Non-centrosymmetric topological phase probed by non-linear Hall effect

Non-centrosymmetric topological material has attracted intense attention due to its superior characteristics as compared with the centrosymmetric one, although probing the local quantum geometry in non-centrosymmetric topological material remains challenging. The non-linear Hall (NLH) effect provides an ideal tool to investigate the local quantum geometry. Here, we report a non-centrosymmetric topological phase in ZrTe5, probed by using the NLH effect. The angle-resolved and temperature-dependent NLH measurement reveals the inversion and ab-plane mirror symmetries breaking at <30 K, consistently with our theoretical calculation. Our findings identify a new non-centrosymmetric phase of ZrTe5 and provide a platform to probe and control local quantum geometry via crystal symmetries.

A versatile model with three-dimensional triangular lattice for unconventional transport and various topological effects

The finite Berry curvature in topological materials can induce many subtle phenomena, such as the anomalous Hall effect (AHE), spin Hall effect (SHE), anomalous Nernst effect (ANE), non-linear Hall effect (NLHE) and bulk photovoltaic effects. To explore these novel physics as well as their connection and coupling, a precise and effective model should be developed. Here, we propose such a versatile model-a 3D triangular lattice with alternating hopping parameters, which can yield various topological phases, including kagome bands, triply degenerate fermions, double Weyl semimetals and so on. We reveal that this special lattice can present unconventional transport due to its unique topological surface states and the aforementioned topological phenomena, such as AHE, ANE, NLHE and the topological photocurrent effect. In addition, we also provide a number of material candidates that have been synthesized experimentally with this lattice, and discuss two materials, including a non-magnetic triangular system for SHE, NLHE and the shift current, and a ferromagnetic triangular lattice for AHE and ANE. Our work provides an excellent platform, including both the model and materials, for the study of Berry-curvature-related physics.

Superconducting, Topological, and Transport Properties of Kagome Metals CsTi3Bi5 and RbTi3Bi5

The recently discovered ATi3Bi5 (A=Cs, Rb) exhibit intriguing quantum phenomena including superconductivity, electronic nematicity, and abundant topological states. ATi3Bi5 present promising platforms for studying kagome superconductivity, band topology, and charge orders in parallel with AV3Sb5. In this work, we comprehensively analyze various properties of ATi3Bi5 covering superconductivity under pressure and doping, band topology under pressure, thermal conductivity, heat capacity, electrical resistance, and spin Hall conductivity (SHC) using first-principles calculations. Calculated superconducting transition temperature (Tc) of CsTi3Bi5 and RbTi3Bi5 at ambient pressure are about 1.85 and 1.92 K. When subject to pressure, Tc of CsTi3Bi5 exhibits a special valley and dome shape, which arises from quasi-two-dimensional compression to three-dimensional isotropic compression within the context of an overall decreasing trend. Furthermore, Tc of RbTi3Bi5 can be effectively enhanced up to 3.09 K by tuning the kagome van Hove singularities (VHSs) and flat band through doping. Pressures can also induce abundant topological surface states at the Fermi energy (EF) and tune VHSs across EF. Additionally, our transport calculations are in excellent agreement with recent experiments, confirming the absence of charge density wave. Notably, SHC of CsTi3Bi5 can reach up to 226ℏ ·(e· Ω ·cm)-1 at EF. Our work provides a timely and detailed analysis of the rich physical properties for ATi3Bi5, offering valuable insights for further experimental verifications and investigations in this field.

Interplay of the charge density wave transition with topological and superconducting properties

Exotic phenomena due to the interplay of different quantum orders have been observed and the study of these phenomena has emerged as a new frontier in condensed matter research, especially in the two-dimensional limit. Here, we report the coexistence of charge density waves (CDWs), superconductivity, and nontrivial topology in monolayer 1H-MSe2 (M = Nb, Ta) triggered by momentum-dependent electron-phonon coupling through electron doping. At a critical electron doping concentration, new 2 × 2 CDW phases emerge with nontrivial topology, Dirac cones, and van Hove singularities. Interestingly, these 2 × 2 CDW phases are also superconducting. Our findings not only reveal a route towards realizing nontrivial electronic characters by CDW engineering, but also provide an exciting platform to modulate different quantum states at the confluence of CDWs, superconductivity, nontrivial topology, and electron-phonon coupling.

