Screening women at high risk of breast cancer on the basis of evidence

Five-year analysis of magnetic resonance imaging as a screening tool in women at hereditary risk of breast cancer

INTRODUCTION

Women at very high risk of breast cancer are recommended to undertake enhanced surveillance with annual MRI in addition to mammography. We aimed to review the performance of breast MRI as a screening modality over its first 5 years at our institution.

METHODS

The study used a retrospective review using prospectively collected data from a consecutive series of women at high risk of developing breast cancer undergoing surveillance MRI.

RESULTS

Two hundred twenty-three women had at least one screening MRI. The median age was 42 years old. Sixty-nine (30.9%) were confirmed genetic mutation carriers. The remaining 154 (69.1%) women were classified as high risk based on family history, without a confirmed genetic mutation. Three hundred forty screening MRI studies were performed. Of these, 69 patients (20.3%) were recalled for further assessment. There was a significant reduction in the recall rate throughout the study for prevalent screens, from 50% (17/34) in 2008 to 14% (9/54) in 2011 (P = 0.004). The overall biopsy rate was 39 in 340 screens (11.5%). Four cancers were identified. Three were in confirmed BRCA1/BRCA2 mutation carriers, and one was found to be a carrier after the cancer was diagnosed. All four were identified as suspicious on MRI, with two having normal mammography. The cancer detection rate of MRI was 1.2% (4/340 screens). The overall positive predictive value was 7.0%, 6.7% for prevalent screens and 7.1% for subsequent screens.

CONCLUSIONS

Breast MRI as a screening modality for malignant lesions in women with high hereditary risk is valuable. The recall rate, especially in the prevalent round, improved with radiologist experience.

Risk of developing breast cancer by utilizing Gail model

The Gail model has been widely used to quantify an individual woman's risk of developing breast cancer by using important clinical parameters, usually for clinical counselling purposes or to determine eligibility for mammography and genetic tests. The aim of the present study was to estimate the five-year and lifetime breast cancer risk among women in Rasht, Iran. In this cross-sectional study, 314 women were evaluated at Alzahra Women Hospital in 2007. Participants were ≥35 years of age without a history of breast cancer. Risk estimation was performed using the computerized Gail model. A five-year risk >1.66% was considered high-risk; 5.1% of women were high-risk. The mean five-year breast cancer risk was 0.8% (SD±1). Mean breast cancer risk up to the age of 90 years (lifetime risk) was 9.0% (SD±3.9%); 16.2% of the participants had a five-year risk higher than the average woman of the same age, and 18.2% had the same risk. Also for the lifetime risk, 11.1% of the women had higher risk and 1.6% had the same risk as the average woman. Routine use of the Gail model is recommended for identifying women at high average risk for increasing the survival of women from breast cancer.

Silibinin-induced apoptosis in MCF7 and T47D human breast carcinoma cells involves caspase-8 activation and mitochondrial pathway

Silibinin, a natural flavonoid, under phase I/II clinical trial in prostate cancer patients was aimed to evaluate its chemotherapeutic potential in human breast cancer cell MCF7 and T47D. Results showed that T47D cells were found to be more sensitive to silibinin than MCF7 as observed by proliferation, clonogenic, and apoptotic assays, which was abrogated by pan-caspase inhibitor but remained unaffected by p53 inhibitor. Apoptotic events in both cell types differ temporally and also by magnitude that involved mitochondrial and caspase-8 activation pathway. These results have relevance in understanding silibinin treatment to breast tumor.

Estimating the cumulative risk of a false-positive under a regimen involving various types of cancer screening tests

OBJECTIVES

When evaluating screening for the early detection of cancer, it is important to estimate both harms and benefits. One common harm is a false-positive (FP), which is a positive screening result, perhaps followed by an invasive test, with no cancer detected on the diagnostic work-up or within a specified time period. An important goal is to estimate the risk of at least one FP, which we call the cumulative risk of an FP, if persons took a regimen of various screening tests, as is commonly recommended. The estimation is complicated because the data come from a study in which subjects are offered various screening tests in rounds with some missing tests in most subjects. Previous methods for estimating cumulative risk of FPs with a single type of test are not directly applicable, so a new approach was developed.

METHODS

The tests were ordered by appearance, where the last test was either the first FP (analogous to a failure time) or the last test taken with no FPs having occurred on that test or previously (analogous to a censoring time). We applied a Kaplan-Meier approach for survival analysis with the innovation that the hazard for a first FP for a given test depends on the type of test and number of previous tests of that type which were taken.

RESULTS

The method is illustrated with data from the screening arm of the randomized Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. With an FP defined as a diagnostic work-up in the absence of cancer (or advanced adenoma) within three years, the probability of at least one FP among 14 tests in men was 60.5% with 95% confidence interval of (59.3%, 61.6%).

CONCLUSION

A simple estimate is proposed for the probability of at least one FP if persons took a regimen of multiple screening tests of different types. The methodology is useful for summarizing the burden of multiphasic screening programmes.

