Outcomes of male patients attending the symptomatic breast unit: adherence to local and national imaging guidelines and effectiveness of clinical examination and imaging in detecting male breast cancer.

AIM: To review outcomes of male patients attending the breast unit, evaluate effectiveness of imaging and examination in detecting breast cancer and review adherence to guidelines for male breast imaging. MATERIALS AND METHODS: A retrospective review was undertaken of male patients attending Cambridge Breast Unit from 1 January 2015 to 31 December 2019. Patient electronic records and imaging were reviewed to establish demographics, clinical findings, imaging, biopsy, and pathology outcomes. RESULTS: Of 1,362 male patients attending the breast unit, 1,028 (75%) had imaging performed. Biopsy was performed in 41 men (3%), with 14 cancers diagnosed (1%). Clinical examination showed 42.7% sensitivity, 99.6% specificity, 54.6% positive predictive value (PPV) and 99.4% negative predictive value (NPV) for detection of cancer. Mammogram demonstrated 84.6% sensitivity, 99.4% specificity, 69.8% PPV, and 99.8% NPV for detection of malignancy. Ultrasound demonstrated 78.6% sensitivity, 98.9% specificity, 73.3% PPV and 99.2% NPV for detection of cancer. Forty-one percent of patients <40 years and 51% < 50 years were imaged, who according to local and Royal College of Radiologists (RCR) guidelines did not require imaging based on age and clinical score. CONCLUSION: Male patients account for a small proportion of referrals to the breast unit but generate significant workload. Imaging protocols, incorporating clinical score and age cut-off at 40 years remains robust for detecting malignancy. Clinician awareness of the imaging protocol, and close liaison with radiologists is essential to minimise additional radiology workload.

Unprovoked venous thromboembolism in women over 40: is screening for occult malignancy with mammography and abdominopelvic CT of benefit?

AIM: To determine imaging and pathological outcomes in cases of unprovoked venous thromboembolism (VTE) referred for mammogram. A secondary objective was to elucidate outcomes of abdominopelvic computed tomography (CT) imaging performed in this cohort. MATERIALS AND METHODS: A retrospective review of mammograms performed in cases of unprovoked VTE was undertaken from January 2016 to September 2019. Patient notes and imaging were reviewed to establish patient demographics, additional imaging required, biopsies performed, pathology findings, and eventual outcomes. Cases were reviewed to determine if concurrent CT abdomen/pelvis was performed to screen for malignancy. Outcomes of CT were recorded. RESULTS: One hundred and thirty-nine women attended for screening mammogram following unprovoked VTE during the study period. Mean patient age was 68 years (range 42-89 years). Fourteen women (10%) were recalled for further breast imaging, with two cases of confirmed malignancy (1.4%). Of the 139 women, 118 also underwent CT imaging, with 18 patients (15%) recalled for further investigations. Two (1.7%) cases of malignancy (lung and ovarian) were identified. CONCLUSION: A low cancer detection rate was demonstrated in women undergoing mammography or CT following unprovoked VTE. In addition, the high number of false-positive findings and need for additional investigations questions the value of screening in this setting. Based on these findings, Cambridge Breast Unit has ceased mammographic and abdominopelvic CT imaging in women with unprovoked VTE, anticipating the newly updated National Institute for Health and Care Excellence (NICE) guidelines.

The value of routine screening mammography in women aged 35-39 years in a symptomatic breast unit.

