Scientific progress is erratic, unpredictable. "We are all foundering around in the dark," said Peter B. Bach, director of the Center for Health Policy and Outcomes at Memorial Sloan-Kettering Cancer Center. "The one thing I can tell you is some of that foundering has borne fruit." There are the few therapies, he said — like tamoxifen and Herceptin — that target specific tumor characteristics, and newer tests that estimate the chance of recurrence in estrogen-positive cancers, allowing lower-risk women to skip chemotherapy. "That's not curing cancer," Bach said, "but it's progress. And yes, it's slow."