Diagnosis of breast cancer increases when combination EPT is used beyond 3-5 years. This means that out of 10,000 women who use estrogen progestin therapy for more than 5 years, there will be 8 additional breast cancers diagnosed. In contrast, the WHI study showed women who use estrogen alone had no increase in risk of breast cancer even after 11 years of use. In fact, fewer breast cancers were seen in the group taking estrogen alone, though this was not statistically significant. When a woman comes off of hormone therapy, any potential increase in her risk of breast cancer quickly goes back to her baseline norm. This is why hormone therapy can be a safe option when women in their 50s (who are generally at lower risk for breast cancer compared to older women).