AIM: To determine the breast cancer detection rate at routine bilateral screening mammography in women aged 35-39 years attending a symptomatic breast clinic, in women of population-risk profile with a normal clinical examination. METHODS AND MATERIALS: A retrospective analysis of all mammograms performed on patients aged 35-39 years at St James's Hospital from 2011-2015 was carried out. Patients with moderate or high familial risk of breast cancer, personal breast cancer history or chest radiation, males, general practitioner (GP) and internal hospital referrals, and those with abnormal clinical examinations were excluded. Included women had "normal", "benign", or undocumented examination findings. Results of imaging, including ultrasound and histopathological results, were recorded. Information was extracted from the hospital's electronic record systems. RESULTS: Of 4,087 patients aged 35-39 who had bilateral mammograms from 2011-2015, 2,148 patients were excluded from analysis. Of 1,939 included women, four (0.21%) were diagnosed with breast cancer confirmed at histology based on mammographic findings: two invasive ductal carcinoma (8 and 2 mm) and two ductal carcinoma in situ (DCIS; 4.5 mm high-grade DCIS and 2 mm low-grade DCIS). Other histological findings included two B3, 46 B2, and three B1 lesions. Overall, 115 biopsies were performed in this cohort; 55 (47.8%) were attributable to mammographic screening, producing a biopsy rate of 2.8% due to mammography alone. CONCLUSION: Per 1,000 women screened, 2.1 cases of cancer were detected. This figure would be below accepted international thresholds to undertake screening mammography and raises radiation protection issues. Additionally, a large number of benign biopsies were undertaken, with likely resultant psychological impact. Further studies could inform national guidance.

Optical fiber poling by induction: analysis by 2D numerical modeling.

Since their first demonstration some 25 years ago, thermally poled silica fibers have been used to realize device functions such as electro-optic modulation, switching, polarization-entangled photons, and optical frequency conversion with a number of advantages over bulk free-space components. We have recently developed an innovative induction poling technique that could allow for the development of complex microstructured fiber geometries for highly efficient χ(2)-based device applications. To systematically implement these more advanced poled fiber designs, we report here the development of comprehensive numerical models of the induction poling mechanism itself via two-dimensional (2D) simulations of ion migration and space-charge region formation using finite element analysis.

Determination of recall rates for assessment in high-risk women undergoing annual surveillance breast MRI.

AIM: To review all surveillance breast magnetic resonance imaging (MRI) examinations performed over a 6-year period at an Irish national centre to determine the recall rate, biopsy rate, and cancer-detection rates. MATERIALS AND METHODS: All breast MRI examinations performed for surveillance purposes in women at high risk of developing breast cancer between January 2009 and December 2014 were reviewed. The Breast Imaging-Reporting and Data System (BI-RADS) score for each MRI examination was determined, the type of additional imaging performed, and the method of biopsy, if performed, was recorded. Histology of the biopsy specimens was reviewed. RESULTS: Data for 715 women undergoing 1445 surveillance MRI examinations were identified. Of the examinations, 10.9% (157/1445) had MRI BI-RADS scores that required recall for further imaging and 6.3% (91/1445) required a biopsy. Recall rates were 14.2% (86/607) and 8.5% (71/838) in the prevalent and incident rounds, respectively. The overall cancer detection rate was 17 per 1000. CONCLUSION: The current UK guideline was not achieved and no studies to date have achieved the target of <7%. Aiming for this target could risk lowering the cancer-detection rate. The authors would suggest a target rate of <15% and <10% for the prevalent round and incident rounds, respectively.

Kerr nonlinear switching in a hybrid silica-silicon microspherical resonator.

A hybrid silicon-core, silica-clad microspherical resonator has been fabricated from the semiconductor core fiber platform. Linear and nonlinear characterization of the resonator properties have shown it to exhibit advantageous properties associated with both materials, with the low loss cladding supporting high quality (Q) factor whispering gallery modes which can be tuned through the nonlinear response of the crystalline core. By exploiting the large wavelength shift associated with the Kerr nonlinearity, we have demonstrated all-optical modulation of a weak probe on the timescale of the femtosecond pump pulse. This novel geometry offers a route to ultra-low loss, high-Q silica-based resonators with enhanced functionality.

Post traumatic Fat Embolism in Common Femoral Vein on CT.

Fat embolism syndrome usually occurs following trauma where fat globules from long bone fractures produce pulmonary, cerebral or cutaneous effects. This case illustrates the presence of macroscopic fat in the right common femoral vein secondary to a long bone fracture. This finding is rare but should be looked for on cross-sectional imaging to allow early, aggressive treatment of fat embolism syndrome.

Optical fiber poling by induction.

