The relationship between breast asymmetry, breast size and the occurrence of breast cancer

Automated Computer-Assisted Medical Decision-Making System Based on Morphological Shape and Skin Thickness Analysis for Asymmetry Detection in Mammographic Images

Breast cancer is a significant health concern for women, emphasizing the need for early detection. This research focuses on developing a computer system for asymmetry detection in mammographic images, employing two critical approaches: Dynamic Time Warping (DTW) for shape analysis and the Growing Seed Region (GSR) method for breast skin segmentation. The methodology involves processing mammograms in DICOM format. In the morphological study, a centroid-based mask is computed using extracted images from DICOM files. Distances between the centroid and the breast perimeter are then calculated to assess similarity through Dynamic Time Warping analysis. For skin thickness asymmetry identification, a seed is initially set on skin pixels and expanded based on intensity and depth similarities. The DTW analysis achieves an accuracy of 83%, correctly identifying 23 possible asymmetry cases out of 20 ground truth cases. The GRS method is validated using Average Symmetric Surface Distance and Relative Volumetric metrics, yielding similarities of 90.47% and 66.66%, respectively, for asymmetry cases compared to 182 ground truth segmented images, successfully identifying 35 patients with potential skin asymmetry. Additionally, a Graphical User Interface is designed to facilitate the insertion of DICOM files and provide visual representations of asymmetrical findings for validation and accessibility by physicians.

Risk Analysis of Breast Cancer by Using Bilateral Mammographic Density Differences: A Case-Control Study

The identification of risk factors helps radiologists assess the risk of breast cancer. Quantitative factors such as age and mammographic density are established risk factors for breast cancer. Asymmetric breast findings are frequently encountered during diagnostic mammography. The asymmetric area may indicate a developing mass in the early stage, causing a difference in mammographic density between the left and right sides. Therefore, this paper aims to propose a quantitative parameter named bilateral mammographic density difference (BMDD) for the quantification of breast asymmetry and to verify BMDD as a risk factor for breast cancer. To quantitatively evaluate breast asymmetry, we developed a semi-automatic method to estimate mammographic densities and calculate BMDD as the absolute difference between the left and right mammographic densities. And then, a retrospective case-control study, covering the period from July 2006 to October 2014, was conducted to analyse breast cancer risk in association with BMDD. The study included 364 women diagnosed with breast cancer and 364 matched control patients. As a result, a significant difference in BMDD was found between cases and controls (P < 0.001) and the case-control study demonstrated that women with BMDD > 10% had a 2.4-fold higher risk of breast cancer (odds ratio, 2.4; 95% confidence interval, 1.3-4.5) than women with BMDD ≤ 10%. In addition, we also demonstrated the positive association between BMDD and breast cancer risk among the subgroups with different ages and the Breast Imaging Reporting and Data System (BI-RADS) mammographic density categories. This study demonstrated that BMDD could be a potential risk factor for breast cancer.

Experience of Pain and Unpleasantness during Mammography Screening: A Cross-Sectional Study on the Roles of Emotional, Cognitive, and Personality Factors

BACKGROUND

Breast cancer is the most frequent cause of malignant tumors among women worldwide. Its successful prevention depends on the degree of participation in screening programs, which can be influenced by psychological factors, including fear.

METHOD

A cross-sectional study was conducted according to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement. Twenty-six healthy women aged 50-69 years took part in this study, all of whom were summoned for routine mammography screening and were randomly selected. Prior mammography screening, breast pain intensity, unpleasantness (visual analog scale), and psychological (catastrophizing, state anxiety, and fear of pain) and personality (neuroticism, psychoticism, and extraversion) variables were evaluated. Pain, unpleasantness, and state anxiety were further evaluated pre- and post-mammography screening.

RESULTS

During the mammography screening, pain and unpleasantness levels were higher than those observed pre- and post-screening. Residual unpleasantness remained post-screening. State anxiety was positively associated with pain, and psychoticism with unpleasantness, as reported by participants during the mammography screening.

CONCLUSIONS

Anxiety levels influence the pain experienced in association with the mammography procedure. Women subjected to mammography screenings might benefit from relaxation strategies aimed at reducing anxiety to pre-mammography levels and, by extension, pain and unpleasantness during mammography. The inclusion of these strategies in breast cancer prevention campaigns could improve the rates of mammography reattendance, and therefore, benefit cancer prevention efforts.

Breast Fluctuating Asymmetry in Women with Macromastia/Gigantomastia

BACKGROUND

A number of studies have reported breasts have high fluctuating asymmetry (FA:|Right-Left|), suggesting that they contain evolutionary and clinical information (e.g., high FA correlates with breast cancer risk). Here we focus on breast FA in women with a wide range of breast sizes, including participants with macromastia and/or gigantomastia.

MATERIAL AND METHODS

The sample included 65 women (mean age 33.97 ± 12.1 years). Thirty were randomly selected students and/or patients who regarded their breast size as small, normal or average and who had not undergone or intended to have any breast surgery. The remainder (n = 35) were qualified for breast reduction due to macromastia and/or gigantomastia. In all participants we measured/calculated weight, height and BMI, as well as took chest photographs. Breast volumes and nipple areola complex FAs were evaluated in a specifically-designed software.

RESULTS

Breast size significantly positively correlated with breast volume FA in all women (t = 5.17, p < 0.0001) and in women with macromastia/gigantomastia (t = 2.32, p = 0.027). All nipple location FAs correlated positively with breast size.

CONCLUSIONS

In women with different breast sizes, breast size correlates with FA calculated from breast volume and nipple location FAs. In women with macromastia and/or gigantomastia, breasts present higher FA than "normal" breasts. This observation may give a rationale for earlier and more frequent prophylactic breast imaging in women with macromastia and/or gigantomastia.

Right-left digit ratios, a novel form of asymmetry: Patterns of instability in children and relationships to platelet counts and hospitalization in adults with COVID-19

High right minus left (R-L) asymmetry of digit ratios has been reported to be linked to hospitalization for COVID-19. Here we examined the developmental patterns of this novel form of asymmetry in children and further explored their relationships to platelet counts and hospitalization for COVID-19 in adult patients. We considered ratios calculated from four digits (2D, 3D, 4D, 5D) in: (i) a sample of healthy participants aged 2 years to 18 years (n = 680, 340 males) and (ii) 96 adult patients (42 males) hospitalized for COVID-19 and 100 controls (53 males). The protocol for (ii) included a questionnaire and laboratory test results. In sample (i) of the six unsigned digit ratio asymmetries, those which included 5D had the highest mean asymmetry with the greatest between-individual variation and they were unstable over the age range of 2 years to 18 years. In sample (ii) patients showed higher asymmetries than controls in four ratios (2D:4D, 2D:5D, 3D:5D, 4D:5D) and a sum of asymmetries of the two independent ratios (2D:4D+3D:5D) correlated positively with platelet counts and hospitalization. Conclusion: Means and SDs of digit ratio asymmetry that include the 5th digit are high and age-unstable. Digit ratio asymmetry, particularly 5th digit ratio asymmetry and a composite measure of 2D:4D + 3D:5D asymmetry, may be positively linked to high platelet counts in COVID-19 patients and to an elevated risk of hospitalization.

