Rates of breast biopsy remained stable over a 12 year period even as mammogram use increased

Rates of breast biopsy (removal of tissue for diagnostic evaluation) remained stable over a 12 year period even as mammogram use increased and new and less invasive biopsy techniques were introduced, according to a study in the July 25 issue of Archives of Internal Medicine.

Changes in the guidelines for breast cancer screening have resulted in increased use of mammography. However, some women screened by mammography may have a false positive result, requiring further tests, including biopsy, resulting in anxiety, inconveniences and trauma for the patient as well as increased costs, according to background information in the article. Further, the authors suggest, the advent of less invasive breast biopsy techniques might also contribute to an increase in the use of biopsy, but there is little information on the actual frequency of biopsy in the general community.

Karthik Ghosh, M.D., M.S., of the Mayo Clinic, Rochester, Minn., and colleagues, reviewed the medical records of women 18 years and older from January 1, 1988 through December 31, 1999, using the resources of the Rochester Epidemiology Project which indexes all inpatient and outpatient medical care provided to residents of Olmsted County, Minn. The rate of utilization of biopsy was calculated as the number of biopsies performed (except when multiple biopsies were performed on the same breast at one time) compared with the number of women in Olmsted County.

The researchers identified 2,878 biopsies performed on 2,521 women residing in Olmsted County during the study period. "The overall, age-adjusted, annual utilization rate of breast biopsies was 62.6 percent per 10,000 women and remained fairly constant throughout the study period," the authors write. "There was no significant change in the trends in breast biopsy utilization before or after the introduction of the core-needle breast biopsy procedure in 1992. Utilization rates for women aged 18 to 39 years, 40 to 49 years, and 50 years and older remained stable throughout the study period. … The rate of utilization did not change in the 40- to 49-year age group despite the introduction of regular screening mammography guidelines in this group in 1997." The researchers found that the ratio between results that indicated a malignancy [cancer] and those that did not [benign] remained stable throughout the study at one malignancy for every 2.2 benign results.

"In conclusion, this population-based study is an assessment of clinical breast practice across a 12-year period during which there was increasing use of mammography and the introduction of new, less invasive biopsy techniques, presumably increasing breast biopsy utilization," the authors write. "Breast biopsy utilization rates remained stable throughout the study, although the biopsy technique itself changed with increasing utilization of image-guided core-needle biopsies. The benign-malignant ratio also remained stable despite the change in biopsy techniques. A multidisciplinary breast practice, along with established guidelines for breast biopsy, can ensure the appropriate use of new technology and thereby improve patient care."