Abstract P4-02-07: Preoperative assessment of breast cancer survival using ultrasound diameter and shear wave elastography

This abstract was not presented at the symposium.

Abstract PD3-04: Which measure of the interim changes in breast tumoral volume at breast MRI in response to neoadjuvant chemotherapy best predicts final pathological response?

BACKGROUND: Interim changes in breast tumour volume at magnetic resonance imaging (MRI) can predict ultimate response to neoadjuvant chemotherapy (NAC), but there is little data on the best measure of volumetric change.

PURPOSE: To assess whether changes in measurements of semi-automated enhancing tumour volume (ETV) or fully automated functional tumour volume (FTV) between baseline and interim contrast-enhanced MRI are equivalent in predicting ultimate pathological response to neoadjuvant chemotherapy (NAC) for primary breast cancer, assessed using the residual cancer burden (RCB) score.

MATERIALS & METHODS: 78 patients undergoing treatment with NAC for primary breast cancer underwent contrast-enhanced MRI on a 1.5T or 3.0T MRI scanner using a dedicated bilateral breast coil before and after two or three cycles of NAC. Image analysis was performed using either semi-automated, user-defined thresholding (ITK-Snap; ETV) or fully-automated (Siemens SyngoVia BreVis; FTV) approaches. For ETV, the two-minute post-contrast subtracted volumes were analysed, with enhancing pixels thresholded to define tumour volume. FTV was measured using a manufacturer default setting of 50% enhancement threshold, relative to pre-contrast signal intensity, to define tumour volume. ETV intra-observer reproducibility was assessed by repeat analysis one month after initial analysis and a second observer also repeated the measure. Coefficient of reproducibility (CoR) and intraclass correlation coefficents (ICC) were calculated for intra- and inter-observer repeatability.

ETV and FTV percentage reduction between baseline and interim examinations was compared with final pathological response, as assessed using the residual cancer burden (RCB) score on resected cancer specimens.

Correlation of the two volumetric measures was performed using a Pearson Intra-class Correlation Coefficient (ICC) and pair-wise comparisons of ETV and FTV changes between RCB groups carried out using a Mann-Whitney U test. All statistical assessment was performed using SPSS, v21, with p<0.05 considered significant.

RESULTS: There was significant correlation between ETV and FTV (ICC= 0.744, p<0.05). Intra and inter observer reproducibility for ETV was excellent, with ICC 0.940 and 0.861 respectively and corresponding CoRs of 11.6% and 14.8%.

Average percentage reductions in ETV for each pathological response category were: pCR 96.4% (n=12), RCB-I 66.6% (n=10), RCB-II 62.9% (n=39) and RCB-III 27.3% (n=17). Corresponding values for FTV were 88.8%, 70.6%, 54.6% and 20.8%.

Significant differences in percentage ETV changes were found for pCR vs. RCB-I (p<0.008), II (p<0.001) & III (p<0.001) and RCB-II vs. RCB-III (p<0.001). For FTV, significant differences were measured only for pCR vs. RCB-II & III (p<0.001).

CONCLUSION: changes in the semi-automated ETV measuement between baseline and interim MRI may provide more useful predictive information on final pathological response to NAC than FTV, as the changes are better able to discriminate between pCR and minimal residual disease (RCB-I). The ability to confidently predict pCR versus all other residual disease categories could facilitate planning of enhanced approaches to surgical management.

Citation Format: Thompson AM, Vinnicombe SJ, Waugh SA, Purdie CA, Evans AJ, Brunton T, Fuller-Pace FV. Which measure of the interim changes in breast tumoral volume at breast MRI in response to neoadjuvant chemotherapy best predicts final pathological response? [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr PD3-04.

Abstract P1-11-04: Looking beyond the margins: Economic costs and complications associated with repeated breast-conserving surgeries

Background: Although considerable attention has been drawn to the problem of repeat breast-conserving surgery (BCS), the costs and complications due to these additional operations are not well-characterized. In this work, a retrospective review of insurance claims data for BCS patients was performed to assess complications and economic outcomes.

Methods: Private claims data were analyzed for 9,837 women undergoing BCS for breast carcinoma between January 2010 and December 2013. Patients enrolled in insurance plans in IL, TX, NM, and OK were included. Patients undergoing a second open breast surgery (mastectomy or BCS) within 90 days of the initial BCS were classified as having a repeat surgery. Complications were identified via a set of 8 CPT and 25 ICD9 diagnosis and procedure codes related to breast cancer treatment. The analysis included these complications and the total cost of all allowed healthcare claims within two years following diagnosis.

Results: 7,555/9,837 patients (77% ±0.8%, 95% confidence interval) had one BCS operation, and 2,282 patients (23% ±0.8%) had at least one repeat surgery. The mean patient age was 53 years. Women who underwent an additional operation waited an average of 24 days for the procedure.

The mean two-year total costs for patients undergoing a single BCS was $89,016 (±$1,884), and the cost for patients undergoing a repeat breast surgery was $105,088 (±$3,680; p < 0.0001), $100,637 (±$4,219) for a second BCS and $115,292 (±$7,259) for subsequent mastectomy. The mean added cost due to a repeat surgery was $16,072.

The percentage of patients experiencing at least one complication was 23.6% (±1.0%) for those undergoing one BCS only and 34.8% (±2.0%) for those undergoing a repeat operation (p < 0.0001). Patients undergoing repeated surgery were 88% more likely to experience multiple complications (5.5% ±0.5% vs. 10.4% ±1.3%) and nearly three times as likely to experience fat necrosis (2.5% ±0.4% vs. 7.2% ±1.1%). Infection, hematoma/seroma, and breast pain were the most common complications for patients who did not undergo a repeated surgery (9.9% ±0.7%, 8.7% ±0.6%, 6.9% ±0.6%). For patients undergoing a repeated surgery, infection, hematoma/seroma, and fat necrosis were the most common complications (15.3% ±1.5%, 13.9% ±1.4%, 7.2% ±1.1%).

