Clinical Breast Cancer December 2005 • 391 Introduction Approximately 1.15 million new cases of breast cancer were diagnosed in 2002, which is more than the combined inci- dence of colorectal and cervix uteri cancer, the second and third most common cancers in women, respectively. 1 Breast cancer is the most common cause of cancer-related mortality among women, accounting for approximately 411,000 deaths each year, 1 which is approximately 15% of all cancer-related deaths. 2 With the lifetime risk of developing breast cancer as high as 1 in 8 women in some Western countries 3 and a 5-year prevalence of approximately 4.4 million cases worldwide, 1 the global burden of breast cancer is substantial. However, the burden is not evenly distributed worldwide: there are large variations in the incidence, mortality, and survival between different countries, regions, and within specific regions. This review will provide an overview of recent breast can- cer epidemiology statistics and trends and will further ex- plore some of the possible explanations of why these vary so greatly. Breast cancer incidence (the number of new cases arising in a given period in a specified population, usually an absolute number of cases per year or the rate per 100,000 persons per year), mortality (the number of deaths occurring in a given period in a specified population, usually an ab- solute number of deaths per year or as a rate per 100,000 population), and survival (the probability of survival, ex- Submitted: Jun 9, 2005; Revised: Aug 22, 2005; Accepted: Aug 23, 2005 1 The University of Texas M. D. Anderson Cancer Center, Houston 2 Instituto Nacional de Cancerologia, Mexico City, Mexico 3 Toronto–Sunnybrook Regional Cancer Center, ON, Canada 4 Pierantoni Hospital, Forli, Italy 5 Brustkrebs-Muenchen e.V. and Brustkrebs Deutschland e.V. (German Breast Cancer Association), Germany 6 Memorial Sloan-Kettering Cancer Center, New York, NY 7 National Cancer Institute, Cairo, Egypt 8 Sun Yat-Sen Cancer Center, Aioei, Taiwan 9 Hospital Universitario San Carlos, Madrid, Spain 10 Center Antoine Lacassagne, Nice, France 11 Baylor Sammons Cancer Center, US Oncology, Dallas, TX 12 FuDan University, Shanghai, China 13 Loyola University Chicago Medical Center, Cardinal Bernardin Cancer Center, Maywood, IL Address for correspondence: Gabriel N. Hortobagyi, MD, Department of Breast Medical Oncology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd, Unit 424, Houston, TX 77030-4009 Fax: 713-794-4385; e-mail: ghortoba@mdanderson.org The Global Breast Cancer Burden: Variations in Epidemiology and Survival Breast cancer is the most common type of cancer and the most common cause of cancer-related mortality among women worldwide. However, the burden is not evenly distributed, and, according to the best avail- able data, there are large variations in the incidence, mortality, and survival between different countries and regions and within specific regions. Many complex factors underlie these variations, including population structure (eg, age, race, and ethnicity), lifestyle, environment, socioeconomic status, risk factor prevalence, mammography use, disease stage at diagnosis, and access to high-quality care. We review recent breast cancer incidence and mortality statistics and explore why these vary so greatly across the world. Further re- search is needed to fully understand the reasons for variations in breast cancer outcomes. This will aid the development of tailored strategies to improve outcomes in general as well as the standard of care for un- derserved populations and reduce the burden of breast cancer worldwide. Clinical Breast Cancer, Vol. 6, No. 5, 391-401, 2005 Key words: Incidence, Mortality, Outcomes review Abstract comprehensive Gabriel N. Hortobagyi, 1 Jaime de la Garza Salazar, 2 Kathleen Pritchard, 3 Dino Amadori, 4 Renate Haidinger, 5 Clifford A. Hudis, 6 Hussein Khaled, 7 Mei-Ching Liu, 8 Miguel Martin, 9 Moise Namer, 10 Joyce A. O’Shaughnessy, 11 Zhen Zhou Shen, 12 Kathy S. Albain, 13 on Behalf of the ABREAST Investigators Electronic forwarding or copying is a violation of US and International Copyright Laws. Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by Cancer Information Group, ISSN #1526-8209, provided the appropriate fee is paid directly to Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923 USA 978-750-8400.