CHAPTER ONE

 INTRODUCTION

BACKGROUND OF STUDY

Breast cancer is the most common type of cancer in females and the leading cause of cancer morbidity and mortality world-wide. The incidence of breast cancer is rising rapidly as well as its mortality rate. It is a malignant tumour that develops from the breast cells. It usually starts from the inner lining of milk ducts or lobules that supply them with milk. Breast cancer incidence is rising rapidly, as a result, it has become one of the major focus of scientific research and its screening is now of great importance.

The incidence, prognosis and survival rate of breast cancer varies greatly around the world. The prognosis and survival rate depend on the stage of at diagnosis and the geographical location of the patient; in the Western world the survival rate is high but low in the developing countries,(National cancer institute, 2011;American cancer society,2003).

According to the National Cancer Institute,(2011), about 232,340 female breast cancer and 2,240 male breast cancer are reported in the USA each year, as well as about 39,620 deaths caused by the disease. It accounts for 16% of all female cancer and 22.9% of invasive cancers in women, and18.2% of all cancer deaths world-wide including both males and females are from breast cancer (Menson, 2014). The incidence of breast cancer has shown an upward trend in younger women. Globally, breast cancer is the most common malignant neoplasm among women.In Egypt, breast cancer accounts for 35.1% of the cases of cancer and is the most prevalent cancer among Egyptian women; the median age at diagnosis for breast cancer is ten years younger than in the United States and Europe (Abdulla, 2011). According to World Health Organization report there were about 519,000 women who die from breast cancer annually and more new cases are found, which is estimated to be one million of women develop breast cancer each year approximately (WHO, 2013;Afaf et al,2015).

It has been reported that more than 80,000 new cases of breast cancer are detected world-wide and the disease claims more than 35,000 lives every year, a rise of about 18% since 1990 (Menson, 2001).