The evolution of perennially enlarged breasts in women: a critical review and a novel hypothesis

The possession of permanent, adipose breasts in women is a uniquely human trait that develops during puberty, well in advance of the first pregnancy. The adaptive role and developmental pattern of this breast morphology, unusual among primates, remains an unresolved conundrum. The evolutionary origins of this trait have been the focus of many hypotheses, which variously suggest that breasts are a product of sexual selection or of natural selection due to their putative role in assisting in nursing or as a thermoregulatory organ. Alternative hypotheses assume that permanent breasts are a by-product of other evolutionary changes. We review and evaluate these hypotheses in the light of recent literature on breast morphology, physiology, phylogeny, ontogeny, sex differences, and genetics in order to highlight their strengths and flaws and to propose a coherent perspective and a new hypothesis on the evolutionary origins of perennially enlarged breasts in women. We propose that breasts appeared as early as Homo ergaster, originally as a by-product of other coincident evolutionary processes of adaptive significance. These included an increase in subcutaneous fat tissue (SFT) in response to the demands of thermoregulatory and energy storage, and of the ontogenetic development of the evolving brain. An increase in SFT triggered an increase in oestradiol levels (E2). An increase in meat in the diet of early Homo allowed for further hormonal changes, such as greater dehydroepiandrosterone (DHEA/S) synthesis, which were crucial for brain evolution. DHEA/S is also easily converted to E2 in E2-sensitive body parts, such as breasts and gluteofemoral regions, causing fat accumulation in these regions, enabling the evolution of perennially enlarged breasts. Furthermore, it is also plausible that after enlarged breasts appeared, they were co-opted for other functions, such as attracting mates and indicating biological condition. Finally, we argue that the multifold adaptive benefits of SFT increase and hormonal changes outweighed the possible costs of perennially enlarged breasts, enabling their further development.

Left-right breast asymmetry and risk of screen-detected and interval cancers in a large population-based screening population

OBJECTIVES

To assess the associations between automated volumetric estimates of mammographic asymmetry and breast cancers detected at the same ("contemporaneous") screen, at subsequent screens, or in between (interval cancers).

METHODS

Automated measurements from mammographic images (N = 79,731) were used to estimate absolute asymmetry in breast volume (BV) and dense volume (DV) in a large ethnically diverse population of attendees of a UK breast screening programme. Logistic regression models were fitted to assess asymmetry associations with the odds of a breast cancer detected at contemporaneous screen (767 cases), adjusted for relevant confounders.Nested case-control investigations were designed to examine associations between asymmetry and the odds of: (a) interval cancer (numbers of cases/age-matched controls: 153/646) and (b) subsequent screen-detected cancer (345/1438), via conditional logistic regression.

RESULTS

DV, but not BV, asymmetry was positively associated with the odds of contemporaneous breast cancer (P-for-linear-trend (Pt) = 0.018). This association was stronger for first (prevalent) screens (Pt = 0.012). Both DV and BV asymmetry were positively associated with the odds of an interval cancer diagnosis (Pt = 0.060 and 0.030, respectively). Neither BV nor DV asymmetry were associated with the odds of having a subsequent screen-detected cancer.

CONCLUSIONS

Increased DV asymmetry was associated with the risk of a breast cancer diagnosis at a contemporaneous screen or as an interval cancer. BV asymmetry was positively associated with the risk of an interval cancer diagnosis.

ADVANCES IN KNOWLEDGE

The findings suggest that DV and BV asymmetry may provide additional signals for detecting contemporaneous cancers and assessing the likelihood of interval cancers in population-based screening programmes.

Assessment and Classification of Mass Lesions Based on Expert Knowledge Using Mammographic Analysis

BACKGROUND

Masses are one of the most important indicators of breast cancer in mammograms, and their classification into two groups as benign and malignant is highly necessary. Computer Aided Diagnosis (CADx) helps radiologists enhance the accuracy of their decision. Hence, the system is required to support and assess with radiologist's interaction as an expert.

METHODS

In this research, classification of breast masses using mammography in the two main views which include MLO and CC, is evaluated with respect to the shape, texture and asymmetry aspect. Additionally, a method was developed and proposed using the classification of breast tissue density based on the decision tree.

DISCUSSION

This study therefore, aims to provide a method based on the human decision-making model that will help in designing the perfect tool for radiologists, regardless of the complexity of computing, costly procedures and also reducing the diagnosis error.

CONCLUSION

Results show that the proposed system for entirely fat, scattered fibroglandular densities, heterogeneously dense, and extremely dense breast achieved 100, 99, 99 and 98% true malignant rate, respectively with cross-validation procedure.

Ethnic and age differences in right-left breast asymmetry in a large population-based screening population

OBJECTIVE

Exposure to sex hormones is important in the pathogenesis of breast cancer and inability to tolerate such exposure may be reflected in increased asymmetrical growth of the breasts. This study aims to characterize, for the first time, asymmetry in breast volume (BV) and radiodense volume (DV) in a large ethnically diverse population.

METHODS

Automated measurements from digital raw mammographic images of 54,591 cancer-free participants (aged 47-73) in a UK breast screening programme were used to calculate absolute (cm³) and relative asymmetry in BV and DV. Logistic regression models were fitted to assess asymmetry associations with age and ethnicity.

RESULTS

BV and DV absolute asymmetry were positively correlated with the corresponding volumetric dimension (BV or DV). BV absolute asymmetry increased, whilst DV absolute asymmetry decreased, with increasing age (P-for-linear-trend <0.001 for both). Relative to Whites, Blacks had statistically significantly higher, and Chinese lower, BV and DV absolute asymmetries. However, after adjustment for the corresponding underlying volumetric dimension the age and ethnic differences were greatly attenuated. Median relative (fluctuating) BV and DV asymmetry were 2.34 and 3.28% respectively.

CONCLUSION

After adjusting for the relevant volumetric dimension (BV or DV), age and ethnic differences in absolute breast asymmetry were largely resolved.

ADVANCES IN KNOWLEDGE

Previous small studies have reported breast asymmetry-breast cancer associations. Automated measurements of asymmetry allow the conduct of large-scale studies to further investigate these associations.