Conventional thermal poling methods require direct physical contact to internal fiber electrodes. Here, we report an indirect electrostatic induction technique using electrically floating wires inside the fiber combined with external electric fields that can allow for facile poling of complex microstructured fibers (MOFs) of arbitrarily long lengths. In combination with our unique ability to use liquid gallium electrodes, inducing second-order nonlinearities inside otherwise difficult to access multi-core or multi-hole MOFs now becomes entirely feasible and practical. The formation of a permanent second-order nonlinearity is unequivocally demonstrated by realizing quasi-phase-matched frequency doublers using periodic UV erasure methods in the induction-poled fibers. The second-order susceptibility created inside the fiber is driven by the potential difference established between the floating electrodes, which we calculate via numerical simulations.

Four-wave mixing and octave-spanning supercontinuum generation in a small core hydrogenated amorphous silicon fiber pumped in the mid-infrared.

An octave-spanning supercontinuum is generated in a hydrogenated amorphous silicon core fiber when pumped in the mid-infrared regime. The broadband wavelength conversion which extends from the edge of the telecommunications band into the mid-infrared (1.64-3.37 µm) is generated by four-wave mixing (FWM) and subsequent pulse break-up, facilitated by the high material nonlinear figure of merit and the anomalous dispersion of the relatively small 1.7 µm diameter core fiber. The FWM sidebands and corresponding supercontinuum can be tuned through the pump parameters, and show good agreement with the predicted phase-matching curves for the fiber.

Nonlinear transmission properties of hydrogenated amorphous silicon core fibers towards the mid-infrared regime.

The nonlinear transmission properties of hydrogenated amorphous silicon (a-Si:H) core fibers are characterized from the near-infrared up to the edge of the mid-infrared regime. The results show that this material exhibits linear losses on the order of a few dB/cm, or less, over the entire wavelength range, decreasing down to a value of 0.29 dB/cm at 2.7µm, and negligible nonlinear losses beyond the two-photon absorption (TPA) edge ~ 1.7µm. By measuring the dispersion of the nonlinear Kerr and TPA parameters we have found that the nonlinear figure of merit (FOM(NL)) increases dramatically over this region, with FOM(NL) > 20 around 2µm and above. This characterization demonstrates the potential for a-Si:H fibers and waveguides to find use in nonlinear applications extending beyond telecoms and into the mid-infrared regime.

Systemic mirnas as potential biomarkers for malignancy.

MiRNAs are a class of short, endogenous, single-stranded RNA molecules that play a role in the regulation of gene expression. They have been shown to modulate a number of cellular processes including cell differentiation, growth and apoptosis and as a result have been implicated in carcinogenesis. They are detectable in tumour tissue, and altered expression levels have been identified in various cancer types. Of interest, miRNAs have recently been detected and identified to be dysregulated in the circulation of patients with breast cancer. The fact that a minimally invasive test can distinguish the presence or absence of disease illustrates the immense potential these molecules hold as predictive markers. This review serves to identify those systemic miRNAs that are upregulated or downregulated in malignancy and how treatment impacts on their circulating levels. In addition, this review questions the source of these small molecules in the bloodstream and how they may possibly play a role in the future detection of cancer as either prognostic or predictive markers.

Ultrafast wavelength conversion via cross-phase modulation in hydrogenated amorphous silicon optical fibers.

We present a characterization of the spectral modulation and wavelength shifting induced via cross-phase modulation (XPM) in a hydrogenated amorphous silicon (a-Si:H) core optical fiber. Pump-probe experiments using picosecond and femtosecond signal pulses are shown to be in good agreement with numerical simulations of the coupled nonlinear propagation equations. The large 10nm red-shifts obtained with the femtosecond probe pulses are attributed to the high Kerr nonlinearity of the a-Si:H material. Extinction ratios as high as 12 dB are measured for the conversion process at telecommunications wavelengths, indicating the potential for high-speed nonlinear optical control in a-Si:H fibers and waveguides.

The h index and the identification of global benchmarks for breast cancer research output.

