In fighting disease, aggressive action is not always advisable. Two years ago a federal panel recommended against routine use of a test for prostate cancer because it carries “a very small potential benefit and significant potential harms.” Some men get false positives, and many true positives lead to risky surgery for cancers that grow so slowly as to pose no threat.

Then there is power morcellation, which uses a device to shred uterine fibroids. The Food and Drug Administration has warned against its use in hysterectomies because “there is a risk that the procedure will spread the cancerous tissue within the abdomen and pelvis, significantly worsening the patient’s likelihood of long-term survival.”