Correlation-Based Ensemble Feature Selection Using Bioinspired Algorithms and Classification Using Backpropagation Neural Network

A framework for clinical diagnosis which uses bioinspired algorithms for feature selection and gradient descendant backpropagation neural network for classification has been designed and implemented. The clinical data are subjected to data preprocessing, feature selection, and classification. Hot deck imputation has been used for handling missing values and min-max normalization is used for data transformation. Wrapper approach that employs bioinspired algorithms, namely, Differential Evolution, Lion Optimization, and Glowworm Swarm Optimization with accuracy of AdaBoostSVM classifier as fitness function has been used for feature selection. Each bioinspired algorithm selects a subset of features yielding three feature subsets. Correlation-based ensemble feature selection is performed to select the optimal features from the three feature subsets. The optimal features selected through correlation-based ensemble feature selection are used to train a gradient descendant backpropagation neural network. Ten-fold cross-validation technique has been used to train and test the performance of the classifier. Hepatitis dataset and Wisconsin Diagnostic Breast Cancer (WDBC) dataset from University of California Irvine (UCI) Machine Learning repository have been used to evaluate the classification accuracy. An accuracy of 98.47% is obtained for Wisconsin Diagnostic Breast Cancer dataset, and 95.51% is obtained for Hepatitis dataset. The proposed framework can be tailored to develop clinical decision-making systems for any health disorders to assist physicians in clinical diagnosis.

Natural Breast Symmetry in Preoperative Breast Cancer Patients

Plastic surgeons aim to achieve breast symmetry during cosmetic and reconstructive breast surgery. They rely on measures of breast size, position, and projection to determine and achieve breast symmetry, but normative data on symmetry in preoperative breast reconstruction patients are scarce.

Poland Sequence: Retrospective Analysis of 66 Cases

INTRODUCTION AND OBJECTIVES

The literature reports many variations of Poland syndrome, which is a congenital disorder and a rare condition. The associated features are extremely variable, including alterations in the ipsilateral thorax and upper extremity and other malformations. This is used to designate the condition as Poland sequence (PS) because a sequence is a primary defect with a secondary cascade of structural changes. It is generally accepted that it is characterized as pathognomonic by absence/aplasia of the sternocostal aspect of the pectoralis major muscle of one side. Because it is considered a rare disease, and the incidence is low, we aimed to determine the features in all patients diagnosed at our institution to analyze the patterns and outcomes. We also revised the diagnosis according to the new classification proposed by Romanini et al to facilitate future treatments as well as to propose an improvement in the assessment and initial behavior when PS is suspected.

METHODS

We performed a retrospective study using our database from 1988. We identified 66 patients with a clinical diagnosis of PS in the Pediatric Plastic Surgery Unit of Hospital Sant Joan de Deu, Barcelona. We analyzed the medical charts, records, photographs, and imaging information to gather all the epidemiological information and clinical history, as well as the treatments received to analyze our experience with these patients. We used the TBN classification of Romanini et al, adding an S if there was upper extremity involvement (TBNS).We also conducted a systematic review consulting the following databases: PubMed, Cochrane Plus, Scopus, Web of Science, and Europe PMC.

RESULTS

Among the 66 patients, 27 were men, and 39 were women. The right side was affected in 51 patients (77.3%) (19 men and 32 women). In a total of 37 patients (56.1%; 16 men and 21 women), there was no upper extremity involvement. We found 40 cases with other associations, with scoliosis being the most common. Before 2007, the team performed surgery in 1 male patient and 4 female patients; after 2007, the actual team has performed reconstruction in 8 male patients and 16 female patients. In the female patients, the average volume of breast implants was 252.5 cc, and the average volume for fat grafting was 103.5 cc on the side affected with PS. There is a wide range of chest-breast clinical involvement, which was why we decided to readdress all the imaging and clinical history to classify the patients using a new classification system to learn how to optimally treat these cases in the future. In female patients, we used Romanini's TBN classification and added an S for upper extremity involvement; the T1B1N1S0 was the most frequently observed classification. Owing to the sample size and the disparity in sex distribution, we also reassessed publications in PubMed, Cochrane Plus, Scopus, Web of Science, and Europe PMC with more than 5 cases; we found that there were a total of 1600 patients with PS in the literature and that the distribution was almost 50% for men and women, including the patients in our study (611 women, 561 men).

CONCLUSIONS

We propose to include the presence of upper extremity involvement in Romanini's TBN classification (TBNS) for optimal management of these patients and use a standard number and profile for image documentation presurgery and postsurgery. We found that in the literature the ratio of men and women with PS was not 2 to 3:1, but 1:1. The most frequent phenotype of PS was T1B1N1S0 (hypoplasia or aplasia of the pectoralis muscles and soft tissue/breast hypoplasia/nipple-areolar complex with dislocation of <2 cm / absence of upper extremity involvement). There was no relationship between the side involved and patients' sex for the severity of the deformity and between the severity of the thoracic involvement and ipsilateral upper extremity association. In the literature, there are several plastic reconstruction methods available ranging from standard implants to microsurgery techniques. The selected procedure depends on the phenotype, patients' needs and expectations, availability of surgery in the hospital, and surgeons' criteria; thus, surgery has to be personalized while providing a match related to the risk/benefit, taking into account the degree of functional impairment. Since the author started her practice in the hospital in 2007, the timing for procedures has been proposed at the end of adolescence with 2 consecutive appointments without changes in the breast-thorax measures. The procedure performed has included implant use with lipofilling, yielding no major complications and a high rate of satisfaction during a maximum of 10 years of follow-up.

Applying a new maximum local asymmetry feature analysis method to improve near-term breast cancer risk prediction

Quantitative assessment of mammographic asymmetry has been investigated for breast cancer risk prediction. A new asymmetry feature extraction method was proposed in this study to enhance the risk prediction accuracy of near-term breast cancer. Breast areas in each pair of bilateral mammographic images were divided into several pairs of matched local annular regions and the maximum local asymmetry features (MLAF) were extracted from these regions. Radial basis function network (RBFN) was used to merge these features for breast cancer risk prediction. The dataset included 560 negative subjects. The risk prediction performance was tested using a leave-one-case-out (LOCO) cross-validation method. Area under the receiver operating characteristic curve (AUC) was used as the risk prediction performance evaluation index. AUC  =  0.898  ±  0.013 was obtained by using the MLAFs extracted from the annular regions, which was significantly higher than the AUC value of 0.505  ±  0.025 achieved by using global asymmetry features computed from the whole breast regions (p  <  0.05, DeLong's test) and much higher than the AUC values of 0.825  ±  0.017 and 0.717  ±  0.021 achieved by using MLAFs extracted from horizontal strip regions and vertical strip regions. The study demonstrated that near-term breast cancer risk prediction could be improved by using the proposed feature extraction method.

