Breast cancer patients treated with lumpectomy and radiation have survival rates as good as those treated with mastectomy, suggests a study showing breast-conserving treatment is most common at teaching hospitals.

-- By 1990, more than 60% of women with localized disease (cancer had not spread to lymph nodes) were getting breast conserving treatment in teaching hospitals vs. about 25% in non-teaching hospitals.

The U.S. banned DDT in 1972, but residues remain in the environment and the chemical still is used elsewhere. Scientists find concentrated residues in human breast tissue and breast milk and fear that the chemical might stimulate cancer in some way. One theory: It may mimic estrogen.