Electromagnetic spectroscopy of normal breast tissue specimens obtained from reduction surgeries: comparison of optical and microwave properties.

Techniques utilizing electromagnetic energy at microwave and optical frequencies have been shown to be promising for breast cancer detection and diagnosis. Since different biophysical mechanisms are exploited at these frequencies to discriminate between healthy and diseased tissue, combining these two modalities may result in a more powerful approach for breast cancer detection and diagnosis. Toward this end, we performed microwave dielectric spectroscopy and optical diffuse reflectance spectroscopy measurements at the same sites on freshly excised normal breast tissues obtained from reduction surgeries at the University of Wisconsin Hospital, using microwave and optical probes with very similar sensing volumes. We found that the microwave dielectric constant and effective conductivity are correlated with tissue composition across the entire measurement frequency range (|r| approximately 0.5-0.6, p<0.01) and that the optical absorption coefficient at 460 nm and optical scattering coefficient are correlated with tissue composition (|r| approximately 0.4-0.6, p<0.02). Finally, we found that the optical absorption coefficient at 460 nm is correlated with the microwave dielectric constant and effective conductivity (r=-0.55, p<0.01). Our results suggest that combining optical and microwave modalities for analyzing breast tissue samples may serve as a crosscheck and provide complementary information about tissue composition.

A large-scale study of the ultrawideband microwave dielectric properties of normal, benign and malignant breast tissues obtained from cancer surgeries.

The development of microwave breast cancer detection and treatment techniques has been driven by reports of substantial contrast in the dielectric properties of malignant and normal breast tissues. However, definitive knowledge of the dielectric properties of normal and diseased breast tissues at microwave frequencies has been limited by gaps and discrepancies across previously published studies. To address these issues, we conducted a large-scale study to experimentally determine the ultrawideband microwave dielectric properties of a variety of normal, malignant and benign breast tissues, measured from 0.5 to 20 GHz using a precision open-ended coaxial probe. Previously, we reported the dielectric properties of normal breast tissue samples obtained from reduction surgeries. Here, we report the dielectric properties of normal (adipose, glandular and fibroconnective), malignant (invasive and non-invasive ductal and lobular carcinomas) and benign (fibroadenomas and cysts) breast tissue samples obtained from cancer surgeries. We fit a one-pole Cole-Cole model to the complex permittivity data set of each characterized sample. Our analyses show that the contrast in the microwave-frequency dielectric properties between malignant and normal adipose-dominated tissues in the breast is considerable, as large as 10:1, while the contrast in the microwave-frequency dielectric properties between malignant and normal glandular/fibroconnective tissues in the breast is no more than about 10%.

A large-scale study of the ultrawideband microwave dielectric properties of normal breast tissue obtained from reduction surgeries.

The efficacy of emerging microwave breast cancer detection and treatment techniques will depend, in part, on the dielectric properties of normal breast tissue. However, knowledge of these properties at microwave frequencies has been limited due to gaps and discrepancies in previously reported small-scale studies. To address these issues, we experimentally characterized the wideband microwave-frequency dielectric properties of a large number of normal breast tissue samples obtained from breast reduction surgeries at the University of Wisconsin and University of Calgary hospitals. The dielectric spectroscopy measurements were conducted from 0.5 to 20 GHz using a precision open-ended coaxial probe. The tissue composition within the probe's sensing region was quantified in terms of percentages of adipose, fibroconnective and glandular tissues. We fit a one-pole Cole-Cole model to the complex permittivity data set obtained for each sample and determined median Cole-Cole parameters for three groups of normal breast tissues, categorized by adipose tissue content (0-30%, 31-84% and 85-100%). Our analysis of the dielectric properties data for 354 tissue samples reveals that there is a large variation in the dielectric properties of normal breast tissue due to substantial tissue heterogeneity. We observed no statistically significant difference between the within-patient and between-patient variability in the dielectric properties.

Resolving ASCUS without recourse to HPV testing: manual reprocessing of residual automated liquid-based cytology (ALBC) material using manual liquid-based cytology (MLBC).

We show that residual cell material from ThinPrep PapTest (Cytyc Corporation, Boxborough, MA) atypical squamous-cells of undetermined significance (ASCUS) cases may be manually reprocessed to triage women into actionable diagnostic categories (HSIL, LSIL, and Negative). Material remaining from each of 358 ThinPrep ASCUS cases was manually reprocessed as two slides, labeled "A" and "B." Interobserver agreement between case contributors (CCs) and three sequential reviewers (SRs) was analyzed with 186 cases (Study 1), and diagnostic reproducibility between SRs was examined with an additional 172 cases (Study 2). In Study 1, CCs classified 33% of cases as LSIL or greater, SRs classified 60% as LSIL or greater, and there was 58% diagnostic agreement between CCs and SRs. No "Negative" case assignment by one group afforded an "HSIL" assignment by the complementary group. In Study 2, there was 95% agreement between SRs A slide and B slide diagnoses with 54% of A slides and 55% of B slides classified as LISL or greater. Again, no "Negative" case assignment to one slide afforded an "HSIL" assignment to the complementary slide. Overall, 12.6% of the 358 cases showed HSIL, and all HSILs by one observer group were ASCUS or greater by the complementary observer group. Using manual reprocessing beyond the 21-day specimen outdate for HPV testing by the Hybrid Capture II High Risk HPV test (HR-HCII; Digene Corporation, Beltsville, MD), many ThinPrep ASCUS cases were reclassified as LSIL or HSIL. The 12.6% HSIL proportion of this study approximated the 11.5% CIN 2 or greater proportion of the ALTS ASCUS arm. Similar to ALTS, manual liquid-based cytology (MLBC) would have referred nearly 60% of women to colposcopy for a definitive diagnosis of HSIL or LSIL without resorting to HPV testing. These data demonstrate that many cases of automated liquid-based cytology (ALBC)-diagnosed ASCUS represent unrecognized SIL, which is present in the ALBC specimen vial at the time the ASCUS diagnosis is rendered.