Saving Women's Lives Strategies for Improving Breast Cancer Detection and Diagnosis (2005) / Chapter Skim
Currently Skimming:
Appendix A: Breast Cancer Technology Overview
Appendix A: Breast Cancer Technology Overview
Pages 279-309
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 279... ...
. And only 3 (screen-film mammography, digital mammography, and computer-aided detection [CAD]
|
From page 280... ...
Computer Uses computer Clinical use 1998 Aided algorithms to highlight for screening Detection suspicious areas on mammograms for the radiologist to review. Digital Similar to screen-film Clinical use 2000 Mammography mammography except for screening x-rays are recorded in digital format instead of on x-ray film.
|
From page 281... ...
The radiologist can see if any of the highlighted areas were missed on the initial review and require further evaluation. Initial studies show CAD technology may improve the accuracy of screening mammography by reducing the number of missed cancers.3,13 A 2004 study reported that the use of CAD was not associated with statistically significant changes in recall or breast cancer detection rates.15 However, all radiologists in that study were considered breast imaging specialists, and the results of this study should not be extrapolated to use by community radiologists who vary widely in their proficiency.11 The greatest clinical value of CAD probably does not lie in its ability to raise the performance level of all breast imagers, but rather in its potential to bring the performance level of general radiologists to that of breast imaging specialists.35
|
From page 282... ...
Despite the benefits of a digital medium, studies have not yet shown that digital mammography is more effective in finding cancer than conventional mammography. Digital mammography systems offer better contrast and lower spatial resolution at a lower radiation dose than traditional screen film mammography.20 However, the relative diagnostic accuracy of digital mammography as compared to traditional mammography has not yet been determined.
|
From page 283... ...
Currently, the most significant barrier to the adoption of the tomographic technology is the amount of time that it takes to reconstruct the image. Multiple images are necessary to reconstruct an adequate threedimensional image of the breast tissue.
|
From page 284... ...
performed by a physician that measures the resistance of breast tissue, providing a quantitative characterization of breast "lumps." Elastography Measures stiffness of Experimental use - breast tissue in response to a mechanical stimulus, developing a map of the mechanical properties of the tissue; thus, assisting the identification of abnormal tissue (e.g., hardened lesions)
|
From page 285... ...
Thermo- Uses several heat sensing Experimental use - rhythmometry probes to measure the (clinical prototype) surface temperature of the breast tissue over a 24-hour period to identify suspicious areas of the breast.
|
From page 286... ...
Elastography Mapping the mechanical properties (such as stiffness or elasticity) of breast tissue can identify abnormal tissue properties that are often associated with cancer growth.30 This method of cancer detection is known as elastography.
|
From page 287... ...
.b The increased vascular activity often results in an increase in surface temperatures of the breast near the location of tumor, which can be imaged through thermographic devices. In 1982, the FDA approved the first breast thermography device as an adjunctive breast cancer screening procedure.c Since then, several devices have been approved under the FDA's 510(k)
|
From page 288... ...
A small the United States amount of current is introduced into the body using a handheld probe; the breast tissue is then imaged using a technician held device. Microwave Microwave pulses are Experimental use -Imaging used to image the (clinical prototype)
|
From page 289... ...
. Electrical impedance is lower in cancerous breast tissue than normal breast tissue; therefore, electrical impedance scanning (EIS)
|
From page 290... ...
Two to three times the amount of electrical conductivity is observed through microwave imaging of cancerous breast tissue when contrasted with surrounding normal tissue.5,23,27,48 While researchers are still years away from clinical trials, they have studied the technique using breast phantoms (test objects that simulate the radiographic characteristics of normal and cancerous breast tissue) and excised breast samples.
|
From page 291... ...
Imaging the absorption of near-infrared light in breast tissue can quantify the hemoglobin content and volume of blood perfusing the tissue, providing contrast between the dense vasculature often associated with cancer and healthy tissue.21 Since most tumors require an abundance of nutrients delivered through the vasculature of the capillary bed for accelerated growth, the high oxygen content and blood volume has been demonstrated to correlate with malignancy.21,39 Furthermore, using a technique called diffuse optical tomography, three-dimensional visualizations can be constructed to
|
From page 292... ...
Lasers are used to illuminate the breast in 4-mm increments scanning the breast tissue from the chest wall to the nipple. Algorithms are then used to create threedimensional cross-sectional images of the breast.
|
From page 293... ...