Estimating B1+ in the breast at 7 T using a generic template

Dynamic contrast-enhanced MRI is the workhorse of breast MRI, where the diagnosis of lesions is largely based on the enhancement curve shape. However, this curve shape is biased by RF transmit (B₁⁺ ) field inhomogeneities. B₁⁺ field information is required in order to correct these. The use of a generic, coil-specific B₁⁺ template is proposed and tested. Finite-difference time-domain simulations for B₁⁺ were performed for healthy female volunteers with a wide range of breast anatomies. A generic B₁⁺ template was constructed by averaging simulations based on four volunteers. Three-dimensional B₁⁺ maps were acquired in 15 other volunteers. Root mean square error (RMSE) metrics were calculated between individual simulations and the template, and between individual measurements and the template. The agreement between the proposed template approach and a B₁⁺ mapping method was compared against the agreement between acquisition and reacquisition using the same mapping protocol. RMSE values (% of nominal flip angle) comparing individual simulations with the template were in the range 2.00-4.01%, with mean 2.68%. RMSE values comparing individual measurements with the template were in the range8.1-16%, with mean 11.7%. The agreement between the proposed template approach and a B₁⁺ mapping method was only slightly worse than the agreement between two consecutive acquisitions using the same mapping protocol in one volunteer: the range of agreement increased from ±16% of the nominal angle for repeated measurement to ±22% for the B₁⁺ template. With local RF transmit coils, intersubject differences in B₁⁺ fields of the breast are comparable to the accuracy of B₁⁺ mapping methods, even at 7 T. Consequently, a single generic B₁⁺ template suits subjects over a wide range of breast anatomies, eliminating the need for a time-consuming B₁⁺ mapping protocol.

Non-randomness of the anatomical distribution of tumors

Background

Why does a tumor start where it does within an organ? Location is traditionally viewed as a random event, yet the statistics of the location of tumors argues against this being a random occurrence. There are numerous examples including that of breast cancer. More than half of invasive breast cancer tumors start in the upper outer quadrant of the breast near the armpit, even though it is estimated that only 35 to 40% of breast tissue is in this quadrant. This suggests that there is an unknown microenvironmental factor that significantly increases the risk of cancer in a spatial manner and that is not solely due to genes or toxins. We hypothesize that tumors are more prone to form in healthy tissue at microvascular ‘hot spots’ where there is a high local concentration of microvessels providing an increased blood flow that ensures an ample supply of oxygen, nutrients, and receptors for growth factors that promote the generation of new blood vessels.

Results

To show the plausibility of our hypothesis, we calculated the fractional probability that there is at least one microvascular hot spot in each region of the breast assuming a Poisson distribution of microvessels in two-dimensional cross sections of breast tissue. We modulated the microvessel density in various regions of the breast according to the total hemoglobin concentration measured by near infrared diffuse optical spectroscopy in different regions of the breast. Defining a hot spot to be a circle of radius 200 μm with at least 5 microvessels, and using a previously measured mean microvessel density of 1 microvessel/mm², we find good agreement of the fractional probability of at least one hot spot in different regions of the breast with the observed invasive tumor occurrence. However, there is no reason to believe that the microvascular distribution obeys a Poisson distribution.

Conclusions

The spatial location of a tumor in an organ is not entirely random, indicating an unknown risk factor. Much work needs to be done to understand why a tumor occurs where it does.

Electronic supplementary material

The online version of this article (10.1186/s41236-017-0006-7) contains supplementary material, which is available to authorized users.

Left-right analysis of mammary gland development in retinoid X receptor-α+/- mice

Left-right (L-R) differences in mammographic parenchymal patterns are an early predictor of breast cancer risk; however, the basis for this asymmetry is unknown. Here, we use retinoid X receptor alpha heterozygous null (RXRα^+/-) mice to propose a developmental origin: perturbation of coordinated anterior-posterior (A-P) and L-R axial body patterning. We hypothesized that by analogy to somitogenesis-in which retinoic acid (RA) attenuation causes anterior somite pairs to develop L-R asynchronously-that RA pathway perturbation would likewise result in asymmetric mammary development. To test this, mammary glands of RXRα^+/- mice were quantitatively assessed to compare left- versus right-side ductal epithelial networks. Unlike wild-type controls, half of the RXRα^+/- thoracic mammary gland (TMG) pairs exhibited significant L-R asymmetry, with left-side reduction in network size. In RXRα^+/- TMGs in which symmetry was maintained, networks had bilaterally increased size, with left networks showing greater variability in area and pattern. Reminiscent of posterior somites, whose bilateral symmetry is refractory to RA attenuation, inguinal mammary glands (IMGs) also had bilaterally increased network size, but no loss of symmetry. Together, these results demonstrate that mammary glands exhibit differential A-P sensitivity to RXRα heterozygosity, with ductal network symmetry markedly compromised in anterior but not posterior glands. As TMGs more closely model human breast development than IMGs, these findings raise the possibility that for some women, breast cancer risk may initiate with subtle axial patterning defects that result in L-R asymmetric growth and pattern of the mammary ductal epithelium.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.

Applying a new bilateral mammographic density segmentation method to improve accuracy of breast cancer risk prediction

PURPOSE

How to optimally detect bilateral mammographic asymmetry and improve risk prediction accuracy remains a difficult and unsolved issue. Our aim was to find an effective mammographic density segmentation method to improve accuracy of breast cancer risk prediction.

METHODS

A dataset including 168 negative mammography screening cases was used. We applied a mutual threshold to bilateral mammograms of left and right breasts to segment the dense breast regions. The mutual threshold was determined by the median grayscale value of all pixels in both left and right breast regions. For each case, we then computed three types of image features representing asymmetry, mean and the maximum of the image features, respectively. A two-stage classification scheme was developed to fuse the three types of features. The risk prediction performance was tested using a leave-one-case-out cross-validation method.

RESULTS

By using the new density segmentation method, the computed area under the receiver operating characteristic curve was 0.830 ± 0.033 and overall prediction accuracy was 81.0%, significantly higher than those of 0.633 ± 0.043 and 57.1% achieved by using the previous density segmentation method ([Formula: see text], t-test).

CONCLUSIONS

A new mammographic density segmentation method based on a bilateral mutual threshold can be used to more effectively detect bilateral mammographic density asymmetry and help significantly improve accuracy of near-term breast cancer risk prediction.

Mammographic parenchymal patterns and breast cancer risk in New South Wales North Coast Aboriginal and Torres Strait Islander women

INTRODUCTION

The objective of the study was to document the distribution of mammographic parenchymal patterns (MPP) of Indigenous Australian women attending BreastScreen New South Wales (NSW) North Coast, to profile breast cancer risk as it relates to breast density and to explore the correlation between MPP, breast size as described by the posterior nipple line (PNL) and age.

METHODS

Ethics was granted from CQUniversity Human Research Ethics Committee, NSW Population Health Services Research Ethics Committee and the Aboriginal Health and Medical Research Council Ethics Committee. A quantitative retrospective analysis reviewed 502 screening mammograms against the Tabár I-V MPP classification system. The PNL was measured in millimetres (mm) and the age of the patient documented.