Conclusions: For the 23% of women undergoing a second operation after BCS, complications were 48% more common, and the mean total cost of surgery was $16,072 more, demonstrating statistically-significant evidence of a patient-centered and fiscal imperative to reduce reoperations in BCS for breast cancer.Background: Although considerable attention has been drawn to the problem of repeat breast-conserving surgery (BCS), the costs and complications due to these additional operations are not well-characterized. In this work, a retrospective review of insurance claims data for BCS patients was performed to assess complications and economic outcomes.

Methods: Private claims data were analyzed for 9,837 women undergoing BCS for breast carcinoma between January 2010 and December 2013. Patients enrolled in insurance plans in IL, TX, NM, and OK were included. Patients undergoing a second open breast surgery (mastectomy or BCS) within 90 days of the initial BCS were classified as having a repeat surgery. Complications were identified via a set of 8 CPT and 25 ICD9 diagnosis and procedure codes related to breast cancer treatment. The analysis included these complications and the total cost of all allowed healthcare claims within two years following diagnosis.

Results: 7,555/9,837 patients (77% ±0.8%, 95% confidence interval) had one BCS operation, and 2,282 patients (23% ±0.8%) had at least one repeat surgery. The mean patient age was 53 years. Women who underwent an additional operation waited an average of 24 days for the procedure.

The mean two-year total costs for patients undergoing a single BCS was $89,016 (±$1,884), and the cost for patients undergoing a repeat breast surgery was $105,088 (±$3,680; p < 0.0001), $100,637 (±$4,219) for a second BCS and $115,292 (±$7,259) for subsequent mastectomy. The mean added cost due to a repeat surgery was $16,072.

The percentage of patients experiencing at least one complication was 23.6% (±1.0%) for those undergoing one BCS only and 34.8% (±2.0%) for those undergoing a repeat operation (p < 0.0001). Patients undergoing repeated surgery were 88% more likely to experience multiple complications (5.5% ±0.5% vs. 10.4% ±1.3%) and nearly three times as likely to experience fat necrosis (2.5% ±0.4% vs. 7.2% ±1.1%). Infection, hematoma/seroma, and breast pain were the most common complications for patients who did not undergo a repeated surgery (9.9% ±0.7%, 8.7% ±0.6%, 6.9% ±0.6%). For patients undergoing a repeated surgery, infection, hematoma/seroma, and fat necrosis were the most common complications (15.3% ±1.5%, 13.9% ±1.4%, 7.2% ±1.1%).

The impact of repeated breast-conserving surgeries BCS, No RepeatRepeat BCSConvert to MastectomyPatients76.8% (7,555)16.2% (1,589)7.0% (693)Mean Two-Year Cost Per Patient$89,016$100,637$115,292Patients with any Complication(s)23.6% (1,783)32.5% (516)40.3% (279)Patients with Infection9.9% (746)14.0% (222)18.3% (127)Patients with Hematoma/Seroma8.7% (655)12.8% (203)16.6% (115)Patients with Breast Pain6.9% (525)7.0% (111)6.1% (42)Patients with Fat Necrosis2.5% (187)7.6% (120)6.5% (45)

Conclusions: For the 23% of women undergoing a second operation after BCS, complications were 48% more common, and the mean total cost of surgery was $16,072 more, demonstrating statistically-significant evidence of a patient-centered and fiscal imperative to reduce reoperations in BCS for breast cancer.

Citation Format: Metcalf LN, Zysk AM, Underwood HR, Edelman G, Vu L, Cittadine AJ, Hyer KB, Thompson AM. Looking beyond the margins: Economic costs and complications associated with repeated breast-conserving surgeries [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-11-04.

Tropospheric ozonesonde profiles at long-term U.S. monitoring sites: 2. Links between Trinidad Head, CA, profile clusters and inland surface ozone measurements

Much attention has been focused on the transport of ozone (O₃) to the Western U.S., particularly given the latest revision of the National Ambient Air Quality Standard (NAAQS) to 70 parts per billion by volume (ppbv) of O₃. This makes defining a "background" O₃ amount essential so that the effects of stratosphere-to-troposphere exchange and pollution transport to this region can be quantified. To evaluate free-tropospheric and surface O₃ in the Western U.S., we use self-organizing maps to cluster 18 years of ozonesonde profiles (940 samples) from Trinidad Head, CA. Two of nine O₃ mixing ratio profile clusters exhibit thin laminae of high O₃ above Trinidad Head. A third, consisting of background (~20 - 40 ppbv) O₃, occurs in ~10% of profiles. The high O₃ layers are located between 1 and 4 km amsl, and reside above a subsidence inversion associated with a northern location of the semi-permanent Pacific subtropical high. Several ancillary data sets are examined to identify the high O₃ sources (reanalyses, trajectories, remotely-sensed carbon monoxide), but distinguishing chemical and stratospheric influences of the elevated O₃ is difficult. There is marked and long-lasting impact of the elevated tropospheric O₃ on high-altitude surface O₃ monitors at Lassen Volcanic and Yosemite National Parks, and Truckee, CA. Days corresponding to the high O₃ clusters exhibit hourly surface O₃ anomalies of +5 - 10 ppbv compared to a climatology; the anomalies can last up to four days. The profile and surface O₃ links demonstrate the importance of regular ozonesonde profiling at Trinidad Head.