Observation of flat band, Dirac nodal lines and topological surface states in Kagome superconductor CsTi3Bi5

Kagome lattices of various transition metals are versatile platforms for achieving anomalous Hall effects, unconventional charge-density wave orders and quantum spin liquid phenomena due to the strong correlations, spin-orbit coupling and/or magnetic interactions involved in such a lattice. Here, we use laser-based angle-resolved photoemission spectroscopy in combination with density functional theory calculations to investigate the electronic structure of the newly discovered kagome superconductor CsTi₃Bi₅, which is isostructural to the AV₃Sb₅ (A = K, Rb or Cs) kagome superconductor family and possesses a two-dimensional kagome network of titanium. We directly observe a striking flat band derived from the local destructive interference of Bloch wave functions within the kagome lattice. In agreement with calculations, we identify type-II and type-III Dirac nodal lines and their momentum distribution in CsTi₃Bi₅ from the measured electronic structures. In addition, around the Brillouin zone centre, [Formula: see text] nontrivial topological surface states are also observed due to band inversion mediated by strong spin-orbit coupling.

Intertwining of Magnetism and Charge Ordering in Kagome FeGe

Recent experiments report a charge density wave (CDW) in the antiferromagnet FeGe, but the nature of the charge ordering and the associated structural distortion remains elusive. We discuss the structural and electronic properties of FeGe. Our proposed ground state phase accurately captures atomic topographies acquired by scanning tunneling microscopy. We show that the 2 × 2 × 1 CDW likely results from the Fermi surface nesting of hexagonal-prism-shaped kagome states. FeGe is found to exhibit distortions in the positions of the Ge atoms instead of the Fe atoms in the kagome layers. Using in-depth first-principles calculations and analytical modeling, we demonstrate that this unconventional distortion is driven by the intertwining of magnetic exchange coupling and CDW interactions in this kagome material. The movement of Ge atoms from their pristine positions also enhances the magnetic moment of the Fe kagome layers. Our study indicates that magnetic kagome lattices provide a material candidate for exploring the effects of strong electronic correlations on the ground state and their implications for transport, magnetic, and optical responses in materials.

Strain induced metal-semiconductor transition in two-dimensional topological half metals

Spintronic applications of two-dimensional (2D) magnetic half metals and semiconductors are thought to be very promising. Here, we suggest a family of stable 2D materials M n 2 X 7 (X = Cl, Br, and I). The monolayer M n 2 C l 7 exhibits an in-plane ferromagnetic (FM) ground state with a Curie temperature of 118 K, which is unveiled to be a 2D Weyl half semimetal with two Weyl points of opposite chirality connected by a remarkable Fermi arc. In addition, it appears that a biaxial tensile strain can lead to a metal-semiconductor phase transition as a result of the increased anomalous Jahn-Teller distortions, which raise the degeneracy of the e g energy level and cause a significant energy splitting. A 10% biaxial tensile strain also increases the Curie temperature to about 159 K, which originates from the enhanced Mn-Cl-Mn FM superexchange. Moreover, the metal-semiconductor transition can also be induced by a uniaxial strain. Our findings provide an idea to create 2D magnetic semiconductors through metal-semiconductor transition in half metals.

