In the United states, Cancer is responsible for 23% of all deaths annually with the rate declining at 1% between 1990 and 2000 (Mitchell, et al.
2006). The word “cancer” is derived from the Latin word meaning “crab” due to its spread usually seen in cancers that metastasize. Cancer is one of the life threatening diseases and contributes a significant cause of morbidity and mortality in the world at large.
Breast cancer can affect both male and female but is rarely seen in males due to local size of tissue and lesser application of the associated risk factors .Breast cancer is the most common cancer in women and the second most common cause of cancer death in women in the particularly in the United States only after lung cancer (Kriege, et al. 2004). Risk factors for breast cancer include being older than 45 years of age, nulliparity, early menarche, late menopause, positive history of breast cancer in first degree relatives, positive history of cancer in contralateral breast.
The pathogenesis of breast cancer is attributed to hyper oestrogenism and thus the use of oral contraceptive pills(progestins only) provide some protection against breast cancer as well as breast feeding..Symptoms of breast cancer include local pain of breast, palpable mass on breast, loss of weight, bloody or purulent discharge from nipple, skin ulceration. Some may however be silent until late in the course of disease. Detecting breast cancer has been a serious concern, as early detection as in most cancers reduce significantly the mortality rates, for example the advent of the Papanicolao “pap” smear” has reduced the incidence of cervical cancers. Much work has thus been done and is being done to catch breast cancers in their earliest detectable states.Today with the increased awareness of breast cancer risk, women over the age of 40 are undergoing mammography for screening, leading to detection of cancers in earlier stages and a consequential improvement in survival rates.
Even with high awareness breast cancer remains the most common cause of death in women between the ages of 45 and 55. In a breast cancer patient, cancer usually forms in the ducts and lobules (National Cancer Institute, 2007). Breast cancer has been linked to a number of genetic changes.It is estimated that about 50 percent of breast cancers associated with genetic risk factors are linked to a mutation of the BRCA1 or BRCA2 genes which repair damaged DNA.
This study also suggests that women who carry BRCA mutations and those with multiple relatives who developed breast or ovarian cancer at a young age face a decision about whether to have prophylactic surgery or undergo a lifetime of intensive screening (Center for the Advancement of Health, 2007).With the help of proper diagnosis of the stages it is possible to detect the extent to which a particular cancer has spread and this in turn helps the physicians to take decisions concerning treatment options. Breast cancer treatment depends upon several factors, including the type of cancer and the extent to which it has spread. In general treatment for breast cancer may involve surgery, radiation therapy, hormonal therapy, and/or chemotherapy.
When compared to the earlier decades studies have suggested that the advances in screening, diagnosis, and treatment has decreased the death rate for breast cancer by about 20% (Stoppler, 2007). Methods of Diagnosis of Breast Cancer The diagnosis of breast cancer involves a good history from the patient alongside a thorough physical examination with basic chemical and radiological investigations. Patients showing no symptoms are usually screened with X-ray mammography to look for tumors, cysts, calcifications or any obvious fibrocystic change.The Magnetic Resonance imaging “MRI” is a powerful imaging tool that makes use of magnetic field and pulses of radio wave energy to make images of organs and structures inside the body (Center for the Advancement of Health, 2007). Mammography is most often used for routine check up with other imaging techniques added if further investigation is necessary. Mammography involves compression of the breast between two metal plates and the use of a special type of camera to take pictures from two different angles or directly to a computer screen.
Computer-aided detection (CAD) is another technique that involves the use of computers to bring suspicious areas on a mammogram to the radiologist’s attention. It is used after the radiologist has done the initial evaluation of the mammogram. In the year 1998, the FDA approved a breast imaging device that uses CAD technology. (National Cancer Institute Fact Sheet, 2007). The breast cancer. org website reports that most often women find this breast compressions uncomfortable and painful for some, Ultrasound is also used to screen breast cancers.