Tropospheric ozone change from 1980 to 2010 dominated by equatorward redistribution of emissions

Since 1980, anthropogenic emissions of ozone precursors have decreased in developed regions, but increased in developing regions, particularly East and South Asia, redistributing emissions equatorwards^1-4. Modeling studies have shown that the tropospheric ozone burden (B _O3) is much more sensitive to emission changes in the tropics and Southern Hemisphere (SH) than other regions^5-9. However, the effect of the spatial redistribution of emissions has not been isolated. Here we use a global chemical transport model to consider changes in anthropogenic short-lived emissions from 1980 to 2010, and separate the influence of changes in the spatial distribution of emissions from the total emission increase, on B _O3 and surface ozone. We estimate that the spatial distribution change increased B _O3 by slightly more than the combined influences of changes in the global emission magnitude itself and in global methane. These results are explained by the strong convection, fast reaction rates, and strong NO_x sensitivity in the tropics and subtropics. Emissions increases in Southeast, East, and South Asia may be most important for the B _O3 change. The spatial distribution of emissions has a dominant effect on global tropospheric ozone, suggesting that the future ozone burden will be determined mainly by emissions from the tropics and subtropics.

Formaldehyde column density measurements as a suitable pathway to estimate near-surface ozone tendencies from space

In support of future satellite missions that aim to address the current shortcomings in measuring air quality from space, NASA's Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field campaign was designed to enable exploration of relationships between column measurements of trace species relevant to air quality at high spatial and temporal resolution. In the DISCOVER-AQ data set, a modest correlation (r 2 = 0.45) between ozone (O3) and formaldehyde (CH2O) column densities was observed. Further analysis revealed regional variability in the O3-CH2O relationship, with Maryland having a strong relationship when data were viewed temporally and Houston having a strong relationship when data were viewed spatially. These differences in regional behavior are attributed to differences in volatile organic compound (VOC) emissions. In Maryland, biogenic VOCs were responsible for ~28% of CH2O formation within the boundary layer column, causing CH2O to, in general, increase monotonically throughout the day. In Houston, persistent anthropogenic emissions dominated the local hydrocarbon environment, and no discernable diurnal trend in CH2O was observed. Box model simulations suggested that ambient CH2O mixing ratios have a weak diurnal trend (±20% throughout the day) due to photochemical effects, and that larger diurnal trends are associated with changes in hydrocarbon precursors. Finally, mathematical relationships were developed from first principles and were able to replicate the different behaviors seen in Maryland and Houston. While studies would be necessary to validate these results and determine the regional applicability of the O3-CH2O relationship, the results presented here provide compelling insight into the ability of future satellite missions to aid in monitoring near-surface air quality.

Analysis of the latitudinal variability of tropospheric ozone in the Arctic using the large number of aircraft and ozonesonde observations in early summer 2008

The goal of the paper are to: (1) present tropospheric ozone (O₃) climatologies in summer 2008 based on a large amount of measurements, during the International Polar Year when the Polar Study using Aircraft, Remote Sensing, Surface Measurements, and Models of Climate Chemistry, Aerosols, and Transport (POLARCAT) campaigns were conducted (2) investigate the processes that determine O₃ concentrations in two different regions (Canada and Greenland) that were thoroughly studied using measurements from 3 aircraft and 7 ozonesonde stations. This paper provides an integrated analysis of these observations and the discussion of the latitudinal and vertical variability of tropospheric ozone north of 55°N during this period is performed using a regional model (WFR-Chem). Ozone, CO and potential vorticity (PV) distributions are extracted from the simulation at the measurement locations. The model is able to reproduce the O₃ latitudinal and vertical variability but a negative O3 bias of 6-15 ppbv is found in the free troposphere over 4 km, especially over Canada. Ozone average concentrations are of the order of 65 ppbv at altitudes above 4 km both over Canada and Greenland, while they are less than 50 ppbv in the lower troposphere. The relative influence of stratosphere-troposphere exchange (STE) and of ozone production related to the local biomass burning (BB) emissions is discussed using differences between average values of O₃, CO and PV for Southern and Northern Canada or Greenland and two vertical ranges in the troposphere: 0-4 km and 4-8 km. For Canada, the model CO distribution and the weak correlation (< 30%) of O₃ and PV suggests that stratosphere-troposphere exchange (STE) is not the major contribution to average tropospheric ozone at latitudes less than 70°N, due to the fact that local biomass burning (BB) emissions were significant during the 2008 summer period. Conversely over Greenland, significant STE is found according to the better O₃ versus PV correlation (> 40%) and the higher 75th PV percentile. A weak negative latitudinal summer ozone gradient -6 to -8 ppbv is found over Canada in the mid troposphere between 4 and 8 km. This is attributed to an efficient O₃ photochemical production due to the BB emissions at latitudes less than 65°N, while STE contribution is more homogeneous in the latitude range 55°N to 70°N. A positive ozone latitudinal gradient of 12 ppbv is observed in the same altitude range over Greenland not because of an increasing latitudinal influence of STE, but because of different long range transport from multiple mid-latitude sources (North America, Europe and even Asia for latitudes higher than 77°N).

