Complex sentence: Having been treated twice for a malignant brain tumor, he is a leading figure in his engagement for integrative approaches to the prevention and treatment of cancer; he popularizes his knowledge through teaching seminars, lectures, books, a blog and audio books.
Split into simpler sentences: Having been treated twice for a malignant brain tumor, he became a leading figure in his engagement for integrative approaches to the prevention and treatment of cancer. He popularized his knowledge through teaching seminars, lectures, books, a blog and audio books.