about 40% of the overall reduction in cancer death rates in men and is responsible for preventing at least 146,000 lung cancer deaths in men during the time period 1991-2003. Breast cancer The most common cancer among women in the United States is breast cancer (123.7 per 100,000), followed by lung cancer (51.5 per 100,000) and colorectal cancer (33.6 per 100,000), but lung cancer surpasses breast cancer as the leading cause of cancer death among women. Researchers attribute the reduction in breast cancer mortality to improved treatment, including the increased use in adjuvant chemotherapy. Prostate cancer The National Institute of Health (NIH) attributes the increase in the 5-year relative survival of prostate cancer (from 69% in the 1970s to 100% in 2006) to screening and diagnosis and due to the fact that men that participate in screening tend to be healthier and live longer than the average man and testing techniques that are able to detect slow growing cancer before they become life-threatening. Childhood cancer The most common type of cancer among children and adolescents is leukemia, followed by brain and other central nervous system tumors. Survival rates for most childhood cancers have improved, with a notable improvement in acute lymphoblastic leukemia (the most common childhood cancer). Due to improved treatment, the 5-year survival rate for acute lymphoblastic leukemia has increased from less than 10% in the 1960s to about 90% during the time period 2003-2009. Improvements in cancer therapy The improvement in survival rates for many cancers in the last half century is due to improved understanding about the causes of cancer and the availability of new treatment options, which are continually evolving. Where surgery was previously the only option for treatment, cancer is now treated with radiation and chemotherapy, including combination chemotherapy that favors treatment with many drugs over just one. Availability and access to clinical trials has also led to more targeted therapy and improved knowledge of treatment efficacy. There are currently over 60,000 clinical trials related to cancer registered on ClinicalTrials.gov, so novel approaches to cancer treatment are continuing to be developed. The NCI lists over 100 targeted therapies that have been approved for the treatment of 26 different cancer types by the United States Food and Drug Administration. See also Cancer prevalence Cancer survivor References External links Cancer survival rates SEER*Explorer (US) National Cancer Institute (US) Cancer Research UK One and five year survival for