Please note: This content is an excerpt from the American Cancer Society Cancer Facts & Figures 2009 publication. Please download Cancer Facts & Figures 2009 to see all Tables and Figures noted. Any reproduction or re-use should credit the appropriate Cancer Facts & Figures publication and include a statement of copyright and identify the data source used.
In the past three decades, the development of screening tests that prevent and detect some cancers at an early, more treatable stage, and treatment advances have increased the 5-year relative survival rate for all cancers combined from 50% in 1975-1977 to 66% in 1996-2004. The National Cancer Institute (NCI) estimates that there are more than 11 million cancer survivors in the US, more than 3 times the number in 1970. As the survivor population grows, it is increasingly important to address the unique needs of cancer survivors for medical surveillance, continuity of care, and information about how their cancer and its treatment may affect their future health. In addition to concerns about cancer recurrence, survivors also worry about their risk of developing a new cancer.
Approximately 880,300 of the 11 million cancer survivors living in the US as of January 1, 2005, had been diagnosed with more than one cancer. Most of these second or more cancers would be expected to occur even if cancer survivors had the same risk of cancer as the general population. The overall risk of cancer increases with age; for example, it is estimated that only 1% of 30-year-olds with no history of cancer will develop cancer in the next 10 years, compared to 18% of 70 year olds.1 Although cancer survivors as a group have a small (14%) increased lifetime risk of developing new cancers compared with the general population, some subgroups of patients have a much higher risk. The risk of developing subsequent cancers varies by the type of first cancer diagnosed (referred to as the first primary site), age at first diagnosis, environmental exposures, genetic factors, treatment, and other factors. The purpose of this Special Section is to provide information about the burden and risks of multiple primary cancers, which will be useful to cancer survivors in understanding their risks and to health care providers in discussing risks of developing additional cancers with their patients.
This Special Section is organized into several broad topics. First, it provides background information about how clinicians and cancer registries define multiple primary cancers and descriptive statistics about the frequency and risk of subsequent cancers by primary site. It then describes the major factors that cause increased and decreased risk of multiple cancers, including family cancer syndromes and genetic susceptibility factors, shared-risk factors, and effects of treatment of a previous primary cancer. Next, it provides more detail on patterns of subsequent cancers for selected cancer sites (female breast cancer, colon and rectum, tobacco-related cancer, lymphomas, and melanoma) and childhood cancers. The final section describes American Cancer Society programs and resources for cancer survivors, including those who are at increased risk or have been diagnosed with more than one cancer.