It is also called sonography in which the imaging technique uses high-frequency sound waves that cannot be heard by human beings bounces off tissues and internal organs. As a result their echoes produce a picture called a sonogram. In general the ultrasound imaging of the breast is used to differentiate between solid tumors and fluid-filled cysts. This technique can also be used to evaluate lumps that are difficult to see on a mammogram. Ultrasound in come cases is used as part of other diagnostic procedures, such as fine needle aspiration.
In this procedure the tissue or fluid is removed with the help of a needle for examination called the biopsy. (National Cancer Institute Fact Sheet, 2007). In magnetic resonance imaging (MRI), a magnet linked to a computer creates detailed pictures of areas inside the body. The advantage with this technique is that it does not use radiation. Each MRI produces hundreds of images of the breast from different directions side-to-side, top-to-bottom, and front-to-back, which is then interpreted by a radiologist. MRI of breast is done in the following manner.
First the patient is asked to lie on her stomach on the scanning table. The breast hangs into a depression or hollow in the table, which contains coils that are able to detect the magnetic signal. The table is then moved into a tube-like machine that contains the magnet. If the patient is claustrophobic an open MRI or a mild sedative could be given.
Once an initial set of images are taken, the patient may be given a contrast agent intravenously. The contrast agent is not radioactive in nature and it is just used to improve the visibility of a tumor.After this additional images are then taken to view the tumor clearly. MRI basically works by aligning hydrogen protons in the magnetic field and then projecting 2D and 3D images on the screen in possible millimeter cuts. Advantages of MRI include the non-use of ionizing radiation and the ability to view in more than one plane ( In general, breast MRI is not used for routine breast cancer screening, but in recent years clinical trials are being performed to determine if MRI is helpful for screening certain women, such as young women at high risk for breast cancer.Besides it is found that MRI cannot always precisely distinguish between malignant cancer and benign (noncancerous) breast conditions. Additionally it also cannot detect microcalcifications like ultrasound.
(National Cancer Institute Fact Sheet, 2007). Researchers have found that MRI is used mainly to evaluate breast implants for leaks or ruptures, and also to assess abnormal areas detected by a mammogram or are felt after breast surgery or radiation therapy. However it can be used after breast cancer is diagnosed to measure the extent of the tumor in the breast.MRI is also sometimes useful in imaging dense breast tissue, which is often found in younger women, and in viewing other breast abnormalities that can be felt but are not visible with conventional mammography or ultrasound (National Cancer Institute, 2007). In general, breast MRI is not used for routine breast cancer screening, but in recent years clinical trials have been performed to determine if MRI is helpful for screening certain women, such as young women at high risk for breast cancer.It is found that MRI cannot always precisely distinguish between malignant cancer and benign (noncancerous) breast conditions. Additionally, it also cannot detect microcalcifications like ultrasound (National Cancer Institute Fact Sheet, 2007).
Researchers have found that MRI is used mainly to evaluate breast implants for leaks or ruptures, and also to assess abnormal areas detected by a mammogram or are felt after breast surgery or radiation therapy. However it can be used after breast cancer is diagnosed to measure the extent of the tumor in the breast.MRI is also sometimes useful in imaging dense breast tissue, which is often found in younger women, and in viewing other breast abnormalities that can be felt but are not visible with conventional mammography or ultrasound (National Cancer Institute, 2007). MRI provides multiple slices of high-resolution images of breast tissue, creating a three-dimensional picture (Optical Society of America, 2007).
Reasons for not using MRI for detection of breast cancer are many. For instance, because the mammograms are much less expensive than Magnetic Resonance Imaging (MRI), many prefer mammograms.Secondly, since MRI compress the breast to show all of the information in one view, they are a less effective tool, particularly when the breast is dense or in young woman.
