Although information about the rising incidence of second cancers was published in 2014, the media took notice of this in August 2015 and widely publicized the statistic that 19%—or nearly a fifth—of cancer diagnosed today occur among people with a history of a previous cancer. Among childhood cancer survivors, the most commonly diagnosed second cancers are nonmelanoma skin cancer and cancers of the breast, CNS, and thyroid. It’s likely that radiotherapy, and perhaps chemotherapy to a lesser extent, cause or contribute to the development of cancer among childhood cancer survivors. Second cancers among adults are more complex and multifactorial in their etiology, with lifestyle and environmental factors playing a major role in their development.
More people are developing second cancers for several reasons. The biggest reason is that more people than ever are surviving their initial cancer diagnosis and living long enough to develop a second cancer. Aging of the population allows more time for a second cancer to develop. Lifestyle factors, such as obesity, nutrition, and smoking, are becoming more prevalent in the development of second cancers. The incidence of second cancers in our population has clinical as well as public health implications, and more research is needed to identify people most at risk for the development of second cancers and implement targeted screening programs.
Morton LM, Onel K, Curtis RE, et al. The rising incidence of second cancers: patterns of occurrence and identification of risk factors for children and adults. 2014 ASCO Educational Book, e57-e67.