Atomically Unveiling an Atlas of Polytypes in Transition-Metal Trihalides

Transition-metal trihalides MX₃ (M = Cr, Ru; X = Cl, Br, and I) belong to a family of novel two-dimensional (2D) magnets that can exhibit topological magnons and electromagnetic properties, thus affording great promises in next-generation spintronic devices. Rich magnetic ground states observed in the MX₃ family are believed to be strongly correlated to the signature Kagome lattice and interlayer van der Waals coupling raised from distinct stacking orders. However, the intrinsic air instability of MX₃ makes their direct atomic-scale analysis challenging. Therefore, information on the stacking-registry-dependent magnetism for MX₃ remains elusive, which greatly hinders the engineering of desired phases. Here, we report a nondestructive transfer method and successfully realize an intact transfer of bilayer MX₃, as evidenced by scanning transmission electron microscopy (STEM). After surveying hundreds of MX₃ thin flakes, we provide a full spectrum of stacking orders in MX₃ with atomic precision and calculated their associated magnetic ground states, unveiled by combined STEM and density functional theory (DFT). In addition to well-documented phases, we discover a new monoclinic C2/c phase in the antiferromagnetic (AFM) structure widely existing in MX₃. Rich stacking polytypes, including C2/c, C2/m, R3̅, P3₁12, etc., provide rich and distinct magnetic ground states in MX₃. Besides, a high density of strain soliton boundaries is consistently found in all MX₃, combined with likely inverted structures, allowing AFM to ferromagnetic (FM) transitions in most MX₃. Therefore, our study sheds light on the structural basis of diverse magnetic orders in MX₃, paving the way for modulating magnetic couplings via stacking engineering.

Epitaxial Growth of Single-Layer Kagome Nanoflakes with Topological Band Inversion

The kagome lattice has attracted intense interest with the promise of realizing topological phases built from strongly interacting electrons. However, fabricating two-dimensional (2D) kagome materials with nontrivial topology is still a key challenge. Here, we report the growth of single-layer iron germanide kagome nanoflakes by molecular beam epitaxy. Using scanning tunneling microscopy/spectroscopy, we unravel the real-space electronic localization of the kagome flat bands. First-principles calculations demonstrate the topological band inversion, suggesting the topological nature of the experimentally observed edge mode. Apart from the intrinsic topological states that potentially host chiral edge modes, the realization of kagome materials in the 2D limit also holds promise for future studies of geometric frustration.

Topological superconductivity and large spin Hall effect in the kagome family Ti6X4 (X = Bi, Sb, Pb, Tl, and In)

Topological superconductors (TSC) become a focus of research due to the accompanying Majorana fermions. However, the reported TSC are extremely rare. Recent experiments reported kagome TSC AV₃Sb₅ (A = K, Rb, and Cs) exhibit unique superconductivity, topological surface states (TSS), and Majorana bound states. More recently, the first titanium-based kagome superconductor CsTi₃Bi₅ with nontrivial topology was successfully synthesized as a perspective TSC. Given that Cs contributes little to electronic structures of CsTi₃Bi₅ and binary compounds may be easier to be synthesized, here, by first-principle calculations, we predict five stable nonmagnetic kagome compounds Ti₆X₄ (X = Bi, Sb, Pb, Tl, and In) which exhibit superconductivity with critical temperature Tc = 3.8 K - 5.1 K, nontrivial Z 2 band topology, and TSS close to the Fermi level. Additionally, large intrinsic spin Hall effect is obtained in Ti₆X₄, which is caused by gapped Dirac nodal lines due to a strong spin-orbit coupling. This work offers new platforms for TSC and spintronic devices.

Two-Dimensional Intercalating Multiferroics with Strong Magnetoelectric Coupling

Intrinsic two-dimensional (2D) multiferroics that couple ferromagnetism and ferroelectricity are rare. Here, we present an approach to achieve 2D multiferroics using powerful intercalation technology. In this approach, metal atoms such as Cu or Ag atoms are intercalated in bilayer CrI₃ to form Cu(CrI₃)₄ or Ag(CrI₃)₄. The intercalant leads to the inversion symmetry breaking and produces a large out-of-plane electric polarization with a low transition barrier and a small reversal electric field, exhibiting excellent 2D ferroelectric properties. In addition, due to charge transfer between the intercalated atoms and bilayer CrI₃, the interlayer coupling transits from antiferromagnetic to ferromagnetic, and the intralayer ferromagnetic coupling is also enhanced. Furthermore, the built-in electric polarization causes a distinct surface magnetization difference, generating a strong magnetoelectric coupling with a coefficient larger than that of Fe, Co, and Ni thin films. Our work paves a practical path for 2D multiferroics, which may have crucial applications in spintronics.

