Rise in large breast tumors seen among white women in US

In the 1990s, a small but unexpected rise in the incidence of large breast cancers was observed among white women in the US, new research reveals. Although large tumors are twice as common in African Americans, rates in this ethnic group remained stable during the same period.

The findings are based on a study conducted by Dr. Michael Thun and colleagues at the American Cancer Society in Atlanta. Data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results program and from the National Center for Health Statistics were analyzed to assess recent breast cancer trends by ethnicity.This year, the researchers predict 211,300 new cases of invasive breast cancer, 55,700 in situ cases, and 39,800 deaths among women in the US. The new findings are reported in the November/December issue of CA: A Cancer Journal for Clinicians. Since the early 1980s, an increase in breast cancer rates was observed among all women combined, the authors note. These rates have stabilized for African American women since 1992, but continued to rise in other ethnic groups except American Indians/Alaska Natives. In the latter group, a drop in rates actually occurred between 1992 and 2000. The rates of large tumors (> 5 cm) among white women increased from 5.6 to 6.3 cases per 100,000 between 1992 and 2000, the authors note. Although this finding is partially responsible for the overall increase in cancer rates, a rise in small and localized-stage tumors was mainly to blame for the overall trend in white women.With the exception of small (no greater than 2 cm) tumors, all other tumor sizes were more commonly seen in African American women than white women. In addition, African Americans were more likely to be diagnosed with distant-stage disease than whites.Other ethnic groups had lower breast cancer rates than African Americans or whites. However, compared with whites, all other ethnic groups were more likely to have their disease diagnosed at an advanced stage and with larger tumor size.Despite the rise in breast cancer rates, mortality from the malignancy has actually dropped since the early 1990s. For whites, mortality fell by 2.5% per year, whereas for African Americans the annual drop was more modest-1%. By 2000, ethnic differences in mortality trends resulted in a 32% higher death rate for African Americans compared with whites. Currently, 63% of breast cancers are diagnosed at a local stage and 29% are diagnosed at a regional stage, the authors note. The corresponding 5-year survival rates are 97% and 79%. “Although continued research is needed on the causes, prevention, and treatment of breast cancer, much progress can be made by applying current knowledge fully and equitably to all segments of the population,” the researchers conclude.(Source: CA Cancer J Clin 2003;53:342-355: Reuters Health: November 19, 2003: Oncolink)