Women of every age know the threat that breast cancer poses. Girls grow up watching their mothers march against it, and that activism has brought much needed resources and attention to the disease. Yet the cancer that kills more women each year than breast, ovarian and cervical cancers combined is lung cancer. Because it was once mostly a male disease, and because it is associated with smoking, women assume if they never smoked, or if they stopped years ago, they don't need to be on the lookout for this deadly cancer.

But they do. Two-thirds of lung cancer's female victims quit at least a decade earlier or never smoked at all.

Yet the stigma of smoking and the shame people feel for bringing on their illness has caused women to delay seeking medical attention in the early stages of lung cancer. As a result, lung cancer rates have continued to rise, and 23 years ago the disease overtook breast cancer as the leading cause of death in women. Yet who knew?

Stroy By: Eleanor Clift for the Huffington Post Politics Daily (Woman Up)