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.

Dosimetric Impact of Radiolucent Carbon Fiber Hardware for Post-Operative Spine Stereotactic Body Radiation Therapy

PURPOSE/OBJECTIVE(S)

The spine is the most common site of osseous metastases. In the non-operative setting, there is growing support for stereotactic body radiation therapy (SBRT) over conventional radiation therapy for improved pain relief and local control. Hybrid therapy consisting of separation surgery and post-operative SBRT is considered in patients with biomechanical instability and epidural cord compression. Surgery traditionally requires titanium (Ti) implants, which introduce artifacts on post-operative imaging in addition to increased uncertainty and beam attenuation. Use of radiolucent carbon fiber reinforced polyetheretherketone (CFR-PEEK) hardware has been shown to provide safe and comparable surgical outcomes as compared to Ti. Our primary objective is to assess the dosimetric impact of Ti versus carbon fiber implants in spine SBRT.

MATERIALS/METHODS

Single institution retrospective series of post-operative spine SBRT from 2019-2020. Re-irradiation cases were excluded. The electronic medical record and treatment planning systems (TPS) were queried. Dosimetric analyses compared original Ti plans with reoptimized plans, replacing Ti hardware electronic density with carbon fiber. Maintaining clinical goals, dose calculations were performed in a treatment planning system using a collapsed cone algorithm. All treatments used step and shoot intensity modulated radiation therapy to avoid beam angles with significant metal along the beam path. Metallic artifacts were contoured and assigned the appropriate tissue density. A D'Agostino-Pearson test was used to assess data for normality. We used paired Student's t-tests to compare three dosimetric outcomes in the setting of Ti and carbon fiber implants. Planning target volume (PTV) coverage was represented by the volume receiving at least the prescribed dose (%), the maximum point dose (dmax, cGy) to the spinal cord planning risk volume (PRV, 2 mm margin), and the overall hot spot intensity (plan dmax).

RESULTS

A series of 14 consecutive SBRT cases were evaluated (dose 27-30 Gy in 3-5 fractions). All dosimetric outcomes were normally distributed (p>0.05). We found a statistically significant difference in PTV coverage between the original SBRT treatment plans with Ti hardware (mean 85.1 ± 7.9%) and reoptimized carbon fiber hardware (87.3 ± 6.6%; p = 0.002). There was no significant difference in mean spinal cord PRV dmax between Ti and carbon fiber plans (1846 ± 483 cGy vs. 1842 ± 495 cGy; p>0.05). We observed a nonsignificant increase in mean overall dmax from 3932 ± 416 cGy in the Ti cohort to 4111 ± 906 cGy in the carbon fiber cohort (p>0.05).

CONCLUSION

Carbon fiber implants provide a significant increase in SBRT target coverage, without impacting the overall plan and spinal cord PRV dmax in this retrospective series. In addition to improved post-operative imaging and reduced uncertainty, carbon fiber hardware may offer dosimetric advantages as compared to traditional Ti spinal implants, and warrants further investigation in a larger cohort.

Craniospinal Irradiation for CNS Leukemia: Rates of Response and Durability of CNS Control

PURPOSE/OBJECTIVE(S)

Craniospinal irradiation (CSI) is used in the management of leukemia patients with central-nervous-system (CNS) involvement, though the data on response and local control are limited. Given the radioresponsiveness of leukemia, we hypothesized that response to CSI would be high, but CNS control would be influenced by control of systemic disease.

MATERIALS/METHODS

This retrospective, single-institution analysis included consecutive pediatric and adult patients between 2009-2021 with leukemia that underwent CSI for CNS involvement, defined as presence of blasts (i.e., >0%) on CSF flow cytometry. Endpoints included CNS response rate (RR), CNS local recurrence (LR), progression-free survival (PFS), and overall survival (OS), which were estimated from start of CSI. The probability of CNS LR was summarized using a cumulative incidence estimate, where death without LR was considered a competing risk. The probabilities of OS and PFS were obtained using Kaplan-Meier estimates.

