Twenty-five years ago, cancer was almost a different disease. Despite the so-called War on Cancer, declared in 1971 by President Richard Nixon, treatments had mostly remained the same blunt instruments — brutal chemotherapy, surgery and radiation. It seemed as if cancer had won the war.

Now, cancer medicine is in a new place. An increasing array of treatments precisely target the cancer itself. And for some cancers, researchers have learned to direct the immune system to kill the malignant cells. Cures are possible for some cancers that had seemed incurable. Many patients can live longer and better lives than ever seemed possible. Cancer death rates have been plunging, and researchers attribute most of that to improved treatments.

Overseeing this change at the Food and Drug Administration has been Dr. Richard Pazdur, currently the director of the Oncology Center of Excellence. Trained as an oncologist, he leads the agency and its cancer specialists in determining how cancer drugs are tested and approved.

Through 25 years at the agency in a variety of roles, he has been present from the start of the new era and has seen firsthand how scientific discoveries completely changed the prospects for many cancer patients. In two edited and condensed conversations, he discussed what he has seen, and what he hopes for.

What was it like to be a cancer doctor when you first began, and what has changed?

When I started in medical oncology in 1979, we had less than 40 oncology drugs for all cancers. I came to the F.D.A. in 1999, thinking that most drug development would be done by the National Cancer Institute. I thought industry would have very little interest because most drugs were short course with excessive toxicity and many patients had a poor prognosis.

I couldn’t have been more wrong. For many patients, things have changed dramatically. From 1999 until the present,we approved 201 cancer drugs. When I came to the F.D.A. there were about 10 medical oncologists at the agency. Now there are 100.