Ground-based assessment of the bias and long-term stability of fourteen limb and occultation ozone profile data records

The ozone profile records of a large number of limb and occultation satellite instruments are widely used to address several key questions in ozone research. Further progress in some domains depends on a more detailed understanding of these data sets, especially of their long-term stability and their mutual consistency. To this end, we made a systematic assessment of fourteen limb and occultation sounders that, together, provide more than three decades of global ozone profile measurements. In particular, we considered the latest operational Level-2 records by SAGE II, SAGE III, HALOE, UARS MLS, Aura MLS, POAM II, POAM III, OSIRIS, SMR, GOMOS, MIPAS, SCIAMACHY, ACE-FTS and MAESTRO. Central to our work is a consistent and robust analysis of the comparisons against the ground-based ozonesonde and stratospheric ozone lidar networks. It allowed us to investigate, from the troposphere up to the stratopause, the following main aspects of satellite data quality: long-term stability, overall bias, and short-term variability, together with their dependence on geophysical parameters and profile representation. In addition, it permitted us to quantify the overall consistency between the ozone profilers. Generally, we found that between 20-40 km the satellite ozone measurement biases are smaller than ±5 %, the short-term variabilities are less than 5-12% and the drifts are at most ±5% decade^-1 (or even ±3 % decade^-1 for a few records). The agreement with ground-based data degrades somewhat towards the stratopause and especially towards the tropopause where natural variability and low ozone abundances impede a more precise analysis. In part of the stratosphere a few records deviate from the preceding general conclusions; we identified biases of 10% and more (POAM II and SCIAMACHY), markedly higher single-profile variability (SMR and SCIAMACHY), and significant long-term drifts (SCIAMACHY, OSIRIS, HALOE, and possibly GOMOS and SMR as well). Furthermore, we reflected on the repercussions of our findings for the construction, analysis and interpretation of merged data records. Most notably, the discrepancies between several recent ozone profile trend assessments can be mostly explained by instrumental drift. This clearly demonstrates the need for systematic comprehensive multi-instrument comparison analyses.

Frequency and Impact of Summertime Stratospheric Intrusions over Maryland during DISCOVER-AQ (2011): New Evidence from NASA's GEOS-5 Simulations

Aircraft observations and ozonesonde profiles collected on July 14 and 27, 2011, during the Maryland month-long DISCOVER-AQ campaign, indicate the presence of stratospheric air just above the planetary boundary layer (PBL). This raises the question of whether summer stratospheric intrusions (SIs) elevate surface ozone levels and to what degree they influence background ozone levels and contribute to ozone production. We used idealized stratospheric air tracers, along with observations, to determine the frequency and extent of SIs in Maryland during July 2011. On 4 of 14 flight days, SIs were detected in layers that the aircraft encountered above the PBL from the coincidence of enhanced ozone, moderate CO, and low moisture. Satellite observations of lower tropospheric humidity confirmed the occurrence of synoptic scale influence of SIs as do simulations with the GEOS-5 Atmospheric General Circulation Model. The evolution of GEOS-5 stratospheric air tracers agree with the timing and location of observed stratospheric influence and indicate that more than 50% of air in SI layers above the PBL had resided in the stratosphere within the previous 14 days. Despite having a strong influence in the lower free troposphere, these events did not significantly affect surface ozone, which remained low on intrusion days. The model indicates similar frequencies of stratospheric influence during all summers from 2009-2013. GEOS-5 results suggest that, over Maryland, the strong inversion capping the summer PBL limits downward mixing of stratospheric air during much of the day, helping to preserve low surface ozone associated with frontal passages that precede SIs.

CAMx Ozone Source Attribution in the Eastern United States using Guidance from Observations during DISCOVER-AQ Maryland

A Comprehensive Air-Quality Model with Extensions (CAMx) version 6.10 simulation was assessed through comparison with data acquired during NASA's 2011 DISCOVER-AQ Maryland field campaign. Comparisons for the baseline simulation (CB05 chemistry, EPA 2011 National Emissions Inventory) show a model overestimate of NO_y by +86.2% and an underestimate of HCHO by -28.3%. We present a new model framework (CB6r2 chemistry, MEGAN v2.1 biogenic emissions, 50% reduction in mobile NO_x, enhanced representation of isoprene nitrates) that better matches observations. The new model framework attributes 31.4% more surface ozone in Maryland to electric generating units (EGUs) and 34.6% less ozone to on-road mobile sources. Surface ozone becomes more NO_x-limited throughout the eastern United States compared to the baseline simulation. The baseline model therefore likely underestimates the effectiveness of anthropogenic NO_x reductions as well as the current contribution of EGUs to surface ozone.

Tropospheric ozonesonde profiles at long-term U.S. monitoring sites: 1. A climatology based on self-organizing maps

Sonde-based climatologies of tropospheric ozone (O₃) are vital for developing satellite retrieval algorithms and evaluating chemical transport model output. Typical O₃ climatologies average measurements by latitude or region, and season. Recent analysis using self-organizing maps (SOM) to cluster ozonesondes from two tropical sites found clusters of O₃ mixing ratio profiles are an excellent way to capture O₃ variability and link meteorological influences to O₃ profiles. Clusters correspond to distinct meteorological conditions, e.g. convection, subsidence, cloud cover, and transported pollution. Here, the SOM technique is extended to four long-term U.S. sites (Boulder, CO; Huntsville, AL; Trinidad Head, CA; Wallops Island, VA) with 4530 total profiles. Sensitivity tests on k-means algorithm and SOM justify use of 3×3 SOM (nine clusters). At each site, SOM clusters together O₃ profiles with similar tropopause height, 500 hPa height/temperature, and amount of tropospheric and total column O₃. Cluster means are compared to monthly O₃ climatologies. For all four sites, near-tropopause O₃ is double (over +100 parts per billion by volume; ppbv) the monthly climatological O₃ mixing ratio in three clusters that contain 13 - 16% of profiles, mostly in winter and spring. Large mid-tropospheric deviations from monthly means (-6 ppbv, +7 - 10 ppbv O₃ at 6 km) are found in two of the most populated clusters (combined 36 - 39% of profiles). These two clusters contain distinctly polluted (summer) and clean O₃ (fall-winter, high tropopause) profiles, respectively. As for tropical profiles previously analyzed with SOM, O₃ averages are often poor representations of U.S. O₃ profile statistics.