RESULTS

Among the 39 eligible patients (43% AML, 49% ALL, 8% blast-phase CML), most were male (59%). All had CSF confirmation of disease. Median age at CSI was 31 years (range 7-67). CSI (protons 54%, photons 46%) was utilized early within the CNS disease course (median 0 CNS relapses prior to CSI). Twenty-five patients (64%) received CSI immediately prior to a stem-cell transplant (SCT), of which 21 (84%) had TBI conditioning to a median dose of 12 Gy (range 2-13.2). Patients treated with CSI alone received a higher CSI dose (median 18 Gy; range 10.8-24) than those treated with SCT consolidation (median 12 Gy; range 10.8-24). Fifteen patients had CSF-positive disease immediately prior to CSI; all 14 of those assessed for response (RR 100%) had confirmed clearance of blasts at a median of 23 days (range 7-197) from CSI start. With a median follow-up of 48 months (range 0.4-123) for survivors, 2-year PFS and OS estimates were 32% and 43%, respectively. Only 5 CNS relapses were noted (2-year CNS LR of 14%). All CNS relapses either occurred after (n = 4) or concurrently (n = 1) with a systemic relapse. In Cox regression univariate models, age, sex, time to CNS disease, positive CSF immediately prior to CSI, and SCT did not show demonstrable evidence of association with CNS LR. However, systemic relapse after CSI (HR 5.9, 95% CI 2.5-13.8, P<0.0001) and systemic disease at the time of CSI (HR 3.9, 95% CI 1.6-9.5, P = 0.003) were associated with higher risk of CNS LR. No grade-3+ acute toxicity was seen during CSI.

CONCLUSION

CSI is a well-tolerated and effective treatment option for patients with CNS leukemia. Though CNS local recurrence was modest, there was a high risk of systemic relapse and/or death. Control of systemic disease, both before and after CSI, may be important for CNS local control, and raises consideration that CNS recurrence may reflect reseeding from the systemic space.

5-Year Renal Function Outcomes after SABR for Primary Renal Cell Carcinoma: A Report from the International Radiosurgery Oncology Consortium of the Kidney (IROCK)

PURPOSE/OBJECTIVE(S)

Renal cell carcinoma (RCC) presents uncommonly in patients with a congenital solitary kidney or prior contralateral nephrectomy. The objective of this study was to compare renal function outcomes of stereotactic ablative body radiotherapy (SABR) in patients with solitary vs. bilateral kidneys.

MATERIALS/METHODS

Patients with primary RCC with ≥2 years of follow-up at 12 participating International Radiosurgery Consortium for Kidney (IROCK) institutions were included. Patients with upper tract urothelial carcinoma or metastatic disease were excluded. Renal function was measured by estimated glomerular filtration rate (eGFR). For patients where eGFR was not recorded, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation was used to estimate eGFR based on known creatinine. Baseline characteristics and renal function outcomes were compared between solitary vs. bilateral kidneys. Multivariable logistic regression was used to identify factors predictive of eGFR decline ≥ 15 mL/min and any eGFR increase evaluated at 1-year post-SABR.

RESULTS

One hundred and ninety patients with solitary (n = 56) or bilateral kidneys (n = 134) underwent SABR and were followed for a median of 5.0 years (IQR: 3.4-6.8). Pre-SABR eGFR (mean ± SD) was similar in patients with solitary (61.1 ± 23.2 mL/min) vs. bilateral kidneys (58.0 ± 22.3 mL/min, p = 0.324). Mean tumor size was 3.70 ± 1.40 cm in solitary and 4.35 ± 2.50 cm in bilateral kidneys (p = 0.026). After SABR, an initial compensatory increase in eGFR was observed in both cohorts (22.7% solitary and 17.7% bilateral at 1 year). This compensatory increase persisted in patients with bilateral but not a solitary kidney (10.3% vs. 0% at 3-years and 21.1% vs. 0% at 5-years, respectively). At 5-years post-SABR, eGFR decreased by -14.5 ± 7.6 in solitary and -13.3 ± 15.9 mL/min in bilateral kidneys (p = 0.665). At all timepoints assessed, there were no significant differences in eGFR decline between solitary vs. bilateral cohorts (all p > 0.05). There were also no significant differences in post-SABR end-stage renal disease (7.1% vs. 6.7%) or dialysis (3.6% vs. 3.7%) in solitary vs. bilateral, respectively. Multivariable analysis demonstrated that increasing tumor size (OR per 1 cm: 1.57; 95% CI: 1.14-2.16, p = 0.006) and baseline eGFR (OR per 10 mL/min: 1.30; 95% CI: 1.02-1.66, p = 0.034) was more likely to be associated with eGFR decline ≥ 15 mL/min. There was no significant association between solitary vs. bilateral kidney and eGFR decline (OR: 1.22; 95% CI: 0.45-3.34, p = 0.693).

