On April 1st, 2004 he was diagnosed with sinonasal undifferentiated cancer, an extremely rare and deadly cancer. He was able to survive in large part due to the interventions of his wife, Katherine Roth M.D. Greg and Katherine have written a detailed account of his cancer treatment in their memoir The Good Fight: A Story of Cancer, Love, and Triumph. The book has been described as a “page-turner, a classic cancer survival story”.