Signature of Ultrafast Formation and Annihilation of Polaronic States in a Layered Ferromagnet

The strong interaction between charge and lattice vibration gives rise to a polaron, which has a profound effect on optical and transport properties of matters. In magnetic materials, polarons are involved in spin dependent transport, which can be potentially tailored for spintronic and opto-spintronic device applications. Here, we identify the signature of ultrafast formation of polaronic states in CrBr3. The polaronic states are long-lived, having a lifetime on the time scale of nanoseconds to microseconds, which coincides with the emission lifetime of ∼4.3 μs. Transition of the polaronic states is strongly screened by the phonon, generating a redshift of the transition energy ∼0.2 eV. Moreover, energy-dependent localization of polaronic states is discovered followed by transport/annihilation properties. These results shed light on the nature of the polarons and their formation and transport dynamics in layered magnetic materials, which paves the way for the rational design of two-dimensional magnetic devices.

Emergent Kagome Electrides

In a two-dimensional (2D) Kagome lattice, the ideal Kagome bands including Dirac cones, van Hove singularities, and a flat band are highly expected, because they can provide a promising platform to investigate novel physical phenomena. However, in the reported Kagome materials, the complex 3D and multiorder electron hoppings result in the disappearance of the ideal Kagome bands in these systems. Here, we propose an alternative way to achieve the ideal Kagome bands in non-Kagome materials by confining excess electrons in the system to the crystal interstitial sites to form a 2D Kagome lattice, coined as a Kagome electride. Then, we predict two novel stable 2D Kagome electrides in hexagonal materials Li₅Si and Li₅Sn, whose band structures are similar to the ideal Kagome bands, including topological Dirac cones with beautiful Fermi arcs in their surface states, van Hove singularities, and a flat band. In addition, Li₅Si is revealed to be a low-temperature superconductor at ambient pressure, and its superconducting transition temperature T_c can be increased from 1.1 K at 0 GPa to 7.2 K at 100 GPa. The high T_c is unveiled to be the consequence of strong electron-phonon coupling originated from the sp-hybridized phonon-coupled bands and phonon softening caused by strong Fermi nesting. Due to the strong Fermi nesting, the charge density wave phase transition occurs at 110 GPa with the lattice reconstructed from hexagonal to orthorhombic, accompanied with the increase of T_c to 10.5 K. Our findings pave an alternative way to fabricate more real materials with Kagome bands in electrides.

Epitaxial Growth of Ultraflat Bismuthene with Large Topological Band Inversion Enabled by Substrate-Orbital-Filtering Effect

Quantum spin Hall (QSH) systems hold promises of low-power-consuming spintronic devices, yet their practical applications are extremely impeded by the small energy gaps. Fabricating QSH materials with large gaps, especially under the guidance of design principles, is essential for both scientific research and practical applications. Here, we demonstrate that large on-site atomic spin-orbit coupling can be directly exploited via the intriguing substrate-orbital-filtering effect to generate large-gap QSH systems and experimentally realized on the epitaxially synthesized ultraflat bismuthene on Ag(111). Theoretical calculations reveal that the underlying substrate selectively filters Bi p_z orbitals away from the Fermi level, leading p_xy orbitals with nonzero magnetic quantum numbers, resulting in large topological gap of ∼1 eV at the K point. The corresponding topological edge states are identified through scanning tunneling spectroscopy combined with density functional theory calculations. Our findings provide general strategies to design large-gap QSH systems and further explore their topology-related physics.

P-orbital magnetic topological states on square lattice

Honeycomb or triangular lattices were extensively studied and thought to be proper platforms for realizing the quantum anomalous Hall effect (QAHE), where magnetism is usually caused by d orbitals of transition metals. Here we propose that a square lattice can host three magnetic topological states, including the fully spin-polarized nodal loop semimetal, QAHE and the topologically trivial ferromagnetic semiconductor, in terms of the symmetry and k · p model analyses that are material independent. A phase diagram is presented. We further show that the above three magnetic topological states can indeed be implemented in the two-dimensional (2D) materials ScLiCl₅, LiScZ₅ (Z=Cl, Br) and ScLiBr₅, respectively. The ferromagnetism in these 2D materials is microscopically revealed from p electrons of halogen atoms. This present study opens a door to explore the exotic topological states as well as quantum magnetism from p-orbital electrons by means of the material-independent approach.