Abstract P3-07-23: CYP2D6 genotype and breast cancer recurrence in tamoxifen treated patients: An evaluation of the importance of loss-of-heterozygosity

Background: Tamoxifen therapy for estrogen receptor positive (ER+) breast cancer reduces recurrence risk by about half. Steady-state concentrations of endoxifen, a potent anti-estrogenic tamoxifen metabolite, are reduced in women whose CYP2D6 genotypes confer poor enzyme function. Many studies have measured associations between genetically impaired CYP2D6 function and tamoxifen resistance. It has been suggested that the subset of studies using DNA extracted from tumor-infiltrated tissue may have been susceptible to genotyping error induced by loss of heterozygosity (LOH); the putative non-differential genotype misclassification may have biased these studies' estimates toward the null. We reviewed the clinical epidemiology studies conducted to date to assess the importance of loss-of-heterozygosity (LOH) at the CYP2D6 locus and its implications for assessing tamoxifen effectiveness.

Methods: We searched for the terms "tamoxifen" and "CYP2D6" in PubMed, including all papers and abstracts through 31 May 2015 on the association of CYP2D6 gene variants and the risk of breast cancer recurrence or mortality. We used a quantitative bias analysis (QBA) to evaluate the importance of genotype misclassification in studies that extracted DNA from tumor-infiltrated tissue. We conducted a random effects meta-analysis to evaluate all studies simultaneously, and within groups according to whether DNA was derived from tumor-infiltrated tissue or non-neoplastic tissue.

Results: Thirty-one studies investigated CYP2D6 genotype and breast cancer recurrence, yielding relative effect estimates ranging from 0.08 to 14. DNA was extracted from blood or non-neoplastic tissue in 21 of these 31 studies (68%), and from tumor-infiltrated tissue in the remaining 10 (32%). Our analysis of the association between variant/variant genotype compared with wildtype/wildtype genotype included 21 of the 31 studies. Sixteen (76%) of these 21 studies extracted DNA from blood or non-neoplastic tissue and five (24%) extracted DNA from tumor-infiltrated tissue. Genotype misclassification parameters for the QBA were estimated from six concordance studies. There was little difference between the effect estimates (EE) and 95% confidence/simulation intervals (95% CI/SI) before and after QBA (EE=1.71, 95%CI=1.24, 2.36, and 1.80 95%SI=1.28, 2.54, respectively). Studies using non-neoplastic DNA had higher variance than those based on tumor-infiltrated tissue DNA, half reported implausibly high EE, and many were susceptible to design and analysis errors that would bias estimates of association away from the null.

Conclusions: We found little relative bias in the summary estimates of association, either overall or when limited to the tumor-infiltrated tissue DNA studies. Three guideline panels, based on robust evidence, recommend against CYP2D6 genotype-guided tamoxifen therapy. Alternatives for optimizing the effectiveness of tamoxifen therapy, such as assuring adherence and persistence, are more likely to achieve clinically important benefits.

Citation Format: Ahern TP, Hertz DL, Damkier P, Ejlertsen B, Hamilton-Dutoit SJ, Rae JM, Regan MM, Thompson AM, Lash TL, Cronin-Fenton DP. CYP2D6 genotype and breast cancer recurrence in tamoxifen treated patients: An evaluation of the importance of loss-of-heterozygosity. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-23.

Abstract P5-07-15: Breast cancer estrogen receptor scoring in tissue microarrays: Specialist breast pathologist versus automation

Rationale: Tissue microarrays (TMAs) have become a valuable resource for biomarker expression in translational research. Immunohistochemical (IHC) assessment of TMAs is the principal method for analyzing protein expression in large numbers of patient samples efficient with conservation of tissue. However, manual IHC assessment of TMAs remains a challenging and laborious task. With advances in image analysis, computer generated analyses of TMAs have the potential to lessen the burden of expert pathologist review. Computerized ER scoring relies on tumor localization.

Aim: The objective of this study was to compare the effectiveness of a locally developed automated invasive tumor location system with the skills of specialist breast pathologists.

Methods: In this study, tumor localization for estrogen receptor (ER) scoring was evaluated comparing computer- generated segmentation masks with those of two specialist breast pathologists. Automated tumor localization was achieved using a novel image analysis algorithm, which labeled compact groups of pixels called superpixels. Machine learning techniques were adopted to model color, shape and textural properties of superpixels in a rotation invariant manner, suitable for histopathology images. The resulting automatically and manually-obtained segmentation masks were used to obtain IHC scores for thirty-two ER stained invasive breast cancer TMA samples using FDA-approved IHC scoring software.

Results: Pixel-level comparisons showed lower agreement between automated and manual segmentation masks (κ = 0.84) than between pathologists' masks (κ = 0.91). However, this had little impact on computed IHC scores (Allred method; κ = 0.91, Quickscore method; κ = 0.92).

Conclusion: The automated system provides sufficiently consistent measurements for standardized IHC analysis of nuclear staining in TMAs from large clinical trials.

Citation Format: Jordan LB, Akbar S, Purdie CA, Thompson AM, McKenna SJ. Breast cancer estrogen receptor scoring in tissue microarrays: Specialist breast pathologist versus automation. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-07-15.