RESULTS

A statistically significant variation in the distribution of MPP (P < 0.0001) was demonstrated, with patterns of I (23.9%), II (45.6%), III (10.4%), IV (15.9%) and V (4.2%). Statistically significant differences were noted in the age of subjects between patterns (P = 0.0002). Patterns I and V demonstrated statistically significant lower ages than II, III and IV (all P < 0.05). Pattern V demonstrated a statistically significant lower age than pattern I (P = 0.0393). Pattern V demonstrated a statistically significant lower PNL value than all other patterns (all P < 0.001/P < 0.0002); pattern II was statistically significantly higher in PNL value than all other patterns (P < 0.002/P < 0.001). No significant relationship was noted between PNL and age.

CONCLUSION

The study demonstrated that no identifiable or unique distribution of MPP was noted in this snapshot of Indigenous women. A larger study of Indigenous Australian women is required for validation.

Breast Volume Asymmetry Value, Ratio, and Cancer Risk

AIM

The aim of this study was to investigate the criteria for determining the cancer risk of the breast asymmetry by comparing breast volume asymmetry levels between healthy women and women with cancer.

MATERIALS AND METHODS

Two hundred and one women with breast cancer (group 1) were compared with 446 healthy women (group 2) who had no pathologic findings in breast sonography and mammograpy repeated with one-year interval. Data were evaluated retrospectively. Each breast volume was measured twice by Grossman-Roudner Discs. The mean value has been recorded. The amounts of volume difference between two breasts (asymmetry value) and the rates of the volume difference to the breast volume of the smaller side (asymmetry ratio) were compared in both groups.

RESULTS

There was a statistically significant difference between two groups with regard to average age and body mass index (P < 0.01). This significance was decreased but not disappeared, when the comparison was made within the 40-69 age group (P > 0.01). The rate of cases with asymmetry value over 50 mL was significantly higher in the cancer group (P = 0.029). Unfortunately, it disappeared in the 40-69 age group (P = 0.201). The breast volume asymmetry ratio over 20% was significantly higher in the cancer group both in all ages and in the 40-69 age group (P < 0.01). Odds ratio was 2.18 in the entire (all) series and 2.01 in the 40-69 age group. Moreover, there was no significant difference with regard to the rate of tumor location between the smaller or larger side of breast.

CONCLUSION

Our data show that there is a positive correlation between breast asymmetry ratio over 20% and breast cancer risk. These results need to be confirmed by prospective randomized controlled trials.

A new approach to develop computer-aided detection schemes of digital mammograms

The purpose of this study is to develop a new global mammographic image feature analysis based computer-aided detection (CAD) scheme and evaluate its performance in detecting positive screening mammography examinations. A dataset that includes images acquired from 1896 full-field digital mammography (FFDM) screening examinations was used in this study. Among them, 812 cases were positive for cancer and 1084 were negative or benign. After segmenting the breast area, a computerized scheme was applied to compute 92 global mammographic tissue density based features on each of four mammograms of the craniocaudal (CC) and mediolateral oblique (MLO) views. After adding three existing popular risk factors (woman's age, subjectively rated mammographic density, and family breast cancer history) into the initial feature pool, we applied a sequential forward floating selection feature selection algorithm to select relevant features from the bilateral CC and MLO view images separately. The selected CC and MLO view image features were used to train two artificial neural networks (ANNs). The results were then fused by a third ANN to build a two-stage classifier to predict the likelihood of the FFDM screening examination being positive. CAD performance was tested using a ten-fold cross-validation method. The computed area under the receiver operating characteristic curve was AUC = 0.779   ±   0.025 and the odds ratio monotonically increased from 1 to 31.55 as CAD-generated detection scores increased. The study demonstrated that this new global image feature based CAD scheme had a relatively higher discriminatory power to cue the FFDM examinations with high risk of being positive, which may provide a new CAD-cueing method to assist radiologists in reading and interpreting screening mammograms.

Breast size and breast cancer: a systematic review

BACKGROUND

There are many known breast cancer risk factors, but traditionally the list has not included breast size. The aim of this study was to synthesize the literature on breast size as a risk factor for breast carcinoma by examining studies addressing this question both directly and indirectly.

METHODS

A systematic review was performed searching MEDLINE from 1950 to November 2010, and updated again in February 2014. Literature was sought to assess the relationship between the following variables and breast cancer: 1) breast size; 2) breast reduction; 3) breast augmentation; and 4) prophylactic subcutaneous mastectomy. Findings were summarized and the levels of evidence were assessed.

RESULTS

50 papers were included in the systematic review. Increasing breast size appears to be a risk factor for breast cancer, but studies are limited by their retrospective nature, imperfect size measurement techniques and confounding variables. The evidence is stronger for risk reduction with breast reduction, including prophylactic subcutaneous mastectomy at the extreme. Generally the breast augmentation population has a lower risk of breast cancer than the general population, but it is unclear whether or not this is related to the bias of small breasts in this patient population and the presence of other confounders.

CONCLUSIONS

There is direct and indirect evidence that breast size is an important factor in the risk of developing breast cancer. Plastic surgeons are in a unique position to observe this effect. Well-designed prospective studies are required to further assess this risk factor.

Association between computed tissue density asymmetry in bilateral mammograms and near-term breast cancer risk

This study investigated association between bilateral mammographic density asymmetry and near-term breast cancer risk. A data base of digital mammograms acquired from 690 women was retrospectively collected. All images were originally interpreted as negative by radiologists. During the next subsequent screening examinations (between 12 and 36 months later), 230 women were diagnosed positive for cancer, 230 were recalled for additional diagnostic workups and proved to be benign, and 230 remained negative (not recalled). We applied a computerized scheme to compute the differences of five image features between the left and right mammograms, and trained an artificial neural network (ANN) to compute a bilateral mammographic density asymmetry score. Odds ratios (ORs) were used to assess associations between the ANN-generated scores and risk of women having detectable cancers during the next screening examinations. A logistic regression method was applied to test for trend as a function of the increase in ANN-generated scores. The results were also compared with ORs computed using other existing cancer risk factors. The ORs showed an increasing risk trend with the increase in ANN-generated scores (from 1.00 to 9.07 between positive and negative case groups). The regression analysis also showed a significant increase trend in slope (p < 0.05). No significant increase trends of the ORs were found when using woman's age, subjectively rated breast density, or family history of breast cancer. This study demonstrated that the computed bilateral mammographic density asymmetry had potential to be used as a new risk factor to improve discriminatory power in predicting near-term risk of women developing breast cancer.

Prediction of near-term breast cancer risk based on bilateral mammographic feature asymmetry

RATIONALE AND OBJECTIVES

The objective of this study is to investigate the feasibility of predicting near-term risk of breast cancer development in women after a negative mammography screening examination. It is based on a statistical learning model that combines computerized image features related to bilateral mammographic tissue asymmetry and other clinical factors.

