text: why should i be concerned about lung cancer?   researchers continue to study the causes of lung cancer and to search for ways to prevent  it. but, about 90% of all lung cancer deaths among women are from smoking. even though  we know its effects are harmful, 1 out of every 5 women in the u.s. still smokes. we already  know that the best way to prevent lung cancer is to quit (or never start) smoking. the soone r a person quits smoking the better. even if you have been smoking for many years, it's never  too late to benefit from quitting