PRINCIPAL CANCERS AMONG WOMEN - BREAST, LUNG AND COLORECTAL

The major variations in the pattern and level of cancer throughout the world reflect for the most part differences in the environment. It is generally agreed that carcinogenesis may arise as a result of chemica l, physical, biologic, and genetic insults to cells. In addition, spec ific external factors may initiate and/or support malignant transforma tion, such as smoking, occupational and environmental chemicals, radia tion, dietary factors, and specific viruses. Furthermore, endogenous c ompounds, such as steroid sex hormones, may be promoters for carcinoge nesis of hormone-dependent tissue. Although some cancers seem to be re lated to inherited traits, research generally does not support the not ion of group or inherited differences in cancer statistics. The leadin g causes of cancer death in females in 1981 in the United states were lung cancer (52,068), breast cancer (43,583), and colorectal cancer (2 9,017). According to the American Cancer Society, this year 182,000 wo men will be diagnosed with breast cancer, 73,900 with lung cancer, and 66,000 with colorectal cancer. Even with our knowledge about the infl uence of life style and environmental causes of cancer, little progres s has been made. In breast cancer, only 25 to 30% can be attributed to known risk factors. Lung cancer in females, on the other hand, once a rare disease, turns out to be the leading cause of cancer death among women in industrialized countries, mostly due to smoking.