The effect of an organized, nationwide breast cancer screening programme on non-organized mammography activities

OBJECTIVES

To analyse the effect of an organized, nationwide breast cancer screening programme on non-organized mammography activities in Hungary.

SETTING

The nationwide dataset of the Hungarian National Health Insurance Fund Administration covering the years 2000-2005.

METHODS

Data derived from the nationwide database of the Hungarian National Health Insurance Fund Administration. The study includes all women undergoing mammography before (2000-2001) and after (2002-2003/2004-2005) the introduction of organized screening.

RESULTS

The number of women having non-organized (opportunistic/diagnostic) mammograms was around 250,000 in 2000-2001, but increased to 350,000 in 2005. In the age group 45-64 years in 2000-2001, only 27.4% of all women undergoing mammography were examined within locally-organized programmes. After the introduction of the nationwide programme, this percentage increased to 61.0% in 2002-2003, and 56.3% in 2004-2005. After the introduction of the nationwide organized programme (2002-2003), the proportion of organized screening mammographies remained among the highest in county Hajdú-Bihar (78.4%) and Zala (88.3%) and increased significantly in county Vas (87.7%).

CONCLUSION

The introduction of an organized nationwide screening programme in Hungary resulted in increases in the number of screening mammographies, and also of non-organized mammographies. Although the ratio of organized screening versus non-organized mammography changed in favour of screening mammographies, there are large within-country differences between counties.

Early detection of cancer: ideas for a debate

Even if the overall number of cancer is increasing, the mortality has started to decrease in the Western World. The role of early detection in this decrease is a matter of debate. To assess its impact on mortality it is important to distinguish between diagnosis of cancer in symptomatic patients, and early detection in asymptomatic individuals who may self-refer or who may be offered ad hoc or systematic screening. The policies for early detection and screening vary greatly between European countries, despite many similarities in their cancer burden, and this partly reflects the uncertainties surrounding asymptomatic testing for cancer. A Task Force of European expert, held in Azzate (VA), Italy, established to address these issues, acknowledged the need for more research in the field of individual risk assessment since general statistics are more and more perceived as inadequate to design personal early detection plans. The group also recognised that combinations of early detection and screening will enforce the effectiveness of new treatments in curbing mortality curves, although policies will vary with different cancers.

Thermal Detection of Embedded Tumors Using Infrared Imaging

Breast cancer is the most common cancer among women. Thermography, also known as thermal or infrared imaging, is a procedure to determine if an abnormality is present in the breast tissue temperature distribution. This abnormality in temperature distribution might indicate the presence of an embedded tumor. Although thermography is currently used to indicate the presence of an abnormality, there are no standard procedures to interpret these and determine the location of an embedded tumor. This research is a first step towards this direction. It explores the relationship between the characteristics (location and power) of an embedded heat source and the resulting temperature distribution on the surface. Experiments were conducted using a resistance heater that was embedded in agar in order to simulate the heat produced by a tumor in the biological tissue. The resulting temperature distribution on the surface was imaged using an infrared camera. In order to estimate the location and heat generation rate of the source from these temperature distributions, a genetic algorithm was used as the estimation method. The genetic algorithm utilizes a finite difference scheme for the direct solution of the Pennes bioheat equation. It was determined that a genetic algorithm based approach is well suited for the estimation problem since both the depth and the heat generation rate of the heat source were accurately predicted.

Recent advances in diffuse optical imaging

We review the current state-of-the-art of diffuse optical imaging, which is an emerging technique for functional imaging of biological tissue. It involves generating images using measurements of visible or near-infrared light scattered across large (greater than several centimetres) thicknesses of tissue. We discuss recent advances in experimental methods and instrumentation, and examine new theoretical techniques applied to modelling and image reconstruction. We review recent work on in vivo applications including imaging the breast and brain, and examine future challenges.

Visualisation of calcifications and thin collagen strands in human breast tumour specimens by the diffraction-enhanced imaging technique: a comparison with conventional mammography and histology

Six excised human breast tissue specimens carrying benign and malignant tumours were examined with the diffraction-enhanced imaging technique. Diffraction-enhanced images were compared with diagnostic screen-film mammograms and the correlation with histological information of the specimens was established. The enhanced visibility of calcifications, some of which were smaller than 0.15 mm in diameter, is reported in detail. Fine details of the structures such as strands of collagen and contours between glandular and adipose tissue, which are barely visible at the contrast detection limit in the conventional absorption-based mammograms, are clearly visible in the diffraction-enhanced images. Microscopic study of the stained histopathological sections unequivocally confirms the correlation of the radiographic findings with the morphologic changes in specimens. An increased soft tissue contrast and a combination of information obtained with disparate diffraction-enhanced images provide better visibility of mammographically indistinguishable features. This kind of additional structural information of the breast tissue is required to improve assessment accuracy and earlier detection of the breast lesions. These advances in image quality make the method a very promising candidate for mammography.