[Feasibility of echocardiography-guided repeated intraventricular blood sampling in mice]

Objective: To investigate the feasibility of echocardiography-guided closed-chest repeated intraventricular blood sampling in mice, and to clarify the maximum blood volume that can be collected by this method, and whether the method can be used for long-term repeated blood collection in mice. Methods: Twenty-four male C57BL/6J mice (10-14 weeks old) were divided into the terminal experiment group (n=4, for investigating the maximum blood amount that could be sampled at one time), the repeated 0.5 ml blood collection group (n=10, sampling 0.5 ml whole blood each time, once every two days for consecutive 4 weeks), and the repeated 0.75 ml blood collection group (n=10, sampling 0.75 ml whole blood each time, once every two days for consecutive 4 weeks). High-frequency echocardiography was used to display the largest section of the left ventricle, guiding the insulin syringe needle through the thorax into the left ventricle for blood collection. In the repeated 0.5 ml blood collection group, echocardiography was used to detect the cardiac structure and function before blood collection, three minutes after blood collection, and one week after the last (the 14th) blood collection. Results: We successfully performed echocardiography-guided closed-chest intraventricular blood sampling, with an average operating time (88±19)s per mouse, and a maximum blood volume (1.43±0.11)ml per mouse. In the repeated 0.5 ml blood collection group, heart rate, left ventricular ejection fraction, left ventricular fractional shortening, left ventricular end-diastolic dimension and left ventricular posterior wall end-diastolic thickness remained uncganged before the first blood collection and after 4 weeks of repeated blood collection (all P>0.05). No death in the repeated 0.5 ml blood collection group. However, in the 0.75 ml blood collection group, two mice died before the end point. Conclusions: The echocardiography-guided closed-chest intraventricular blood sampling is a safe, minimally invasive, convenient and efficient method, and can be used repeatedly for long-term blood collection in mice.

Abstract P3-10-09: The association age-related parity and HER2 over-expression in breast cancer

Backgrounds

Reproductive factors, such as age at menarche, parity, age at first birth, and breast feeding, are known to be associated with risk of breast cancer. Recent studies show the association between the reproductive factors and the molecular subtypes of breast cancer, especially in luminal-like subtypes. Nulliparity is known a risk factor of breast cancer, multiparity is considered a protective factor. However, pregnancy associated breast cancers show the high expression of HER2, Therefore, we hypothesized the number of birth (multiparity) is correlated with the over-expression of HER2.

Methods

We reviewed the database of 2,594 breast cancer patients were over 20 years of age, diagnosed between January 2000 and April 2017 at Korea University of Anam Hospital, Seoul, Korea. According the number of birth, nulliparous (the number of birth = 0; 271 patients), primiparous (the number of birth = 1; 420 patients) and multiparous (the number of birth≥2; 1,903 patients) groups were classified.

Results

The median age (range) of nulliparous, primiparous and multiparous groups was 43 (22-77), 48 (27-87) and 51 (26-86) years (P&lt;0.001). In univariate analysis, the number of birth was associated with the expression of ER and HER2, nulliparous patients showed higher ER positivity (P=0.013) and multiparous patients showed higher HER2 overexpression (P=0.048). There was no association with PR and Ki-67 level. In logistic regression with age, the parity was negative correlation with ER positivity (OR 0.83, 95% CI 0.72-0.95, P=0.010) and positive correlation with HER2 overexpression (OR1.18, 95% CI 1.02-1.36, P=0.021) P=0.009) and multiparity was higher HER2 overexpression (OR 1.41, 95% CI 1.02-1.94, P=0.033). By subgroup analysis with menopausal status, there was statistically significance in only premenopausal women, not in postmenopausal women. In premenopausal women, the parity was negatively associated with ER positivity (OR 0.78, 95%CI 0.64-0.94, P=0.010) and multiparity was associated with HER2 overexpression (OR 1.72, 95%CI 1.12-2.63, P=0.013), there was no difference in HER2 overexpression between nulliparous and primiparous patients.

