Thursday, October 06, 2005

Mammography Screening

Mammography is the process of using low-dose X-rays (usually around 0.7 mSv) to examine the human breast. It is used to look for different types of tumors and cysts. Only mammography has been proven to reduce mortality from breast cancer. In some countries routine (annual to five-yearly) mammography of older women is encouraged as a screening method to diagnose early breast cancer.

Like all x-rays, mammograms use doses of ionizing radiation to create this image. Radiologists then analyze the image for any abnormal growths. Despite continuous improvements and innovations, mammography has garnered a sizable opposition in the medical community because of an error rate that is still high and the amount of harmful radiation used in the procedure. (Gofinan)

At this stage mammography is still the modality of choice for screening of early breast cancer. It is the gold-standard for other imaging methods such as ultrasound and NMR-tomography. CT has no real role in diagnosing breast cancer at the present. Ultrasound, Thermography, and Magnetic resonance are alternatives to mammography.

In a Swedish study of 60,000 women, 70 percent of the mammographically detected tumors weren't tumors at all. These "false positives" aren't just financial and emotional strains, they may also lead to many unnecessary and invasive biopsies. In fact, 70 to 80 percent of all positive mammograms do not, upon biopsy, show any presence of cancer.

At the same time, mammograms also have a high rate of missed tumors, or "false negatives." Dr. Samuel S. Epstein, in his book, The Politics Of Cancer, claims that in women ages 40 to 49, one in four instances of cancer is missed at each mammography. The National Cancer Institute (NCI) puts the false negative rate even higher at 40 percent among women ages 40-49. National Institutes of Health spokespeople also admit that mammograms miss 10 percent of malignant tumors in women over 50. Researchers have found that breast tissue is denser among younger women, making it difficult to detect tumors. For this reason, false negatives are twice as likely to occur in premenopausal mammograms.


Post a Comment

<< Home