CONCLUSION

There was no observed difference between renal function outcomes in patients with a solitary vs. bilateral kidneys. While larger tumor size may increase the risk of eGFR decline post-SABR, treatment of a solitary kidney does not appear to increase the risk of renal dysfunction long-term.

Survey of current practices from an international task force for gynecological stereotactic ablative radiotherapy

Background

Stereotactic Ablative Radiotherapy (SABR) is an effective treatment that improves local control for many tumours. However, the role of SABR in gynecological cancers (GYN) has not been well-established. We hypothesize that there exists considerable variation in GYN-SABR practice and technique. The goal of this study is to describe clinical and technical factors in utilization of GYN-SABR among 11 experienced radiation oncologists.

Materials and methods

A 63 question survey on GYN-SABR was sent to 11 radiation oncologists (5 countries) who have published original research, conducted trials or have an established program at their institutions. Responses were combined and analyzed at a central institution.

Results

Most respondents indicated that salvage therapy (non-irradiated or re-irradiated field) for nodal (81%) and primary recurrent disease (91%) could be considered standard options for SABR in the setting of inability to administer brachytherapy. All other indications should be considered on clinical trials. Most would not offer SABR as a boost in primary treatment off-trial without absolute contraindications to brachytherapy. Multi-modality imaging is often (91%) used for planning including PET, CT contrast and MRI. There is a wide variation for OAR tolerances however small bowel is considered the dose-limiting structure for most experts (91%). Fractionation schedules range from 3 to 6 fractions for nodal/primary definitive and boost SABR.

Conclusions

Although SABR has become increasingly standard in other oncology disease sites, there remains a wide variation in both clinical and technical factors when treating GYN cancers. Nodal and recurrent disease is considered a potential indication for SABR whereas other indications should be offered on clinical trials. This study summarizes SABR practices among GYN radiation oncologists while further studies are needed to establish consensus guidelines for GYN-SABR treatment.

Abstract P4-16-10: Bone health in young women with breast cancer

Introduction:

There are limited data and consensus regarding bone mineral density (BMD) monitoring, and management of bone loss in younger women with breast cancer (BC). Adjuvant endocrine therapy for estrogen receptor positive (ER+) BC may include ovarian function suppression (OFS) plus use of aromatase inhibitors (AIs) for 5-10 years, both of which contribute to bone loss. The WHO risk prediction tool FRAX does not include BC or AI use as independent risk factors in its calculation thus underestimating risk of fracture. This study aims to evaluate current screening and management of bone health in young women with BC.

Methods:

A retrospective, IRB-approved chart review was performed in consecutive women ≤40 with BC diagnosed at Loyola University Chicago Medical Center between 01/01/2015 and 12/13/17. Demographic data, BC treatment, and factors contributing to secondary causes of bone loss were collected through 4/1/18. A descriptive analysis included summary values for all categorical and continuous risk factors.

Results:

BC ≤40yrs was identified in 136 women; 18 were excluded due to missing data. The analysis was performed on 118 patients (pts). Mean pt age was 34.6 yrs (SD 4.7). Stage at diagnosis included: stage 0 = 9 (7.6%), stage 1 = 26 (22%), stage 2 = 44 (37.3%), stage 3 = 23 (19.5%), stage 4 = 7 (5.9%), unknown = 9 (7.6%). Seventy-nine (67%) had ER+ BC; 32 (27.1%) had HER2-positive disease. The majority of pts (101, 85.6%) received chemotherapy in their treatment plan. Menopause was documented in 69 (59.0%) pts. Goserelin was used in 31 pts (44.9%), oophorectomy in 17 (24.6%), both in 5 (7.2%). Tamoxifen was used in 44 (55.7%) ER+ pts; 34 (43.0%) received an AI, and 18 (22.8%) received sequential tamoxifen and AI. 25 Hydroxy-Vitamin D (25 OHD) levels were checked in 61 (51.7%); 43 (70.5%) had levels &lt;30 ng/ml; 24 (55.8%) received vitamin (vit) D supplementation. There was no difference in the 25 OHD in pre- and post-menopausal women (p=0.64). Pts with vit D deficiency had a median BMI of 26.8 vs 23.8 in those with sufficient vit D levels (exact p=.049). Secondary diagnoses contributing to low BMD were identified in 14 (11.8%). Dual energy xray absorptiometry (DXA) scans were checked in 23 pts (19.7%), 18 of whom were post-menopausal. At the femur, 0 pts had a z-score (age-matched standard deviation) of ≤-2.0, 9 pts (39.1%) had a score between 0 to -2.0. At the lumbar spine, 1 pt (4.3%) had a z-score ≤-2.0, 9 pts (39.1%) had a z-score between 0 to -2.0. No T-scores were in the osteoporosis range; 11 pts had T-scores at both femur and lumbar spine in the osteopenia range. The median 10 yr probability of a major osteoporotic fracture (FRAX score) was 1.9% (1.6-2.7%); the median 10 yr probability for hip fracture was 0.1% (0.10-0.20%). There were no differences in FRAX scores between pre- and post-menopausal women. No fractures were reported in the time period studied. Anti-resorptive therapy was used only in patients with metastatic bone disease.

Conclusions:

25 OHD and DXA scans are not routinely checked in younger women diagnosed with BC. Vit D deficiency and evidence of bone loss is prevalent in those pts who do undergo testing. Further research and guidelines are necessary to address management of bone health in young women with BC to minimize future fracture risk and morbidity.

Citation Format: Wendell KB, Nadeem S, Martin B, Camacho PM, Albain KS, Robinson P, Lo SS. Bone health in young women with breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-16-10.

Imaging nano-objects by linear and nonlinear optical absorption microscopies

Absorption based microscopy measurements are emerging as important tools for studying nanomaterials. This review discusses the three most common techniques for performing these experiments: transient absorption microscopy, photothermal heterodyne imaging, and spatial modulation spectroscopy. The focus is on the application of these techniques to imaging and detection, using examples taken from the authors' laboratory. The advantages and disadvantages of the three methods are discussed, with an emphasis on the unique information that can be obtained from these experiments, in comparison to conventional emission or scattering based microscopy experiments.

Time-Resolved Studies of the Acoustic Vibrational Modes of Metal and Semiconductor Nano-objects

Over the past decade, there have been a number of transient absorption studies of the acoustic vibrational modes of metal and semiconductor nanoparticles. This Perspective provides an overview of this work. The way that the frequencies of the observed modes depend on the size and shape of the particles is described, along with their damping. Future research directions are also discussed, especially how these measurements provide information about the way nano-objects interact with their environment.

Detection of single gold nanoparticles using spatial modulation spectroscopy implemented with a galvo-scanning mirror system

The optical extinction of single nanoparticles can be sensitively detected by spatial modulation spectroscopy (SMS), where the particle is moved in and out of a tightly focused laser beam with a piezo-device. Here we show that high sensitivity can be obtained by modulating the beam with a galvo-mirror system, rather than by moving the sample. This work demonstrates an inexpensive method for making a SMS microscope, and shows how an existing laser scanning microscope can be adapted for SMS measurements. The galvo-mirror technique also allows SMS measurements to be performed in a liquid, which is difficult to do with piezo-modulation.

Physics. Spectroscopy beyond the single-particle limit

Ultrafast x-ray diffraction studies reveal the lattice vibrations of single gold nanoparticles. [Also see Report by Clark et al. ]

Imaging the extent of plasmon excitation in Au nanowires using pump-probe microscopy

Knowledge of how energy and charge carriers move in nanoscale systems is essential for engineering efficient devices. In this Letter, we demonstrate a technique to directly image dynamics in nanostructures based on laser scanning transient absorption microscopy, which provides near diffraction-limited spatial resolution and ultrafast time resolution. The capabilities of the technique are demonstrated by experiments on propagating surface plasmon polariton modes of Au nanowires, although these measurements can be used to study a variety of fluorescent and nonfluorescent systems.

