written by Ted Schettler, MD, MPH
As breast cancer awareness month ends with its primary emphasis on early detection I’ve been more interested in what we’ve learned about opportunities for prevention. Amidst all the pink ribbons and disagreements about optimal mammography scheduling an important theme seems to be finally taking hold. Although opportunities abound throughout life, breast cancer prevention begins in the womb.
This idea is not new. Twenty-five years ago Dimitri Trichopoulos proposed that breast cancer risk could originate in utero, influenced by maternal hormone levels. Later studies linked hormone and growth factor levels with populations of breast stem cells in umbilical cord blood—a plausible mechanistic connection to cancer risk. A 2011 analysis reported a nearly two-fold increased risk of breast cancer in daughters of women who took estrogenic diethylstilbestrol (DES) during pregnancy before 1971. This year, Barbara Cohn and colleagues reported that the highest maternal levels of the hormone-disrupting pesticide DDT during pregnancy were associated with a nearly four-fold increased risk of breast cancer in their daughters.