Breast cancer is the most common cancer in women all over the world, and it is also the main cause of cancer death in women. In 2018, there were about 2.09 million of new breast cancer cases and 630 thousand of death cases worldwide. The incidence rate of breast cancer varies in different regions of the world, but all of them were on the rise. Although the incidence (36.1/10⁵) and mortality (8.8/10⁵) of female breast cancer in China were relatively low worldwide, the number of female breast cancer cases and deaths in China ranks first in the world. Moreover, the incidence and mortality of female breast cancer in China are increasing in recent year. Breast cancer is a multifactorial disease, mainly including genetic factors, environmental factors and behavioral lifestyle factors, etc. This review aims to explore the epidemiology and related risk factors of breast cancer in the world, so as to understand the prevalence of breast cancer and provide help for the prevention, intervention and early detection of breast cancer.

Lung cancer is the most common malignant tumor in the world. The five-year survival rate is 19.7%, which seriously threatens human health. Lung cancer screening is an effective measure to reduce lung cancer mortality. Existing studies have shown that screening with low-dose computed tomography (LDCT) can reduce lung cancer deaths by 20%. Currently, lung cancer screening is recommended internationally and nationally. Studying the development status of lung cancer screening helps us to identify the high-risk groups of lung cancer, explore reasonable screening programs, improve the cost-effectiveness of screening and reduce the economic burden. Therefore, this article summarizes the current status of lung cancer screening, the cost-effectiveness of lung cancer screening and the existing problems as follows.
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