MATERIALS AND METHODS

A database of negative digital mammograms acquired from 994 women was retrospectively collected. In the next sequential screening examination (12 to 36 months later), 283 women were diagnosed positive for cancer, 349 were recalled for additional diagnostic workups and later proved to be benign, and 362 remain negative (not recalled). From an initial pool of 183 features, we applied a Sequential Forward Floating Selection feature selection method to search for effective features. Using 10 selected features, we developed and trained a support vector machine classification model to compute a cancer risk or probability score for each case. The area under the receiver operating characteristic curve and odds ratios (ORs) were used as the two performance assessment indices.

RESULTS

The area under the receiver operating characteristic curve = 0.725 ± 0.018 was obtained for positive and negative/benign case classification. The ORs showed an increasing risk trend with increasing model-generated risk scores (from 1.00 to 12.34, between positive and negative/benign case groups). Regression analysis of ORs also indicated a significant increase trend in slope (P = .006).

CONCLUSIONS

This study demonstrates that the risk scores computed by a new support vector machine model involving bilateral mammographic feature asymmetry have potential to assist the prediction of near-term risk of women for developing breast cancer.

Evaluating the Relationship between Body Size and Body Shape with the Risk of Breast Cancer

OBJECTIVE

This study aims to determine the relationship between body size and body shape with the risk of breast cancer.

METHODS

In this case control study, 480 women participated (240 women with breast cancer in case group and 240 healthy women in control group). After completing the interview form, the weight, height, waist circumference, hip circumference and breast size, were measured. The data were analyzed using statistical test by SPSS11.5.

RESULTS

The present study showed that the mean of hip circumference were significantly different in both groups (p=0.036). The size of the breast was statistically significant between the two groups. Thyroid type, one of the body shapes, was more seen in the case group than control group (p<0.001).

CONCLUSION

This study revealed that the risk of breast cancer increases with increased hip circumference. In addition, the results indicate that body shape may be a useful predictor in determining the risk of breast cancer. More studies should be designed to address this subject.

Prenatal DES exposure in relation to breast size

PURPOSE

Prenatal DES exposure has been associated with increased risk of breast cancer, but the mechanisms are unknown. Larger bra cup size has also been associated with increased breast cancer risk, although not consistently. We investigated the relation of prenatal DES exposure to mammary gland mass, as estimated by bra cup size.

METHODS

In 2006, 3,222 DES-exposed and 1,463 unexposed women reported their bra cup size, band size (chest circumference), and weight at age 20. Prevalence ratios (PR) were calculated for DES exposure in relation to large bra cup size, with control for year of birth and study cohort. Primary analyses were carried out among women who reported a chest circumference of no more than 32 inches because their cup size would be less influenced by fat mass.

RESULTS

Within this group, DES-exposed women had an estimated 45% increased prevalence (95% CI 0.97-2.18) of large cup size (C or greater) relative to unexposed women. The PR was further increased among women in this group who had a body mass index of < 21 at age 20: PR = 1.83 (95% CI 1.11-3.00). The PR for high-dose DES exposure relative to no exposure was 1.67, 95% CI 1.02-2.73, whereas there was no association of bra cup size with low-dose exposure.

CONCLUSIONS

These results provide support for the hypothesis that in utero DES exposure may result in greater mammary gland mass. Taken together with previous research on bra size and breast cancer risk, these findings suggest a mechanism for a possible association of in utero DES exposure with increased risk of breast cancer.

Bilateral mammographic density asymmetry and breast cancer risk: a preliminary assessment

To improve efficacy of breast cancer screening and prevention programs, it requires a risk assessment model with high discriminatory power. This study aimed to assess classification performance of using computed bilateral mammographic density asymmetry to predict risk of individual women developing breast cancer in near-term. The database includes 451 cases with multiple screening mammography examinations. The first (baseline) examinations of all case were interpreted negative. In the next sequential examinations, 187 cases developed cancer or surgically excised high-risk lesions, 155 remained negative (not-recalled), and 109 were recalled benign cases. From each of two bilateral cranio-caudal view images acquired from the baseline examination, we computed two features of average pixel value and local pixel value fluctuation. We then computed mean and difference of each feature computed from two images. When applying the computed features and other two risk factors (woman's age and subjectively rated mammographic density) to predict risk of cancer development, areas under receiver operating characteristic curves (AUC) were computed to evaluate the discriminatory/classification performance. The AUCs are 0.633±0.030, 0.535±0.036, 0.567±0.031, and 0.719±0.027 when using woman's age, subjectively rated, computed mean and asymmetry of mammographic density, to classify between two groups of cancer-verified and negative cases, respectively. When using an equal-weighted fusion method to combine woman's age and computed density asymmetry, AUC increased to 0.761±0.025 (p<0.05). The study demonstrated that bilateral mammographic density asymmetry could be a significantly stronger risk factor associated to the risk of women developing breast cancer in near-term than woman's age and assessed mean mammographic density.

Computerized prediction of risk for developing breast cancer based on bilateral mammographic breast tissue asymmetry

This study developed and assessed a computerized scheme to detect breast abnormalities and predict the risk of developing cancer based on bilateral mammographic tissue asymmetry. A digital mammography database of 100 randomly selected negative cases and 100 positive cases for having high-risk of developing breast cancer was established. Each case includes four images of cranio-caudal (CC) and medio-lateral oblique (MLO) views of the left and right breast. To detect bilateral mammographic tissue asymmetry, a pool of 20 computed features was assembled. A genetic algorithm was applied to select optimal features and build an artificial neural network based classifier to predict the likelihood of a test case being positive. The leave-one-case-out validation method was used to evaluate the classifier performance. Several approaches were investigated to improve the classification performance including extracting asymmetrical tissue features from either selected regions of interests or the entire segmented breast area depicted on bilateral images in one view, and the fusion of classification results from two views. The results showed that (1) using the features computed from the entire breast area, the classifier yielded the higher performance than using ROIs, and (2) using a weighted average fusion method, the classifier achieved the highest performance with the area under ROC curve of 0.781±0.023. At 90% specificity, the scheme detected 58.3% of high-risk cases in which cancers developed and verified 6-18 months later. The study demonstrated the feasibility of applying a computerized scheme to detect cases with high risk of developing breast cancer based on computer-detected bilateral mammographic tissue asymmetry.