Conclusion

Parity was associated with ER and HER2 expression, multiparous patients were associated with ER negativity and HER2 overexpression, especially in premenopausal women. This suggests that pregnancy could affect risk of breast cancer, especially in HER2 positive breast cancer subtype (ER- HER2+ tumors), before menopause. We need further investigation and evaluation.

Citation Format: Bae SY, Kim J, You JY, Jung SP, Bae JW. The association age-related parity and HER2 over-expression in breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-10-09.

Abstract P3-01-12: Withdrawn

This abstract was withdrawn by the authors.

Abstract P6-08-09: Incidence and risk factors for congestive heart failure in early breast cancer received anthracycline and/or trastuzumab; big-data analysis of Korean health insurance review and assessment service database

Background: Anthracycline (AC) and/or trastuzumab (T) are the most commonly used for neo-/adjuvant therapy for early breast cancer. However, use of those regimens are limited owing to congestive heart failure (CHF). Although reported incidence from pivotal trials is very low and acceptable, no big data-based population study has not been conducted in Koreans yet. The aim of this study was to analyze the incidence, time to occurrence, and risk factors for CHF in patients with early breast cancer, who were treated with AC and/or T therapy, in Korea.

Methods: We used the Health Insurance Review and Assessment Service database and included women with no prior history of CHF who were aged &gt;19 years and diagnosed as having early breast cancer between 2007 and 2016. Only patients who had received breast cancer surgery and AC and/or T therapy were included. Patients with metastatic cancer codes were excluded.

Result: In total, 86,086 patients were included for this analysis. The incidence and median time to occurrence of CHF according to chemotherapy type were, 3.27% and 683.5 days in the AC only group, 6.39% and 374 days in the AC followed by T group, and 4.43% and 286 days in the T with or without non-AC group, respectively.

The multivariate Cox regression analysis revealed that the adjusted hazard ratio (HR) for CHF was increased with older age; in those aged ≥65 years versus &lt;50 years (HR, 2.79; 95% confidence interval [CI], 2.50–3.12). The HR in the AC followed by T group was significantly higher than that in the AC only group (HR, 2.21; 95% CI, 2.05-2.37). The T with or without non-AC group also showed a significantly higher HR than the AC only group (HR, 1.67; 95% CI, 1.37-2.04). CCI scores of ≥2 were significant predictors of CHF; score 2 versus 0 (HR, 1.30; 95% CI, 1.18-1.45), and score ≥3 versus 0 (HR, 1.87; 95% CI, 1.69-2.06). In addition, preexisting medical conditions were significant predictors for CHF: hypertension (HR, 1.58; 95% CI, 1.45-1.72), diabetes (HR, 1.17; 95% CI, 1.07-1.28), and ischemic heart disease (HR, 1.60; 95% CI, 1.45-1.76).

Conclusion: This is the first big data-based population study in Korea on the development of CHF after treatment with AC and/or T. The overall incidence of CHF was 3% to 6%, with a median time to occurrence of 1 to 2 years. Adjusted HR increased with older age, AC followed by T therapy, CCI scores ≥2, and preexisting conditions.

Table 1. Incidence and median time to occurrence of congestive heart failure according to chemotherapy typeChemotherapy typeTotalCHF event (%)Median time to occurenceAC only66,6992,182 (3.27%)683.5AC followed by T17,0621,090 (6.39%)374T ± non-AC2,325103 (4.43%)286

Table 2. Cox proportional hazards model for congestive heart failure, adjusted for age, chemotherapy type, and Charlson comorbidity index scoreVariableP-valueHR95% CIAge (ref &lt;50 years)   50-64 years&lt;0.00011.541.43-1.66≥65 years&lt;0.00012.792.50-3.12Chemotherapy type (ref AC only)   AC folloewed by T&lt;0.00012.212.05-2.37T ± non-AC&lt;0.00011.671.37-2.04Charlson comorbidity index score (ref 0)   10.12061.080.98-1.192&lt;0.00011.301.18-1.45≥3&lt;0.00011.871.69-2.06

Citation Format: Choi JY, Cho EY, Lee JW, Kim JW, Choi YJ, You JY, Bae SY, Jung SP, Cho KR, Park KH. Incidence and risk factors for congestive heart failure in early breast cancer received anthracycline and/or trastuzumab; big-data analysis of Korean health insurance review and assessment service database [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-08-09.