Recently researchers at Dartmouth College and Dartmouth Medical School in 2006 combined two techniques, magnetic resonance imaging (MRI) and near-infrared optics, which they found to be potentially more precise method for diagnosing breast cancer. In this new technique, MRI is used to produce an image of the breast, providing adequate information on its structure, shape and composition.Additionally, the near-infrared light technique provides information on how the tissue is functioning, for instance, by finding out if a region contains a large amount of blood and is consuming oxygen rapidly then the patient may be suffering from cancer as early cancers typically consume oxygen. The researchers are hopeful that this dual-procedure of combining MRI with near-infrared light technique will be a key to learning which tissues are malignant even before performing a biopsy (Optical Society of America, 2007).The disadvantage with MRI is that it is extremely sensitive in detecting early cancer, but unfortunately because of its hypersensitivity it also picks up many breast changes that are not cancer, leading to a high incidence of negative biopsies and creating unnecessary stress on people. In other words, the false positive rate is high and may be unacceptable for low risk women (Anne Arundel Medical Center, 2004).
There are also studies that point out that MRI can detect cancers that may be missed in a routine mammogram.For instance, Kriege’s study (2007), published in the New England Journal of Medicine followed 969 women who had a recent diagnosis of breast cancer in one breast. They found that MRI was able to detect breast cancer in the second (contra lateral) breast of some of these women even when mammogram had been interpreted as negative. Specifically, 121 of these women had a suspicious or positive MRI, even though their mammogram showed negative results. Later when all of these MRI positive women had biopsies, 30 were found to be positive for cancer.Therefore, it can be said that MRI is useful when it comes to detecting early breast changes even when mammograms are not able to detect it. In case if the 30 women not had an MRI, the cancer in their other breast would not have been detected and their surgery and treatment might have been inadequate. Though these positive cases were detected it was found that even in very high-risk women who already had cancer the majority (91 of them) had false positives.
This shows that the false positive rate in a normal group of women may be even higher.The good news is that the women in the study who had a negative MRI were followed for another year and continued to have no cancer occurrence or reoccurrence in their second breast. In other words MRI had a negative predictive value of 99 percent (Young, 2007; Reichman, 2007). Studies conducted by Brem et al.
(2007) compared the sensitivity and specificity of breast-specific gamma imaging (BSGI) using a high-resolution breast-specific gamma camera and MRI in patients with indeterminate breast findings.They found that there was no statistically noteworthy disparity in sensitivity of cancer detection between BSGI and MRI. However, BSGI demonstrated a greater specificity than MRI, 71% and 25%, respectively.
Therefore this study suggested that BSGI has equal sensitivity and greater specificity than MRI for the detection of breast cancer (). Breast magnetic resonance imaging (MRI) has been proposed as an additional screening test for young women at high risk of breast cancer in whom mammography alone has poor sensitivity.A study conducted by Lord et al.
(2007) found that the effectiveness of MRI depend on assumptions about the benefits of early detection from trials of mammography screening in older average risk populations. He also stated that the extent to which high risk younger women receive the same benefits from early detection and treatment of MRI-detected cancers is yet to be established (). A study conducted by Drew et al. compared MRI with mammography, sonography, and physical examination in preoperative patients ().They found that the sensitivity for detecting multifocal breast cancer was 100% for MRI and 18% for standard modalities. A major criticism of MRI has been its lack of specificity, which varies in the literature from 31% to 91% (Flamm, 2005). MRI when it is compared mammography has a specificity of 93% to 99%.
Besides it was found that patients diagnosed positive with MRI had to conform it through a biopsy that added to the overall cost of treatment and is a burden. While MRI is effective in detecting breast cancer, its specificity for screening is much lower than that of mammography.The need for additional imaging ranged from 8% to 17% in MRI screening studies, and the biopsy rates ranged from 3% to 15% (Kriege, et al. 2004).
Studies have found that the rate of false-positive results is higher in women who undergo screening compared with a high-risk population. An American Cancer Society review found that the higher rate of biopsies and additional studies was acceptable in women with a high risk of breast cancer but inappropriate in low-risk women (Saslow, et al. , 2007).In conclusion, it can be said that MRI cannot be the used as an effective tool to detect breast cancer since there are several studies that support this fact. Besides, several negative cases being shown as positive cases of breast cancer that creates unnecessary anxiety in people. References Anne Arundel Medical Center, (2004) MRI helps find breast cancer in high-risk women more evidence point to MRI usefulness, Breast Health, September 2004. Retrieved November 4, 2007, from http://www. askaamc.
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