Lymphatic drainage and tumour prevalence in the breast: a statistical analysis of symmetry, gender and node field independence

Current understanding of the lymphatics draining the breast is controversial, despite its known importance in the spread of breast cancer. Similarly, knowledge regarding the spatial distribution of primary tumours in the breast is limited. This study sought to test commonly held assumptions in this field, including: (i) that breast lymphatic drainage and tumour prevalence are symmetric between the left and right sides of the body, (ii) that males and females have the same drainage patterns and tumour prevalences, and (iii) that lymphatic drainage in the breast occurs independently to different node fields. This study has used lymphoscintigraphy data from 2304 breast cancer patients treated at the RPAH Medical Centre, Sydney, Australia. Symmetry of lymphatic drainage and tumour distribution as well as gender differences were tested using Fisher's exact test. Drainage independence was assessed using Fisher's exact test, and a multivariate probit model was used to test for drainage correlations. Results showed that the breasts are likely to have symmetric lymphatic drainage and tumour prevalence, and that there is no significant difference between males and females. Furthermore, results showed that direct lymphatic drainage of the breasts is likely to be independent between node fields. Collectively, these results serve to further our understanding of lymphatic anatomy and the distribution of tumours in the breast.

Signals of Genetic Quality and Maternal Investment Capacity: The Dynamic Effects of Fluctuating Asymmetry and Waist-to-Hip Ratio on Men’s Ratings of Women’s Attractiveness

Fluctuating asymmetry (FA) and waist-to-hip ratio (WHR) are frequently studied physical attractiveness variables in social and evolutionary psychology. FA represents deviations in bilateral symmetry—differences between left and right body parts. WHR is the ratio of the smallest part of the waist to the largest part of the hips. Although FA and WHR are important mate preference criteria, research has not examined their joint influence on attraction. Thus, 140 heterosexual male undergraduates ranked—and 118 rated—the attractiveness of 10 photographs of rear-facing nude women. Women’s FA and WHR were negatively related to attractiveness separately, after controlling for each other and after controlling for body mass index (BMI). An FA × WHR interaction emerged, such that men’s preferences for lower WHRs increased as FA decreased, even after controlling for BMI. FA and WHR affected attractiveness in ways consistent with the information they carry and its likely effects on offspring quality.

Women with large breasts are at an increased risk of advanced breast cancer

Background

The risk of nodal metastasis is higher in women with bigger breast. It is not clear if this increase is due to the size of the breast (largely related to obesity) or is the result of larger tumour size at presentation (due to delayed diagnosis). It is hypothesised that women with large breasts are more likely to have node positive disease mainly attributable to their breast size.

Patients and methods

One hundred and twenty consecutive patients who underwent mastectomy during the year 2004 and 2005 for primary breast cancers in a large Teaching Hospital were included in the study. Patient's variable and tumour variable were collected and analysed by SPSS^® computer programme.

Results

It was found that big breasted women (those patients with mastectomy weight greater than 800 g) had a significantly greater tumour size than those with smaller breasts (p = 0.019, Mann-Whitney test) but there was no significant difference in grade (Kendall's tau-b = 0.055, p = 0.57) or lymph node positivity (Kendall's tau-b = 0.011, p = 0.93) between the two groups. Although, the tumour size was significantly greater in those with lymph node metastases (p < 0.001) but mastectomy weight was not found to be significantly greater in those with lymph node metastases (p = 0.11). For patients with similar tumour sizes mastectomy weight was not significantly greater in those patients with lymph node metastases (p = 0.28).

Conclusion

It is concluded that increased incidence of lymph node positivity at presentation big-breasted women is because of larger size of the primary tumour and not due to the size of the breast alone.

Breast asymmetry and predisposition to breast cancer

INTRODUCTION

It has been shown in our previous work that breast asymmetry is related to several of the known risk factors for breast cancer, and that patients with diagnosed breast cancer have more breast volume asymmetry, as measured from mammograms, than age-matched healthy women.

METHODS

In the present study, we compared the breast asymmetry of women who were free of breast disease at time of mammography, but who had subsequently developed breast cancer, with that of age-matched healthy controls who had remained disease-free to time of the present study. The study group consisted of 252 asymptomatic women who had normal mammography, but went on to develop breast cancer. The control group were 252 age-matched healthy controls whose mammograms were also normal and who remained free of cancer during the study period. Breast volume was calculated from the cranio-caudal mammograms for each group, and the relationships between asymmetry, established risk factors and the presence or absence of breast cancer were explored.

RESULTS

The group who went on to develop breast cancer had higher breast asymmetry than controls (absolute asymmetry odds ratio 1.50 per 100 ml, confidence interval (CI) 1.10, 2.04; relative asymmetry 1.09, CI 1.01, 1.18), increased incidence of family history of breast cancer, lower age at menarche, later menopause, later first pregnancies and a higher frequency of high risk breast parenchyma types. Conditional logistic regression analysis showed that breast asymmetry, height, family history of breast cancer, age at menarche, parenchyma type and menopausal status were significant independent predictors of breast cancer. When age at menopause was included in the model for the subgroup of post-menopausal women, absolute breast fluctuating asymmetry (FA) and relative breast FA remained significant effects.

CONCLUSION

Breast asymmetry was greater in healthy women who later developed breast cancer than in women who did not.

A review of developmental instability, parasitism and disease

Developmental instability is reflected in imprecise development caused by perturbations of the developmental process, while developmental stability reflects the ability to avoid or reduce such perturbations by developmental means. Developmental instability has been hypothesized to reflect overall individual condition, and asymmetric or otherwise aberrant individuals have thus been predicted to be particularly severely affected by disease and parasitism. An extensive review of the literature on animals, including humans, revealed consistent relationships between increased bilateral asymmetry and elevated risk of parasitism. Parasitism, including parasitism of mothers, is a cause of asymmetry as shown by a number of experiments, and asymmetric individuals are differentially susceptible to a range of different parasites. Extensive studies of humans have shown that asymmetric individuals also suffer disproportionately from a range of different diseases including mental diseases. Studies of transgenic organisms have now demonstrated that single genes associated with disease is a sufficient cause of increased asymmetry. A number of studies have also shown that activation of the immune system causes increased asymmetry in developing individuals, and that asymmetry and immunity show negative covariation. These findings may have important implications for the study of susceptibility of hosts to infectious disease.

Physical attractiveness and health: comment on Weeden and Sabini (2005)

Evolutionary behavioral biology suggests that certain characteristics of the human face and body are important for mate preferences and are therefore subject to sexual selection. J. Weeden and J. Sabini identify a number of weaknesses in the association between traits' attractiveness and health. In contrast, the authors argue that (a) studies on preferences for physical characteristics that rely on 1 trait permit only limited interpretation, (b) limitations placed on J. Weeden and J. Sabini's review exclude important associations, (c) there are misconceptions in their treatment of some traits, and (d) their selected literature provides an inaccurate picture regarding effect size. The authors suggest that future research in this field should seek conceptual and methodological constancy in trait selection and in the evaluation of attractiveness- and health-related traits.