The entire imaging session takes about one hour. Breast MRI is not FDA approved for routine breast cancer screening, but clinical trials are being performed to determine if MRI is valuable for
|
From page 294... ...
Uses of MRI may include assessment of abnormalities that are unclear on a mammogram, determination of the extent of tumor growth after initial diagnosis, and for evaluation of the effectiveness of treatments. MRI may also be useful in imaging augmented breast tissue, dense breast tissue (often found in younger women)
|
From page 295... ...
This accumulation of the tracer can then be imaged using a gamma camera to identify breast lesions. FDG-PET Radioactive compounds Clinical use for 1976*
|
From page 296... ...
is analyzed by computer algorithms to predict the behavior of the tissue. Genetic Testing This technique uses a blood Clinical use Not FDA test to identify genetic for risk regulated mutations that have been assessment associated with an increased risk of developing breast cancer.
|
From page 297... ...
Recently published evidence-based guidelines from the American Cancer Society concluded that there are currently insufficient data to recommend the use of ductal lavage either as an independent screening modality or in combination with screening mammography.47 Scintimammography Scintimammography involves injecting a radioactive tracer into the patient, which accumulates differently in cancerous and noncancerous tissues, to help physicians determine the presence of cancer. Currently, the technitium-99m sestamibi compound is the only radioactive tracer approved by the FDA for breast imaging.
|
From page 298... ...
For example, breast tissue with a high concentration of choline has been shown to be indicative of invasive breast cancers.54 Thus, by identifying alterations in the biochemistry of the tissue, i National Cancer Institute Fact Sheet. Improving Methods for Breast Cancer Detection and Diagnosis.
|
From page 299... ...
For example, tissue samples from an invasive cancer and from a benign cyst will have very different growth characteristics determined by the genetic makeup of the tissue and more importantly the expression of that genetic code (the relative level of gene activity)
|
From page 300... ...
Women who have BRCA mutations have a 36 to 85 percent lifetime chance of developing breast cancer while the general population has only a 13 percent chance.j In testing for these mutations, a small sample of blood is drawn, and the DNA is analyzed for genetic defects in the BRCA1 and BRCA2 genes. The test results can be either mutation-positive or mutation-negative (see Tables A-1 and A-2)
|
From page 301... ...
. Using computer algorithms, the relative levels of ionized proteins are measured and can be associated with the possible presence of a disease.
|
From page 302... ...
Core Needle Larger needle used to Clinical use Biopsy obtain tissue samples from a breast lesion. This procedure usually obtains enough tissue to allow a pathologist to make a definitive diagnosis.
|
From page 303... ...
Surgical Biopsy Traditional open surgical biopsy is the gold standard to which other methods of breast biopsies are compared.25 Surgical biopsy requires a 1.5to 2.0-inch incision in the breast to remove suspicious tissue for pathologi
|
From page 304... ...
The core needle biopsy procedure typically only takes a few minutes, and most patients are able to resume normal activity the same day. Core needle biopsy usually allows for a more accurate assessment of a breast mass than fine needle aspiration because the larger core needle usually removes enough tissue for the pathologist to evaluate abnormal cells in relation to the surrounding small sample of breast tissue taken with the specimen.45 Biopsy results are usually available within several days.
|
From page 305... ...
If the FNA diagnosis is positive, this procedure can result in an incomplete assessment because the cells cannot be evaluated in relation to the surrounding tissue, which is crucial to establishing the stage of cancer and prognosis. Yet, insufficient sample rates for nonpalpable lesions and lower relative diagnostic accuracy reduce the clinical utility of FNA.41 Larger samples from a more accurate core needle biopsy or open surgical biopsy may be needed to make a definitive diagnosis.
|
From page 306... ...
1984. Dielectric properties of normal & malignant human breast tissues at radiowave & microwave frequencies.
|
From page 307... ...
2002. Role of ultrasound-guided fine-needle aspiration of indetermi nate and suspicious axillary lymph nodes in the initial staging of breast carcinoma.
|
From page 308... ...
2001. Fine-needle aspiration biopsy of nonpalpable breast lesions in a multicenter clinical trial: results from the radiologic diagnostic oncology group V
|
From page 309... ...
2001. Human breast lesions: characterization with contrast-enhanced in vivo proton MR spectroscopy -- initial results.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.