Saturday, 17 May 2008

MRI increases mastectomy rate

Two interesting stories hit the headlines this week. The first concerned breast density, and the fact that passing through the menopause can greatly affect the rate at which a woman's mammographic (breast) density changes over time.
This was a report from the American Journal of Epidemiology
Am. J. Epidemiol. 2008 167: 1027-1036

The researchers retrieved and digitized 5698 mammograms from 1689 women who were imaged in 1990-2003 to evaluate PD in the Minnesota Breast Cancer Family cohort. The women completed two questionnaires, the first in 1990-1996 and the second in 2001, which provided extensive risk factor data. Postmenopausal women showed a decline in PD of 1.0% over a mean of 6.2 years, while premenopausal women showed a decline in PD of 1.8% over a mean of 4.0 years.

Further analysis showed that, before the age of 50 years, postmenopausal women who never used hormones had a higher PD compared with former and current users. After the age of 50 years, women who never used hormones had larger declines in PD than current or former users.

Higher BMI was associated with lower PD among postmenopausal women at any age after adjusting for covariates. And women in the 95th (highest) percentile for baseline PD showed greater declines in PD over time than women in the 5th (lowest) percentile.

You can get a FREE PDF of the paper from - here

The other story was widely reported in the NEW YORK TIMES this Friday. Thanks to press releases, details about the study which will be presented in Chicago at the annual meeting of the American Society of Clinical Oncology, which begins May 30 has got into the media.

The study revealed that "the percentage of women opting for mastectomy rather than lumpectomy began rising sharply after 2003." A possible explanation for the increase is that MRI "detects more possibly cancerous growths than mammography," which "could be causing patients and doctors to conclude that a lumpectomy, which removes just the part of the breast containing the primary tumor, may not be sufficient."

We certainly are doing far more MRIs, but in our case at UCSF, many of these patients are in trials. Wait until we start following the American Cancer Society Guidelines for women at high risk of breast cancer, with the increase in false positives we get, plus the increased anxiety because of family history...........