An Objective Evaluation of Breast Symmetry and Shape Differences Using 3-Dimensional Images

BACKGROUND

The concept of natural breast asymmetry is well known; however, actual documentation in the literature is limited. New technology is currently available which provides 3-dimensional surface images of the breast and the ability to qualitatively determine differences in breast size, shape, and contour. The purpose of this report is to objectively determine the extent to which this natural breast asymmetry exists.

METHODS

Eighty-seven women without a history of breast cancer or previous breast surgery were included. Images were obtained using 3dMD technology. Data points queried included age, parity, body mass index (BMI), ethnicity, and bra size. Left/right images were superimposed and the distance between the 2 surfaces, and contour was calculated. The degree of asymmetry was determined and comparisons were made. Similar differences in nipple-to-notch measurements were calculated and compared. Subjective evaluations were included for clinical relevance.

RESULTS

The average age was 49.6 years (range: 19-77), with an average BMI of 25 (range: 18.5-36.7). The average nipple to notch on the left was 24.3 cm and 23.8 cm on the right. The nipple-to-notch asymmetry was on average 3.2%, with the left breast measurement being greater the majority of the time (62%). The mean distance between each breast demonstrated consistent breast asymmetry, with an average measurement of +0.5 mm (left breast being larger than the right). The degree of breast asymmetry was documented by a root mean square value (RMS) of 5.93 mm. This was not related to age, parity, or ethnicity; however, it was significantly higher in those patients with larger BMI, cup size, and chest-wall circumference. Only 10% of women were found to have severe breast asymmetry on subjective evaluation, which correlated objectively with the RMS in that group being significantly higher at 9.8 mm (P < 0.05). There were no predictable patterns of asymmetry; however, the most common pattern was larger laterally and smaller medially, found in 32% of the women.

CONCLUSION

Natural breast asymmetry does exist, demonstrated objectively using 3-dimensional surfaces images. The left breast is on average larger than the right, with differences in size and shape being consistent but fairly unpredictable. It is important that we know baseline differences in breast symmetry prior to objectively analyzing results following esthetic and reconstructive breast surgery.

A prospective study of breast size and premenopausal breast cancer incidence

Studies of the association between breast size, as a proxy for mammary gland mass, and breast cancer risk have given equivocal results. Most have been case-control studies with limited statistical power. We conducted a prospective analysis of the relation between breast size as measured by self-reported bra cup size and breast cancer risk among premenopausal women enrolled in the Nurses' Health Study II. Bra cup size at age 20 was assessed among 89,268 premenopausal women aged 29-47 in 1993. Subsequent incident cases of invasive breast cancer were assessed until 2001. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated with a Cox proportional hazards model adjusting for potential confounders and risk factors for breast cancer. During 622,732 person-years of follow-up, 803 premenopausal women were newly diagnosed with invasive breast cancer. For women with a BMI below 25 kg/m2, those with a bra cup size of "D or larger" had a significantly higher incidence of breast cancer than women who reported "A or smaller" (covariate adjusted HR=1.80; 95% CI 1.13-2.88; ptrend=0.01). There was no significant association among women with a BMI of 25 kg/m2 or higher. Stratifying by BMI at age 18 at a cutoff point of 21 kg/m2 gave similar results. Larger bra cup size at a young age is associated with a higher incidence of premenopausal breast cancer, though this association is limited to leaner women.

The second to fourth digit ratio in elite and non-elite female athletes

Contests in the animal world to determine social status almost exclusively involve males, which points out that androgens may be indispensable in the development of competitive instincts. In animal studies, it has been shown that prenatal exposure to androgens may produce permanent changes toward more aggressive behavior in adulthood. Thus, there is a strong suspicion that women involved in competitive activities, such as sports, may have been exposed to high androgen levels in utero. There is strong evidence that the ratio between the second to fourth digits ratio (2D:4D ratio) correlates negatively with intrauterine androgen concentrations and could potentially be used as a marker for prenatal androgen exposure. Therefore, the purpose of our study was to test the hypothesis that women engaged in sports have lower 2D:4D ratio-a marker of high prenatal androgen exposure. We measured the 2D:4D ratios in elite and non-elite female athletes and compared them with female individuals not engaged in any sport activities. Our results showed that elite female athletes have significantly lower left hand 2D:4D ratios compared to the control group (P < 0.05). Therefore, we can speculate that low 2D:4D ratio may be a positive correlate of sports potential in females.

Physical Attractiveness and Health in Western Societies: A Review

Evidence from developed Western societies is reviewed for the claims that (a) physical attractiveness judgments are substantially based on body size and shape, symmetry, sex-typical hormonal markers, and other specific cues and (b) physical attractiveness and these cues substantially predict health. Among the cues that the authors review, only female waist-to-hip ratio and weight appear to predict both attractiveness and health in the claimed manner. Other posited cues--symmetry and sex-typical hormonal markers among them--failed to predict either attractiveness or health (or both) in either sex. The authors find that there is some indication that attractiveness has an overall relationship with health among women, but little indication that male attractiveness relates to male health.

Spatial variations in optical and physiological properties of healthy breast tissue

Near-infrared (NIR) diffuse optical spectroscopy (DOS) and diffuse optical imaging (DOI) show promise as noninvasive clinical techniques for breast cancer screening and diagnosis. Since NIR methods are based on optical contrast between healthy and diseased tissue, it is essential to characterize the sources of endogenous contrast in normal subjects. We report intra- and inter-subject variation and bilateral asymmetry of the optical and physiological parameters of 31 women using a seven-wavelength NIR frequency-domain photon migration (FDPM) instrument. Wavelength-dependent absorption and reduced scattering parameters (micro(a) and micro(s'), respectively) were measured in four major quadrants and the areolar regions of left and right breasts. These values were used to determine tissue concentrations of oxy-(HbO(2)) and deoxy-(Hb-R) hemoglobin, lipid content, water concentration, and tissue "scatter power." Mean total hemoglobin for premenopausal (PRE) women (20 to 30 microM) is approximately two-fold higher than for postmenopausal (POST) subjects at all positions. POST women have approximately 50% higher lipid content (50 to 60%) than PRE at all positions. Water concentration on average is 1.8-fold higher for PRE subjects (30 to 40%) than POST. These differences are most pronounced when comparing the areolar complex to the other regions of the breast. In premenopausal women, the areolar regions have 40 to 45% increased total hemoglobin concentration (THC), 20 to 25% lower lipid content, and 30 to 60% higher scatter power versus the quadrants. Small-scale (3 cm) changes in optical properties are negligible compared to large-scale variations over all quadrants, where the intrinsic spatial heterogeneity of healthy breast tissue is 20 to 40% for micro(a) and 5 to 12% for micro(s'). Although no consistent right-left differences are observed in the study population, relative differences between symmetric positions ranged from 18 to 30% for THC, 10 to 40% for adipose, 10 to 25% for water, and 4 to 9% for scattering (674 nm) within an individual.