Last Updated: 2007-04-12 14:32:03 -0400 (Reuters Health)
NEW YORK (Reuters Health) - Triple-negative breast cancers - cancers that are estrogen receptor-, human epidermal growth factor receptor 2-, and progesterone receptor-negative - are more common among young, poor minority women, according to results of a study published in the May issue of Cancer. These cancers are often aggressive and are related to poor survival.
"Tumor markers are becoming increasingly important in breast cancer research because of their impact on prognosis, treatment, and survival, and because of their relation to breast cancer subtypes," Dr. Katrina R. Bauer from the Public Health Institute, Sacramento, California, and colleagues write. "The triple-negative phenotype is important because of its relation to the basal-like subtype of breast cancer."
The researchers identified women diagnosed with triple-negative breast cancer between 1999 and 2003 using data from the population-based California Cancer Registry. They compared the demographic, clinical, and survival characteristics of 6370 women with triple-negative breast cancers with 44,704 women with other breast cancers.
The two groups differed significantly in terms of stage at diagnosis. Triple-negative patients presented with a more advanced stage. Patients in the triple-negative group had a significantly larger median tumor size (22 mm versus 17 mm in the placebo group; p < 0.001). Overall, 76% of triple-negative breast cancers were classified as poorly differentiated or undifferentiated, compared to 28% of other breast cancers (p < 0.001).
Patients with triple-negative breast cancers were significantly more likely to be younger than 40 years of age (odds ratio [OR], 1.53). These patients were also significantly more likely to be non-Hispanic black (OR, 1.77) or Hispanic (OR, 1.23). Triple-negative breast cancers were more likely to be diagnosed in women living in areas of lower socioeconomic status.
Women diagnosed with triple-negative breast cancer had poorer survival than those with other breast cancers, regardless of stage at diagnosis. "Non-Hispanic black women diagnosed at late stage with triple-negative breast cancer had the poorest survival of any other comparable group, with only 14% surviving 5 years after diagnosis, compared with 49% 5-year relative survival among non-Hispanic black women with other breast cancers diagnosed at late stage, as well as 36% survival among non-Hispanic white and 37% among Hispanic women with late stage triple-negative breast cancer," Dr. Bauer's team notes.