Abstract P1-12-04: Carboplatin, nab-paclitaxel and bevacizumab as first-line treatment for metastatic breast cancer

Background: Bevacizumab added to weekly paclitaxel resulted in improved progression free survival (PFS) and objective response rates (ORR) compared to weekly paclitaxel alone. Nab-paclitaxel and the platins are active in MBC. We conducted an efficacy and safety study of carboplatin, nab-paclitaxel and bevacizumab.

Methods: A phase II open label prospective multi-site study enrolled patients (pts) who had measurable MBC according to RECIST 1.1 criteria and no prior chemotherapy for advanced disease. The primary endpoint was PFS with secondary endpoints of overall survival (OS), ORR, and safety. Pts initially received carboplatin AUC 6 day 1, 22,43, plus weekly nab-paclitaxel 100mg/m2 and bevacizumab 15mg/m2 day 1,22,43 of a 56 day cycle. This was later changed to carboplatin AUC 6 day 1, nab-paclitaxel 100mg/m2 day 1,8,15, and bevacizumab 10mg/m2 day 1,15 of a 28 day cycle. Thirty-two pts were required to detect an increase in median PFS from 6.7 to 10.5 mo with 80% power based on a one-sided p = 0.05. Kaplan–Meier analyses estimated PFS and OS. The log rank test was used for the comparison of survival curves between pts with triple negative MBC (TNBC) and pts with non-TNBC.

Results: Thirty-two pts were enrolled between 2/2008 and 11/2011 by 1 academic and 5 community oncology practices. Two pts were ineligible due to non-measurable disease and not included in the response analyses. The median age was 58 years (range 35–81), 22 pts (69%) had an ECOG PS 0, 9 (28%) had a PS 1, 1 (3%) PS 2. Twenty-four (75%) pts had ER+ disease, 7 (22%) had TNBC, 1 (3%) had ER-HER2+ disease not eligible for trastuzumab-based therapy. Metastatic sites were bone (26%), liver (18%), loco-regional (16%), and lung (12%). One pt (3%) had bone and loco-regional disease only, 19 (59%) had visceral dominant disease. The median number of weeks on treatment was 28.9 (range 5–131). The median PFS in all pts was 13.6 months (mo) (95% CI 11.2–21.9), with a median OS of 26.8 mo (95% CI 13.3–41.2). The ORR (2 CR and 18 PR) was 66.7% (CI 47.2–82.7). There also were 6 (20%) unconfirmed PR and 3 (10%) stable disease, resulting in a clinical benefit rate of 96.7% (CI 82.78–99.92). There was no significant difference in PFS (median 13.6 vs 16.1mo, p = 0.37) or OS (median 13.6 vs 26.8mo, p = 0.32) in pts with TNBC versus non-TNBC disease. The most common toxicities of any grade (gr) include neutropenia and thrombocytopenia in 24 pts (75%) each, leukopenia and fatigue in 17 pts (53%) each, anemia in 15 (47%), and neuropathy in 10 (31%). Gr 4 neutropenia was seen in 7 pts (22%) without febrile neutropenia, and gr 4 thrombocytopenia occurred in 6 (19%). There were no pts with gr 4 sensory neuropathy. All pts required chemotherapy dose delays, 15 (47%) had chemotherapy dose reductions.

Conclusions: The carboplatin, nab-paclitaxel and bevacizumab combination is highly effective with good tolerance in first line MBC. As the role of anti-angiogenic therapy in first line metastatic breast cancer is being clarified, this would be an attractive regimen to test in the (neo)adjuvant setting and together with novel molecular targeted agents.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-12-04.