[Anterior versus posterior approach for multilevel cervical spondylotic myelopathy: a meta-analysis]

OBJECTIVE

To assess the clinical effectiveness and safety of anterior versus posterior approach for multilevel cervical spondylotic myelopathy.

METHODS

The following databases were searched: the Cochrane Library, PubMed, EM base, OVID, CBM, Wanfang Data, CNKI. Relevant journals were manually searched for randomized controlled trials or clinical controlled trials(CCTs) that investigated the clinical effectiveness and safety of anterior and posterior approach for multilevel cervical spondylotic myelopathy. Two reviewers independently screened the literature according to inclusion and exclusion criteria, extracted the data, and assessed the methodological quality of included studies. Meta-analysis was performed by using RevMan 5.2 software.

RESULTS

Eight CCTs, involving 1 151 patients, were included. Significant differences were found between anterior and posterior approach with respect to complications, OR=2.19, 95%CI (1.50, 3.19), P<0. 000 1; and neural recovery rate, WMD=11.04, 95% CI(0.60, 21.47), P=0.04 . In addition, there were no significant differences in preoperative JOA scores, WMD=0.13, 95% CI (-0.20, 0.46), P=0. 44; postoperative JOA scores, WMD=0.45, 95% CI (-0.10, 1.00), P=0.11; operation time, WMD=39.43, 95% CI(-5.92, 84.78), P=0.09; and amount of intraoperative bleeding, WMD=5.46, 95% CI(-96.65, 107.58), P=0. 92).

CONCLUSIONS

There are no significant differences between anterior and posterior approach for multilevel cervical spondylotic myelopathy in the recovery of neural function of the spinal cord, operation time and intraoperative bleeding. However, posterior appreach showed fewer complications than anterior appreach.

Abstract P1-01-19: Role of axillary clearance with tumor positive sentinel node in mastectomy group: Is the results of ACOSOG Z0011 trial adaptable to mastectomy patient?

Background: Recent data from ACOSOG Z0011 trial or AMAROS trial suggest that axillary lymph node dissection(ALND) may be unnecessary for patients with positive sentinel lymph node biopsy(SLNB) receiving breast conserving surgery(BCS) with irradiation. However, consensus statements and guidelines until recently recommended that patients with mastectomy and tumor positive sentinel node undergo completion ALND. In this preliminary study, we compared these patients who did not undergo ALND with the patients who received BCS with SLNB only and irradiation and we analyzed the locoregional recurrence rate to show no differences of outcomes between two groups.

Method: We identified 6,163 women with invasive breast cancer who underwent surgical resection at the National Cancer Center (Goyang,Gyeonggi-do,Korea) between January 2000 to December 2011. Clinico-pathological data obtained from prospective collecting medical database of our institution were analyzed retrospectively. The mastectomy with positive SLNB group was 47 patients and BCS with positive SLNB and irradiation group was 172 patients. The primary end point was loco-regional recurrence rate.

Result : Clinical and tumor characteristics were similar between two groups except T stage and receptor status. The mean tumor size was 5.5cm with mastectomy group and 3.5cm with BCS group. The median number of nodes removed was three. There was not a single case of locoregional recurrence in both groups. At a median follow-up of 53.5 months (last follow-up, May 2013), 5-year overall survival was 85.7% with mastectomy and 97.3% with BCS group.

Conclusion : In our study, there was no case of locoregional recurrence as above. This results lend weight to the argument that SLNB without ALND may be reasonable management for selected patients with appropriate surgery and adjuvant systemic therapy. This study can be regarded as a preliminary study with a sufficient value despite of the prognosis showed some statistical differences between two groups. It resides in the difference of initial stage of patients of two groups. We will present additional data compared with the mastectomy with axillary clearance group at the meeting.

Acknowledgement This work was supported by grant from the National Cancer Center Korea (1210331-2).

