Breast cancer is not a single disease; it contains four molecular subtypes, each with a different response to treatment and different survival rates, according to a new report from a group of leading U.S. medical experts. According to the experts, the incidence of these subtypes varies with age, race and many other factors. The report’s authors, including Professor Betsy A. Kohler of the North American Association of Cancer Registries (NAACCR), believe that defining breast cancer by these four subtypes will facilitate the diagnosis and treatment of breast cancer and help patients understand how the diagnosis affects their health. Other than skin cancer, breast cancer is the most common cancer among women in the United States. This year, it is estimated that 231,840 new cases of invasive breast cancer will be diagnosed in the United States and more than 40,000 women will die as a result. In their report, Kohler and colleagues used data from the NAACCR member registry to analyze the incidence of invasive breast cancer among women aged 85 years and younger in 2011. These registries have documented the incidence of four tumor subtypes of breast cancer, defined by hormone receptor status (HR) and human epidermal growth factor receptor 2 (HER2) gene expression, classified as: tubular A (HR+/HER2-), tubular B (HR+/HER2+), HER2 overexpressing (HR-/HER2+) and triple-negative (HR-/ HER2-). Triple-negative breast cancer is most common in non-Hispanic black women With these data, researchers were able to detect for the first time how the incidence of each breast cancer subtype varies with certain factors. For example, it showed that the least invasive breast cancer subtype, HR+/HER2-, was most common in non-Hispanic white women. The team found that for each race, the incidence of this subtype decreased with increasing poverty. Looking at the results by age, the team found that the incidence of HR+/HER2- breast cancer was similar in women younger than 45 years of age for all races. However, among women older than 45 years, this subtype occurred more commonly in non-Hispanic white women than in other races. The researchers found that the most aggressive breast cancer subtype, HR-/HER2-, was most common in non-Hispanic black women. Non-Hispanic black women had the highest rate of advanced breast cancer diagnosis, and the highest type of undifferentiated pathology, among all subtypes. All of these factors are associated with worse survival from breast cancer, which explains why black women have the highest breast cancer mortality rates, the team noted. Dr. Harold Varmus, director of the National Cancer Institute (NCI), said the fact that the report rates breast cancer as four molecular subtypes rather than a single type of disease is a welcome advance. “Relying on important information from medicine, this has been able to guide treatment strategies for these subtypes. In addition, this is a forerunner to more rigorous cancer classification based on molecular characteristics, which is now being aggressively pursued in the President’s Precision Medicine Initiative.” This newly defined diagnostic staging will gradually help us prevent and treat breast cancer and many other cancers, and monitor their incidence and prognosis more rigorously over time. Overall cancer mortality has declined In addition to analyzing the incidence of breast cancer in the United States by subtype, the researchers used data from the NAACCR to assess the incidence and mortality of some of the most predominant cancers and all cancers combined in the United States. They found that between 2002 and 2011, the overall cancer incidence rate decreased by 0.5 percent per year. For men, the overall cancer incidence rate decreased by 1.8% per year between 2007 and 2011. These rates for women remained stable from 1998 to 2011, but cancer rates among children increased by 0.8 percent per year over the last decade. There is some good news about the overall cancer mortality rate. The team found that these incidence rates have decreased since the early 1990s. between 2002 and 2011, the total cancer mortality rate decreased by 1.8 percent per year among men and 1.4 percent per year among women. For children and adolescents 19 years of age and younger, cancer mortality rates have been declining since 1975, including the period from 1998 to 2003. In addition, the report shows that lung and colorectal cancer rates have declined among men and women, which researchers say may reduce smoking rates because of public health interventions. The report also identifies increases in the incidence of thyroid and kidney cancers, as well as increases in the incidence and mortality of liver cancer. ”Decreases in the incidence of lung and colorectal cancers show a role for prevention.” Professor John R. Seffrin, chief executive officer of the American Cancer Society, mentioned. “But we still have a long way to go, and the trend is not very promising not only in these two cancers, but in many others.”