Response—blunting the counterpoint

Mammography screening and breast cancer biology in African American women--a review

This review examines some of the key issues in early detection and breast cancer biology for African American (AA) women which contribute to their diagnoses at more advanced stages than white women, and poorer long-term prognoses. While screening mammography is considered an essential factor in eliminating these disparities, its optimal application for AAs is not fully understood. There is a paucity of information on the success with which mammography screening programs are maintained over time in the AA population, and on screening guidelines with regard to age of initiation and frequency. No randomized clinical trials targeting AA women have been reported. This type of information is critical since breast cancer in AA women occurs at younger ages, and frequently demonstrates aggressive tumor biology at diagnosis. Studies are required to determine the incidence of interval cancers in current screening programs, and the influence of the biological characteristics which are known to differ in the breast tumors of AA and white women. Recognition of molecular and cellular characteristics which identify the potential invasiveness of ductal carcinomas in situ is also required. These studies would assist in establishing the criteria for identifying the subpopulation of younger pre-menopausal AA women who would benefit from early initiation of screening. Finally, the epidemiology and biology of mammographic densities, a risk factor for breast cancer and, perhaps, markers of aggressive disease require further study in both AA and white women.

Is screening mammography effective in elderly women?

PURPOSE

Screening mammography is effective in reducing breast cancer mortality in women between the ages of 50 and 69 years. We sought to determine whether older women who undergo screening mammography have a decreased risk of metastatic breast cancer.

SUBJECTS AND METHODS

We studied 690,993 women aged 66 to 79 years who were California Medicare beneficiaries from January 1992 to December 1993, and who chose the fee-for-service plan. Health Care Financing Administration part B billing records were used to determine the use of screening mammography. The extent of breast cancer (in situ, local, regional, or metastatic) was ascertained for the 6,767 women who were diagnosed with the disease in 1993, using data from the California State Cancer Registry. For each type (extent) of breast cancer, the relative risk (RR) and 95% confidence (CI) of developing breast cancer was estimated by dividing the risk of its development in screened women by the risk in women who were not screened.

RESULTS

A total of 46% of women had mammography during the 2-year study period. In situ, local, and regional breast cancer were more likely to be detected among women who underwent screening mammography. For example, the relative risk of detecting local breast cancer in screened women was 3.3 (95% CI: 3.1 to 3.5). The risk of detecting metastatic breast cancer, on the other hand, was significantly reduced among women aged 66 to 79 years who underwent screening mammography (RR = 0.57, 95% CI: 0.45 to 0.72).

CONCLUSION

Screening mammography is associated with a decreased risk of detecting metastatic breast cancer among elderly women. Public health recommendations need to weigh the benefit of screening elderly women against the cost and potential harm from screening and treating early lesions that may have no effect on mortality.

The role of radiation therapy for primary breast cancer

Radiation therapy for breast cancer has gone through two revolutions in the last two decades: the routine use of radiation therapy in conjunction with breast-conserving surgery as an equivalent treatment to mastectomy, and the use of radiation therapy following mastectomy in advanced or node-positive disease. Indeed, the perception of postmastectomy radiation has gone full circle: from having no benefit when used for all cases, to being detrimental because of cardiac irradiation, to the present in which the selective use of irradiation in high-risk patients provides both an improvement in local control and an improvement of 8% to 10% in the survival rate. Improvements in radiation technique have reduced complications, in particular late cardiac deaths. The major issues still to be resolved are the targets for postmastectomy irradiation, determining which patients do not need radiation therapy for DCIS and for node-negative disease, and the efficacy of delivering radiation to just the affected quadrant rather than to the whole breast. At present, most patients approach radiation therapy for breast cancer with the knowledge that it has a very high probability of being successful.

Outcomes of modern screening mammography

The University of California, San Francisco, Mobile Mammography Screening Program is a low-cost, community-based breast cancer screening program that offers mammography to women of diverse ethnic backgrounds (36% nonwhite) in six counties in northern California. Analysis of data collected on approximately 34,000 screening examinations from this program shows that the positive predictive value and sensitivity of modern screening mammography to be lower for women aged 40 to 49 years compared to women aged 50 and older. This lower performance is due to the lower prevalence of invasive breast cancer in younger women and possibly to age differences in breast tumor biology. Because of this lower performance, women in their forties may be subjected to more of the negative consequences of screening, which include additional diagnostic evaluations and the associated morbidity and anxiety, the potential for detecting and surgically treating clinically insignificant breast lesions, and the false reassurance resulting from normal mammographic results. Since the evidence is not compelling that the benefits of mammography screening outweigh the known risks for women aged 40 to 49 years, women considering mammography screening should be informed of the risks, potential benefits, and limitations of screening mammography, so that they can make individualized decisions based on their personal risk status and utility for the associated risks and potential benefits of screening.