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-01-19.

Abstract P3-08-14: Could the preoperative systemic therapy be a risk factor for breast cancer-related lymphedema in stage II/III breast cancer?

Background: The breast cancer-related lymphedema (LE) has been known to be closely related to axillary lymph nodes dissection (ALND), chemotherapy, and radiation therapy. In this study, we evaluated whether the sequence of systemic chemotherapy and surgery could be a predictive factor in stage II/III breast cancer.

Methods and Materials: A total of 867 patients with stage II/III breast cancer, who underwent curative surgery with adequate systemic therapy from 2004 to 2009, were retrospectively analyzed. Adjuvant chemotherapy (ACT) was performed in 571 patients (65.9%) and preoperative systemic chemotherapy (PSC) in 296 (34.1%). We evaluated the incidence of LE by clinicopathologic factors and treatments.

Results: At a median follow-up of 5.1 years (range, 3.0-8.3 years), 360 patients (41.5%) had experienced LE, 244 patients have retained LE (permanent LE), and 116 patents were normalized. The overall 5-year cumulative incidence of LE was 17%. LE occurred in 188 patients (32.9%) in patients with ACT, 172 patients (58.1%) with PSC (P&lt;0.001), permanent LE in 121 (21.2%) with ACT, 123 (41.6%) with PSC (P&lt;0.001), respectively. Multivariate analysis showed that PSC (hazard ratio [HR], 1.65; P&lt;.001), radiotherapy (HR, 2.24; P&lt;0.01), ALND (HR, 1.41; P = 0.04), and nodal stage (HR, 1.93; P = 0.04) were independent risk factors for LE occurrence. For the permanent LE, PSC (HR, 1.44; P = 0.05), radiotherapy (HR, 2.79; P&lt;0.01), ALND (HR, 1.77; P&lt;0.01), and nodal stage (HR, 3.01; P = 0.02) showed the associations.

Conclusions: The risk factors associated with LE were advanced stage, ALND and radiotherapy. PSC was one of predictors for transients LE. However, further evaluation should be done whether it is a risk factor for permanent LE.

This research was supported by National Cancer Center Grant NCC-1210181-2 by the National Cancer Center, Republic of Korea.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-08-14.

Helicobacter pylori in dental plaque and saliva

BACKGROUND

About half of the world population is infected with H. pylori, but the transmission and the source of this infection are still unclear. Recently, dental plaque (DP) and saliva have been implicated as possible sources of H. pylori infection. This study was done to investigate the detection rates of H. pylori in the DP and saliva by use of PCR depending on H. pylori infection state of gastric mucosa.

METHODS

In 46 subjects, gastric H. pylori colonization was evaluated with CLO test, microscopy of Gram stained mucosal smear, culture and histology after modified Giemsa staining in the antrum and body, respectively. A patient was regarded as H. pylori positive if one or more of the four aforementioned test methods demonstrated H. pylori colonization of the gastric mucosa. For detection of H. pylori in the DP and saliva, PCR assay was done with ET4-U and ET4-L primers. To estimate the sensitivity and specificity of this PCR, H. pylori positivity was evaluated in the antrum and body, separately.

RESULTS

The sensitivity of mucosal PCR was 50.0% (27/54) and the specificity 86.8% (33/38). When a subject was regarded as H. pyloi positive, if either antrum or body mucosal H. pylori was is positive, the positive rate of mucosal PCR was 62.1% (18 subjects) in the 29 H. pylori-positive and 17.6% (3 subjects) in the 17 H. pylori-negative subjects. DP PCR was positive in 2 of 29 H. pylori-positive subjects (6.9%) and none in the 17 H. pylori-negative (0%). Saliva PCR was positive in 4 of 14 H. pylori-positive subjects (28.6%) and none of 6 H. pylori-negative (0%).

CONCLUSION

The detection rates of H. pylori in DP and saliva by PCR were rather low, 6.9% and 28.6%, respectively, and these rates might have been underestimated by low sensitivity of the PCR method used in this study. However, the results that H. pylori was found in the DP and saliva suggest that the oral cavity can perform a role as a reservoir of H. pylori in Korea.