Abstract PD10-02: Metabolic syndrome and recurrence within the 21-gene recurrence score assay risk categories in lymph node negative breast cancer

Background: The incidence of the metabolic syndrome (MS) has been increasing in the United States and elsewhere. The interaction of MS with breast cancer (BC) incidence, tumor biology and outcomes are under study. We hypothesized that the presence of MS would predict BC recurrence to a variable degree across the diverse BC biology as defined by the risk categories of the 21-gene recurrence score (RS) assay.

Patients and Methods: We studied consecutive patients (pts) with newly diagnosed, estrogen receptor (ER) positive, lymph node (LN) negative BC treated in our institution between 2006–2011 who had a 21-gene RS assay done on their tumors. All pts were treated with standard systemic and local therapy. The electronic medical record was queried for key diagnoses including MS and its constituent parts. The WHO definition was used to categorize pts as having MS defined as diabetes mellitus (DM) or glucose intolerance, plus at least 2 of the following: hypertension (HTN), dyslipidemia (HL), central obesity and microalbuminemia. Tumor characteristics including Ki67 index, grade, tumor size, HER2/neu status; and pt characteristics including age, race, menopausal status, body mass index were recorded. The association of MS and the tumor and patient characteristics with the RS tertiles of low, intermediate and high risk was analyzed.

Results: We identified 332 pts, median age 62 years, of whom 88 (27%) had MS. There was no significant association between the MS and any of the patient or tumor variables including the 21-gene RS assay, except for race (p = 0.004). Eleven of 21 (52%) African-American women had MS, 68 of 284 (24%) Caucasian women had MS, and 9 of 21 (43%) others including Hispanic and Asian women had MS. However, there was a significant association between recurrence and MS (p = 0.0002) independent of other factors. Of the 21 pts who recurred, 13 (61.9%) had MS. There was an association of recurrence and MS within RS tertiles. For pts with low risk scores, 7/44 (15.9%) with MS vs. 1/126 (0.79%) without MS had recurrence (p = 0.0003). For pts with intermediate risk scores, 5/30 (16.67%) with MS vs. 4/83 (4.82%) without MS had recurrence (p = 0.05). For patients with high risk scores, 1/9 (11.11%) with MS vs. 2/15 (13.33%) without MS had recurrence (p = 1).

Conclusion: MS is an independent risk factor for BC recurrence among women with LN negative, ER positive BC treated with standard adjuvant therapy. There is a striking impact of MS on recurrence in pts with tumor biologies defined by low (and to a lesser degree) intermediate risk 21-gene RS assay scores. However, there is no difference in recurrence risk by MS among those pts with high RS. This implies that interventions directed at modifying MS in newly diagnosed pts with early BC may potentially favorably impact survival in those with specific tumor biologies as defined by multigene assays. Thus, long-term prospective studies should be conducted to further evaluate both the short and long term effects of MS on BC outcomes.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD10-02.

Ultrasound-guided thrombin injection for pseudoaneurysms: a case series at a local hospital

Post-catheterization pseudoaneurysms are increasingly prevalent due to widespread use of endovascular procedures. Ultrasound-guided thrombin injection has emerged as a treatment of choice for these pseudoaneurysms. We review our experience performing this procedure for a series of cases from 2007 to 2010 with different clinical manifestations at a single hospital in Hong Kong. We achieved a high technical success rate with no complications.

Charge carrier trapping and acoustic phonon modes in single CdTe nanowires

Semiconductor nanostructures produced by wet chemical synthesis are extremely heterogeneous, which makes single particle techniques a useful way to interrogate their properties. In this paper the ultrafast dynamics of single CdTe nanowires are studied by transient absorption microscopy. The wires have lengths of several micrometers and lateral dimensions on the order of 30 nm. The transient absorption traces show very fast decays, which are assigned to charge carrier trapping into surface defects. The time constants vary for different wires due to differences in the energetics and/or density of surface trap sites. Measurements performed at the band edge compared to the near-IR give slightly different time constants, implying that the dynamics for electron and hole trapping are different. The rate of charge carrier trapping was observed to slow down at high carrier densities, which was attributed to trap-state filling. Modulations due to the fundamental and first overtone of the acoustic breathing mode were also observed in the transient absorption traces. The quality factors for these modes were similar to those measured for metal nanostructures, and indicate a complex interaction with the environment.