Despite an email rumor, there are no strong epidemiologic studies that show a link between parabens in antiperspirants and breast cancer, according to the American Cancer Society. Other claims in this email, including the claim that women who use antiperspirants and who shave their armpits have a higher incidence of breast cancer in the upper outer quadrant near the armpit, are also unsupported.
A study performed in 2002 asked questions of 813 women with breast cancer and 793 without breast cancer to look for a link between armpit shaving, antiperspirant use and deodorant use, reports the American Cancer Society. This study found no link. Another study, from 2003, claimed to find a correlation between cancer diagnosis at a younger age and more frequent armpit shaving, earlier armpit shaving and antiperspirant use. However, this study did not have a control group and received further criticism for other reasons.
Parabens have weak estrogen-like effects in the body that might cause concern, as estrogen causes breast cells to grow and divide. Higher levels of estrogen also have links to a higher incidence of breast cancer, explains the American Cancer Society. However, parabens are hundreds or thousands of times weaker than estrogens, and no legitimate studies have shown a causal link between parabens and breast cancer.