Mammograms and Breast Exams

This month we’ll look at two recently published studies that involve detection of breast cancer.

In one study Janet Kay Bobo, Ph.D., and colleagues from the Centers for Disease Control and Prevention in Atlanta, reported on the efficacy of clinical breast examinations (CBEs) in screening for breast cancer. While the use of mammograms for cancer detection has been widely publicized and studied, the use of CBEs for this purpose has not been documented.

Their research, published in the June 21, 2000, issue of the Journal of the National Cancer Institute, suggests that CBEs may aid in the efforts toward early detection of breast cancer. The researchers analyzed data from the National Breast and Cervical Cancer Early Detection Program, which provided CBEs to more than 750,000 low-income women between 1995 and 1998.

About 74% of the records included mammograms as well as results of the CBE and thus allowed for comparison of the two screening methods. “The cancer-detection rate among records reporting an abnormal CBE and normal mammography was 7.4 cancers per 1000 records,” they report. “When the CBE was normal but the mammography was abnormal, the rate was 42.0 cancers per 1000 records.”

While mammography is clearly effective in revealing cancer, Bobo and colleagues conclude that CBEs offered as a screening technique in breast cancer detection programs “may modestly improve early-detection campaigns.”

While Bobo’s research suggests the importance of the old hands-on approach to diagnosis, another study examines the expanding possibilities of medical technology. Ruey-Feng Chang, Ph.D., and colleagues from the Department of Computer Science and Information Engineering of National Chung Cheng University in Taiwan looked at computer-aided diagnosis for breast lumps thought to be malignant.

This study, published in the June 2000 issue of the Archives of Surgery, notes that ultrasound (US) has become “the most useful adjunctive technique to mammography” in evaluating breast masses. Ultrasound uses high-frequency sound waves to produce a picture of tissue inside the body. Chang and colleagues used a computer-aided diagnostic (CAD) system to analyze results of digital ultrasound studies of breast masses. They found that the CAD system diagnosed breast cancer with an accuracy rate of 90%, slightly better than the accuracy of an experienced radiologist.

When a surgeon is unsure about the significance of US findings, the CAD system can quickly provide a second opinion about the diagnosis. And use of the system would be easy to implement: “For most available diagnostic digital US machines, all that would be required for the CAD system is only a personal computer loaded with CAD software.”

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