Lung cancer has now surpassed breast cancer as the leading cause of cancer deaths in American women. In 1986, 49,000 women were diagnosed as having lung cancer; only 16 percent of them will survive 5 years or more. Cigarette smoking is unquestionably the leading contributing factor. Large numbers of women took up cigarette smoking during and after World War II. The grim aftermath has taken 20 years to surface--between 1950 and 1985, lung cancer deaths in women increased 500 percent. Even worse, statistics to the end of this century will show no improvement because of the large number of teenage girls and young women now smoking. Unfortunately, efforts at early diagnosis have usually been ineffective. By the time a chest X-ray reveals an abnormality, the patient is usually incurable. Surgery is currently the primary treatment, but is applicable only to those few women in whom the cancer has not spread and who are otherwise acceptable surgical candidates. Scientists are studying chemotherapy and immunotherapy for treatment, as well as exploring the possible preventive effects of various vitamins and minerals. The results of these latter studies will not be available for many years. It is estimated that people who stop smoking must allow 15 years for their risk to return to that of nonsmokers, but if every American woman gave up smoking today, by 2017 lung cancer in women might once again be a medical rarity.