The h index is used to assess an individual's contribution to the literature. This metric should not be employed to compare individuals across research areas; rather each subject should have its own baseline and standard. This work aimed to identify global bibliometric benchmarks for those involved in breast cancer research, and specifically, to describe the bibliographic characteristics of breast surgeons in the UK and Ireland. Authorship data was extracted from breast cancer related output from 1945 to 2008, as indexed in the Web of Science. Authors' publications, citations and h indexes were identified. The breast-related output of 277 UK and Irish breast surgeons was evaluated, and a citation report generated for each. Strong correlation was noted between the h index and number of publications (r = 0.642, P < 0.001) and number of total citations (r = -0.922, P < 0.001). The author with the highest h index is B Fisher (h index = 80). 23.0% of surgeons had not published original research pertaining to the breast; the remainder had together produced 2,060 articles, accounting for 59,002 citations. The top quartile was responsible for 83% of output; the 90th percentile was 20 publications. The range of h index values for the surgeons was 0-50, with a median h index returned of 3 (IQR 1-6); the 90th percentile was 13.5. This work has identified bibliometric benchmarks to which those involved in breast cancer research might aspire. Our findings suggest that there is need for wider involvement of surgeons in the research process and raises questions regarding the future of scientific breast surgery.

All-optical modulation using two-photon absorption in silicon core optical fibers.

All-optical modulation based on degenerate and non-degenerate two-photon absorption (TPA) is demonstrated within a hydrogenated amorphous silicon core optical fiber. The nonlinear absorption strength is determined by comparing the results of pump-probe experiments with numerical simulations of the coupled propagation equations. Subpicosecond modulation is achieved with an extinction ratio of more than 4 dB at telecommunications wavelengths, indicating the potential for these fibers to find use in high speed signal processing applications.

High index contrast semiconductor ARROW and hybrid ARROW fibers.

We investigate the guidance properties of two photonic crystal fibers that have been fabricated by filling the holes of a silica template with hydrogenated amorphous silicon inclusions. The first is an all-solid fiber that guides light via an antiresonant reflecting optical waveguiding mechanism and the second is only partially filled so that it guides light by a hybrid of modified total internal reflection and antiresonant reflecting optical waveguiding. It will be shown that, by selectively filling the silica template to leave an unfilled internal ring of holes, the fiber's confinement loss can be reduced significantly. This novel fiber design in which the light guided in the silica core can be modified by the semiconductor cladding provides a route to integrating functional semiconductor fibers with existing silica fiber infrastructures.

Tapered silicon optical fibers.

The tapering of silicon optical fibers is demonstrated using a fusion splicer. The silicon fibers are fabricated using a high pressure chemical deposition technique to deposit an amorphous silicon core inside a silica capillary and the tapering is performed in a separate post-process. Optical and material characterization has revealed a smooth transition region leading to a uniform tapered waist that are both simultaneously crystallized to yield a solid polysilicon core. The strong mode confinement and low taper loss measured in the silicon fibers verifies this tapering approach for the fabrication of structures with nanoscale core dimensions.

Nonlinear transmission properties of hydrogenated amorphous silicon core optical fibers.

The nonlinear properties of a low loss hydrogenated amorphous silicon core fiber have been characterized for transmission of high power pulses at 1540 nm. Numerical modelling of the pulse propagation in the amorphous core material was used to establish the two-photon absorption, free-carrier absorption and the nonlinear refractive index, which were found to be larger than the values typical for crystalline silicon. Calculation of a nonlinear figure of merit demonstrates the potential for these hydrogenated amorphous silicon core fibers to be used in nonlinear silicon photonics applications.

Large mode area silicon microstructured fiber with robust dual mode guidance.

A silicon microstructured fiber has been designed and fabricated using a pure silica photonic bandgap guiding fiber as a 3D template for materials deposition. The resulting silicon fiber has a micron sized core but with a small core-cladding index contrast so that it only supports two guided modes. It will be shown that by using the microstructured template this fiber exhibits a number of similar guiding properties to the more traditional index guiding air-silica structures. The large mode areas and low optical losses measured for the silicon microstructured fiber demonstrate its potential to be integrated with existing fiber infrastructures.