Origins of tropospheric ozone interannual variation (IAV) over Réunion: A model investigation

Observations from long-term ozonesonde measurements show robust variations and trends in the evolution of ozone in the middle and upper troposphere over Réunion Island (21.1°S, 55.5°E) in June-August. Here we examine possible causes of the observed ozone variation at Réunion Island using hindcast simulations by the stratosphere-troposphere Global Modeling Initiative chemical transport model (GMI-CTM) for 1992-2014, driven by assimilated Modern-Era Retrospective Analysis for Research and Applications (MERRA) meteorological fields. Réunion Island is at the edge of the subtropical jet, a region of strong stratospheric-tropospheric exchange (STE). Our analysis implies that the large interannual variation (IAV) of upper tropospheric ozone over Réunion is driven by the large IAV of the stratospheric influence. The IAV of the large-scale, quasi-horizontal wind patterns also contributes to the IAV of ozone in the upper troposphere. Comparison to a simulation with constant emissions indicates that increasing emissions do not lead to the maximum trend in the middle and upper troposphere over Réunion during austral winter implied by the sonde data. The effects of increasing emission over southern Africa are limited to the lower troposphere near the surface in August - September.

A pervasive role for biomass burning in tropical high ozone/low water structures

Air parcels with mixing ratios of high O3 and low H2O (HOLW) are common features in the tropical western Pacific (TWP) mid-troposphere (300-700 hPa). Here, using data collected during aircraft sampling of the TWP in winter 2014, we find strong, positive correlations of O3 with multiple biomass burning tracers in these HOLW structures. Ozone levels in these structures are about a factor of three larger than background. Models, satellite data and aircraft observations are used to show fires in tropical Africa and Southeast Asia are the dominant source of high O3 and that low H2O results from large-scale descent within the tropical troposphere. Previous explanations that attribute HOLW structures to transport from the stratosphere or mid-latitude troposphere are inconsistent with our observations. This study suggest a larger role for biomass burning in the radiative forcing of climate in the remote TWP than is commonly appreciated.

Why do Models Overestimate Surface Ozone in the Southeastern United States?

Ozone pollution in the Southeast US involves complex chemistry driven by emissions of anthropogenic nitrogen oxide radicals (NO_x ≡ NO + NO₂) and biogenic isoprene. Model estimates of surface ozone concentrations tend to be biased high in the region and this is of concern for designing effective emission control strategies to meet air quality standards. We use detailed chemical observations from the SEAC⁴RS aircraft campaign in August and September 2013, interpreted with the GEOS-Chem chemical transport model at 0.25°×0.3125° horizontal resolution, to better understand the factors controlling surface ozone in the Southeast US. We find that the National Emission Inventory (NEI) for NO_x from the US Environmental Protection Agency (EPA) is too high. This finding is based on SEAC⁴RS observations of NO_x and its oxidation products, surface network observations of nitrate wet deposition fluxes, and OMI satellite observations of tropospheric NO₂ columns. Our results indicate that NEI NO_x emissions from mobile and industrial sources must be reduced by 30-60%, dependent on the assumption of the contribution by soil NO_x emissions. Upper tropospheric NO₂ from lightning makes a large contribution to satellite observations of tropospheric NO₂ that must be accounted for when using these data to estimate surface NO_x emissions. We find that only half of isoprene oxidation proceeds by the high-NO_x pathway to produce ozone; this fraction is only moderately sensitive to changes in NO_x emissions because isoprene and NO_x emissions are spatially segregated. GEOS-Chem with reduced NO_x emissions provides an unbiased simulation of ozone observations from the aircraft, and reproduces the observed ozone production efficiency in the boundary layer as derived from a regression of ozone and NO_x oxidation products. However, the model is still biased high by 8±13 ppb relative to observed surface ozone in the Southeast US. Ozonesondes launched during midday hours show a 7 ppb ozone decrease from 1.5 km to the surface that GEOS-Chem does not capture. This bias may reflect a combination of excessive vertical mixing and net ozone production in the model boundary layer.

Magnetic resonance imaging texture analysis classification of primary breast cancer

OBJECTIVES

Patient-tailored treatments for breast cancer are based on histological and immunohistochemical (IHC) subtypes. Magnetic Resonance Imaging (MRI) texture analysis (TA) may be useful in non-invasive lesion subtype classification.

METHODS

Women with newly diagnosed primary breast cancer underwent pre-treatment dynamic contrast-enhanced breast MRI. TA was performed using co-occurrence matrix (COM) features, by creating a model on retrospective training data, then prospectively applying to a test set. Analyses were blinded to breast pathology. Subtype classifications were performed using a cross-validated k-nearest-neighbour (k = 3) technique, with accuracy relative to pathology assessed and receiver operator curve (AUROC) calculated. Mann-Whitney U and Kruskal-Wallis tests were used to assess raw entropy feature values.

RESULTS

Histological subtype classifications were similar across training (n = 148 cancers) and test sets (n = 73 lesions) using all COM features (training: 75%, AUROC = 0.816; test: 72.5%, AUROC = 0.823). Entropy features were significantly different between lobular and ductal cancers (p < 0.001; Mann-Whitney U). IHC classifications using COM features were also similar for training and test data (training: 57.2%, AUROC = 0.754; test: 57.0%, AUROC = 0.750). Hormone receptor positive and negative cancers demonstrated significantly different entropy features. Entropy features alone were unable to create a robust classification model.

CONCLUSION

Textural differences on contrast-enhanced MR images may reflect underlying lesion subtypes, which merits testing against treatment response.

