs was found between children with normal urinary NAG excretion and those with abnormal. Nineteen epileptic children were treated with more than one AEDs. Eleven of them (58%, 11/19 cases) had a high urinary NAG index. The incidence of high urinary NAG index in the polytherapy group and that in monotherapy group was not significantly different (p > 0.05). This study suggests that AEDs may be potentially nephrotoxic and that urinary NAG may play a role in screening renal tubular injury in epileptic children under therapy of AEDs. Further investigation should be conducted to determine whether the effect of AEDs on renal tubular cells is or is not reversible.

Electroencephalographic and clinical features of typical absence seizures in children

From July 1986 to July 1991, seventeen typical absence seizures, in patients aged 3 to 12 years (mean: 7 years 1 month), were collected for clinical and electroencephalographic (EEG) analysis. All were first-evaluated patients at the Pediatric Neurology Clinic, National Taiwan University Hospital with thorough EEG examination (including waking and natural sleep records) and detailed medical records. All had no history of any brain insult, except for one who had had febrile convulsion before. There were nine female and eight male patients. All had regular bilaterally synchronous and symmetric 3 Hz spike-and-wave discharges and absences. Nine of the 17 cases had interictal focal spike discharges, located over centro-temporal area in 4 cases, fronto-central area in 2 cases and parietooccipital area in the other 2 cases. Another patient was found to have 3 Hz posterior slow waves. Four of the 17 cases had automatisms. Only one case had photo-paroxysmal response. Hyperventilation could induce clinical spells and typical EEG findings in all 17. Normal interictal background activity on the EEG was also found in all cases.

Analysis and clinical correlates of the 14 and 6 Hz positive electroencephalographic spikes in Chinese children

From January 1987 to March 1991, electroencephalographic (EEG) analysis and clinical correlates of the 14 and 6 Hz positive spikes were studied retrospectively in 2,026 Chinese patients, ranging in age from 1 to 18 years. All of them were the first-evaluation patients of Pediatric Neurology Clinics, National Taiwan University Hospital, each had had through EEG examinations (including waking and natural sleep records) and detailed medical records. The major findings of the present study are: (1) The overall incidence of the 14 and 6 Hz positive spikes in the series was 2.52% (51/2,026), and that in the age subgroup 1-5 years was significantly lower than those in the subgroups 6-10 years (p less than 0.0001) and 11-15 years (p less than 0.01). (2) 38 out of 51 cases (74.5%) with 14 and 6 Hz positive spikes presented normal EEG background activity. (3) 7 out of 51 cases (13.7%) had coincided negative spikes in frontal areas, and 12 out of 51 cases (23.5%) were associated with other focal or generalized paroxysmal discharges. (4) From the analysis of the clinical manifestations in the 51 cases with the 14 and 6 Hz positive spikes, the episodic attacks of headache, abdominal pain or other autonomic symptoms were most common (49%, 25/51 cases). Of the 25 cases, 19 cases (37.2%, 19/51 cases) were finally diagnosed as autonomic seizure or abdominal epilepsy and 3 cases were diagnosed as migraine. 3 of 10 cases with convulsive seizure or complex partial seizure were associated with autonomic symptom. (5) The etiology in 36 out of 51 cases (70.6%) remained unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

[Wilson disease presenting as fulminant hepatic failure, acute hemolytic anemia and renal failure: report of one case]

Wilson disease presenting as fulminant hepatic failure, severe hemolysis and renal failure is rare in the literature. A ten-year-old boy--complaining of abdominal pain, jaundice, tea-colored urine, and anemia was admitted to this hospital; examination showed Kayser-Fleischer rings, anemia associated with hemolysis, mildly elevated serum transaminases, extremely elevated bilirubin levels, low serum ceruloplasmin level, slightly elevated serum copper, excessive 24-hour urine copper excretion, and severe renal function insufficiencies. Under the impression of Wilson disease with fulminant hepatic failure, the patient was treated by oral D-penicillamine 1 gm per day, intravenous zinc sulphate (about 8 mg per day elemental zinc), and given other supportive treatment. Unfortunately, the patient died of hepatic failure complicated with septic shock 21 days after the onset of symptoms. Autopsy found liver copper content was 586.92 ug/gm dry weight and kidney copper content: 300.19 ug/gm dry weight, abnormally high as compared with normal tissue. A review of the literature led to conclusion that the best treatment for Wilson fulminant hepatic failure is liver transplantation.

Instrumental neutron activation analysis of gallstones

Four kinds of gallstones from 40 patients have been analyzed for the presence of a total of 18 elements by instrumental neutron activation analysis. Of these elements, Ca, Mg, Fe, Co, Zn, Na, and Cl are found in the core of all types of stones. The differences in elemental composition of the various types of stones as well as the differences in the cross-sectional layers of stones are statistically evaluated.

Determination of major, minor and trace elements in urinary stones by neutron activation analysis

In five kinds of human urinary stones 18 elements have been identified by instrumental neutron activation analysis (INAA). From the results it may be concluded that calcium is the most important initiating cation, magnesium is the second most significant one, and Na, Cl, Sr, Zn, Fe, Br and Co may also play an important role in the stone formation. The results indicate also that ions like Ca, Br and Cu are easily incorporated into the nucleus to form a urate stone; Mg and Sr, into the nucleus to form a magnesium ammonium phosphate stone; and Zn, into the nucleus to form a calcium oxalate combined with apatite stone. The differences in elemental composition among the different kinds of stones as well as across the layers of stones are statistically evaluated.

Sorption of low-level radwaste by Spirulina

The feasibility of using spirulina as adsorbent for the treatment of low-level liquid radwaste is studied. The experimental results indicate that the sorption capacity of spirulina is good for the di- and trivalent metallic ions at pH 3-7, but rather poor for the mono-valent metallic ions and non-metallic ions. Some factors affecting metal ion uptake by spirulina such as the content of detergent, sodium ion in liquid radwaste and the stability of spirulina under gamma irradiation were also investigated.

Radiolysis of CoIII-EDTA solution by charged particles through 6Li(n,a)3H reaction

This experiment was to study the radiolysis of CoIII-EDTA solution in 0.8N H2SO4 saturated with air by charged particles produced through 6Li(n,a)3H reaction. The experimental results show that the G(-CoIII-EDTA) decreases as the absorbed dose rate increases. For the same absorbed dose rate, the values of G(-CoIII-EDTA) are practically independent of absorbed dose. The effects of concentration and temperature are also studied.

Determination of trace amounts of mercury in water by neutron activation analysis with lubricating base oil as extractant

This paper deals with a convenient method in the determination of trace amounts of mercury in water. After being irradiated with neutrons, water sample was treated with 7.0M HCIO4 solution and mercury was extracted with lubricating base oil. In such a simple operation, the sensitivity can reach 10(-8)g Hg/4ml H2O.