To the Editor: Dr Johnson and colleagues1 concluded that there has been a significant increase in the incidence of ER+ breast cancer with distant involvement for women aged 25 to 39 years between 1976 and 2009 and urged further study of potential causes. An increase in childhood and adolescent non-Hodgkin lymphoma (NHL) began around the same time and was recognized in the late 1990s, with similar questions raised about causes.2
Cramer DW, Finn OJ. Incidence Rate of Breast Cancer in Young Women. JAMA. 2013;309(23):2433. doi:10.1001/jama.2013.6450
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