KEY POINTS

• MR-derived entropy features, representing heterogeneity, provide important information on tissue composition. • Entropy features can differentiate between histological and immunohistochemical subtypes of breast cancer. • Differing entropy features between breast cancer subtypes implies differences in lesion heterogeneity. • Texture analysis of breast cancer potentially provides added information for decision making.

Effects of local meteorology and aerosols on ozone and nitrogen dioxide retrievals from OMI and pandora spectrometers in Maryland, USA during DISCOVER-AQ 2011

An analysis is presented for both ground- and satellite-based retrievals of total column ozone and nitrogen dioxide levels from the Washington, D.C., and Baltimore, Maryland, metropolitan area during the NASA-sponsored July 2011 campaign of Deriving Information on Surface COnditions from Column and VERtically Resolved Observations Relevant to Air Quality (DISCOVER-AQ). Satellite retrievals of total column ozone and nitrogen dioxide from the Ozone Monitoring Instrument (OMI) on the Aura satellite are used, while Pandora spectrometers provide total column ozone and nitrogen dioxide amounts from the ground. We found that OMI and Pandora agree well (residuals within ±25 % for nitrogen dioxide, and ±4.5 % for ozone) for a majority of coincident observations during July 2011. Comparisons with surface nitrogen dioxide from a Teledyne API 200 EU NO_x Analyzer showed nitrogen dioxide diurnal variability that was consistent with measurements by Pandora. However, the wide OMI field of view, clouds, and aerosols affected retrievals on certain days, resulting in differences between Pandora and OMI of up to ±65 % for total column nitrogen dioxide, and ±23 % for total column ozone. As expected, significant cloud cover (cloud fraction >0.2) was the most important parameter affecting comparisons of ozone retrievals; however, small, passing cumulus clouds that do not coincide with a high (>0.2) cloud fraction, or low aerosol layers which cause significant backscatter near the ground affected the comparisons of total column nitrogen dioxide retrievals. Our results will impact post-processing satellite retrieval algorithms and quality control procedures.

Bay breeze influence on surface ozone at Edgewood, MD during July 2011

Surface ozone (O₃) was analyzed to investigate the role of the bay breeze on air quality at two locations in Edgewood, Maryland (lat: 39.4°, lon: -76.3°) for the month of July 2011. Measurements were taken as part of the first year of NASA's "Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality" (DISCOVER-AQ) Earth Venture campaign and as part of NASA's Geostationary for Coastal and Air Pollution Events Chesapeake Bay Oceanographic campaign with DISCOVER-AQ (Geo-CAPE CBODAQ). Geo-CAPE CBODAQ complements DISCOVER-AQ by providing ship-based observations over the Chesapeake Bay. A major goal of DISCOVER-AQ is determining the relative roles of sources, photochemistry and local meteorology during air quality events in the Mid-Atlantic region of the U.S. Surface characteristics, transport and vertical structures of O₃ during bay breezes were identified using in-situ surface, balloon and aircraft data, along with remote sensing equipment. Localized late day peaks in O₃ were observed during bay breeze days, maximizing an average of 3 h later compared to days without bay breezes. Of the 10 days of July 2011 that violated the U.S. Environmental Protection Agency (EPA) 8 h O₃ standard of 75 parts per billion by volume (ppbv) at Edgewood, eight exhibited evidence of a bay breeze circulation. The results indicate that while bay breezes and the processes associated with them are not necessary to cause exceedances in this area, bay breezes exacerbate poor air quality that sustains into the late evening hours at Edgewood. The vertical and horizontal distributions of O₃ from the coastal Edgewood area to the bay also show large gradients that are often determined by boundary layer stability. Thus, developing air quality models that can sufficiently resolve these dynamics and associated chemistry, along with more consistent monitoring of O₃ and meteorology on and along the complex coastline of Chesapeake Bay must be a high priority.

Ozone correlations between mid-tropospheric partial columns and the near-surface at two mid-atlantic sites during the DISCOVER-AQ campaign in July 2011

The current network of ground-based monitors for ozone (O₃) is limited due to the spatial heterogeneity of O₃ at the surface. Satellite measurements can provide a solution to this limitation, but the lack of sensitivity of satellites to O₃ within the boundary layer causes large uncertainties in satellite retrievals at the near-surface. The vertical variability of O₃ was investigated using ozonesondes collected as part of NASA's Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) campaign during July 2011 in the Baltimore, MD/Washington D.C. metropolitan area. A subset of the ozonesonde measurements was corrected for a known bias from the electrochemical solution strength using new procedures based on laboratory and field tests. A significant correlation of O₃ over the two sites with ozonesonde measurements (Edgewood and Beltsville, MD) was observed between the mid-troposphere (7-10 km) and the near-surface (1-3 km). A linear regression model based on the partial column amounts of O₃ within these subregions was developed to calculate the near-surface O₃ using mid-tropospheric satellite measurements from the Tropospheric Emission Spectrometer (TES) onboard the Aura spacecraft. The uncertainties of the calculated near-surface O₃ using TES mid-tropospheric satellite retrievals and a linear regression model were less than 20 %, which is less than that of the observed variability of O₃ at the surface in this region. These results utilize a region of the troposphere to which existing satellites are more sensitive compared to the boundary layer and can provide information of O₃ at the near-surface using existing satellite infrastructure and algorithms.

