When he was diagnosed with a malignant brain tumor 20 years ago, David Servan-Schreiber, the French-born doctor, neuroscientist and later bestselling author, took the phrase "physician, heal thyself" to heart.

Submitting to the punishing traditional treatments of chemotherapy and radiotherapy, he still felt there was something more he could do to enhance his chances of survival.

Armed with his will to live and a belief that the human body had little-known cancer-combating capacities of its own, he set about looking into the way we understand and battle the disease.

From his research came the successful book "Anticancer: A New Way of Life," published in 2007, that sold 1 million copies and led to a sea change in how cancer was viewed and treated.

Servan-Schreiber's near two-decade exploration of the science of cancer was a personal and professional journey that took him from the verge of death to good health and back again twice before ending in his death Sunday at a hospital near his family's home in Normandy. He was 50.

Even when told last year that the brain cancer had returned and would almost certainly kill him this time, Servan-Schreiber refused to give in, continuing to promote the idea that, parallel to traditional medicine, healthy eating along with meditation, yoga and "a new way of life" could extend the lives of cancer sufferers.

David Servan-Schreiber was born in the wealthy Paris suburb of Neuilly-sur-Seine on April 21, 1961, the son of a celebrated French family with Prussian Jewish roots. David was the eldest son of Jean-Jacques Servan-Schreiber, a respected journalist, essayist and politician, who died in 2006.

He studied medicine at a children's hospital in Paris, finishing his medical degree at Laval University in Quebec in 1984 before specializing in psychiatry in Montreal and moving to a research post at Carnegie Mellon University in Pittsburgh, where he earned his doctorate.

In 1991 he went to Iraq as a volunteer medic with the French-based Doctors Without Borders, the nongovernmental organization that won the Nobel Peace Prize in 1999, and later co-founded the U.S. branch of the charity.

The story goes that he discovered he had a brain tumor only when in 1991 a research patient failed to turn up for an MRI scan and Servan-Schreiber took his place.

He underwent treatment but had a relapse a few years later and began to seriously turn his mind and his work to the effects of diet and lifestyle on the incidences of cancer and depression.

His first book, "Healing Without Freud or Prozac," published in 2003, was translated into 29 languages and sold 1.3 million copies. "Anticancer" followed four years later.

Certain critics dismissed Servan-Schreiber as a "new age guru" who proposed quack theories that more vegetables, more exercise and less stress were a cure for cancer. On the contrary, he was quick to admit that traditional methods such as chemotherapy and radiotherapy were the first and most important salvos in the battle against the disease. However, he believed the body harbored a number of natural defenses that could create a terrain in which cancer would find it hard to thrive.

Said Ursula Gauthier, journalist and coauthor of his last book, "We Can Say Goodbye Several Times": "He wasn't a great thinker, a philosopher or a mandarin of science or medicine. He described himself as a scientist and a human. He was a mixture of heart and head, intellect and emotion."

Servan-Schreiber was told his cancer had returned when a brain tumor, which he called the Big One, was diagnosed in May 2010.

At the time he said: "Death is part of life. It happens to everyone. Profit from now, do the important things.

"I am convinced that 'Anticancer' has played an important role in the fact that I survived cancer for 19 years when the first diagnosis gave me only six at the most."

Survivors include his wife, Olga Tereshko, and a son, Alexandre.