Bay breeze climatology at two sites along the Chesapeake bay from 1986-2010: Implications for surface ozone

Hourly surface meteorological measurements were coupled with surface ozone (O₃) mixing ratio measurements at Hampton, Virginia and Baltimore, Maryland, two sites along the Chesapeake Bay in the Mid-Atlantic United States, to examine the behavior of surface O₃ during bay breeze events and quantify the impact of the bay breeze on local O₃ pollution. Analyses were performed for the months of May through September for the years 1986 to 2010. The years were split into three groups to account for increasingly stringent environmental regulations that reduced regional emissions of nitrogen oxides (NO_x): 1986-1994, 1995-2002, and 2003-2010. Each day in the 25-year record was marked either as a bay breeze day, a non-bay breeze day, or a rainy/cloudy day based on the meteorological data. Mean eight hour (8-h) averaged surface O₃ values during bay breeze events were 3 to 5 parts per billion by volume (ppbv) higher at Hampton and Baltimore than on non-bay breeze days in all year periods. Anomalies from mean surface O₃ were highest in the afternoon at both sites during bay breeze days in the 2003-2010 study period. In conjunction with an overall lowering of baseline O₃ after the 1995-2002 period, the percentage of total exceedances of the Environmental Protection Agency (EPA) 75 ppbv 8-h O₃ standard that occurred on bay breeze days increased at Hampton for 2003-2010, while remaining steady at Baltimore. These results suggest that bay breeze circulations are becoming more important to causing exceedance events at particular sites in the region, and support the hypothesis of Martins et al. (2012) that highly localized meteorology increasingly drives air quality events at Hampton.

Evaluation of NAQFC model performance in forecasting surface ozone during the 2011 DISCOVER-AQ campaign

The National Air Quality Forecast Capability (NAQFC) and an experimental version of the NAQFC (NAQFC-β) provided flight decision support during the July 2011 NASA DISCOVER-AQ field campaign around Baltimore, Maryland. Ozone forecasts from the NAQFC and NAQFC-β were compared to surface observations at six air quality monitoring stations in the DISCOVER-AQ domain. A bootstrap algorithm was used to test for significant bias and error in the forecasts from each model. Both models produce significant positively biased forecasts in the morning while generally becoming insignificantly biased in the afternoon during peak ozone hours. The NAQFC-β produces higher forecast bias, higher forecast error, and lower correlations than the NAQFC. Forecasts from the two models were also compared to each other to determine the spatial and temporal extent of significant differences in forecasted ozone using a bootstrap algorithm. The NAQFC-β tends to produce an average background ozone mixing ratio of at least 3.51 ppbv greater than the NAQFC throughout the domain at 95 % significance. The difference between the two models is significant during the overnight and early morning hours likely due to the way the Carbon Bond 5 mechanism in the NAQFC-β handles reactive nitrogen recycling and organic peroxide species. The value of information each model provides was tested using a static cost-loss ratio model. By standard measures of forecast skill, the NAQFC generally outperforms the NAQFC-β; however, the NAQFC-β provides greater value of information. This is because standard measures of forecast skill often hide the sensitivity of end users' needs to forecast error.

NEOCENT: a randomised feasibility and translational study comparing neoadjuvant endocrine therapy with chemotherapy in ER-rich postmenopausal primary breast cancer

Neoadjuvant endocrine therapy is an alternative to chemotherapy for women with oestrogen receptor (ER)-positive early breast cancer (BC). We aimed to assess feasibility of recruiting patients to a study comparing chemotherapy versus endocrine therapy in postmenopausal women with ER-rich primary BC, and response as well as translational endpoints were assessed. Patients requiring neoadjuvant therapy were randomised to chemotherapy: 6 × 3-weekly cycles FE₁₀₀C or endocrine therapy: letrozole 2.5 mg, daily for 18-23 weeks. Primary endpoints were recruitment feasibility and tissue collection. Secondary endpoints included clinical, radiological and pathological response rates, quality of life and translational endpoints. 63/80 patients approached were eligible, of those 44 (70, 95% CI 57-81) were randomised. 12 (54.5, 95% CI 32.2-75.6) chemotherapy patients showed radiological objective response compared with 13 (59.1, 95% CI 36.4-79.3) letrozole patients. Compared with baseline, mean Ki-67 levels fell in both groups at days 2-4 and at surgery [fold change: 0.24 (95% CI 0.12-0.51) and 0.24; (95% CI 0.15-0.37), respectively]. Plasma total cfDNA levels rose from baseline to week 8 [fold change: chemotherapy 2.10 (95% CI 1.47-3.00), letrozole 1.47(95% CI 0.98-2.20)], and were maintained at surgery in the chemotherapy group [chemotherapy 2.63; 95% CI 1.56-4.41), letrozole 0.95 (95% CI 0.71-1.26)]. An increase in plasma let-7a miRNA was seen at surgery for patients with objective radiological response to chemotherapy. Recruitment and tissue collection endpoints were met; however, a larger trial was deemed unfeasible due to slow accrual. Both regimens were equally efficacious. Dynamic changes were seen in Ki-67 and circulating biomarkers in both groups with increases in cfDNA and let-7a miRNA persisting until surgery for chemotherapy patients.

Microfluidics for single-cell genetic analysis

The ability to correlate single-cell genetic information to cellular phenotypes will provide the kind of detailed insight into human physiology and disease pathways that is not possible to infer from bulk cell analysis. Microfluidic technologies are attractive for single-cell manipulation due to precise handling and low risk of contamination. Additionally, microfluidic single-cell techniques can allow for high-throughput and detailed genetic analyses that increase accuracy and decrease reagent cost compared to bulk techniques. Incorporating these microfluidic platforms into research and clinical laboratory workflows can fill an unmet need in biology, delivering the highly accurate, highly informative data necessary to develop new therapies and monitor patient outcomes. In this perspective, we describe the current and potential future uses of microfluidics at all stages of single-cell genetic analysis, including cell enrichment and capture, single-cell compartmentalization and manipulation, and detection and analyses.