CHICAGO (CBS) — The Northwestern Memorial Hospital cancer specialist who treated former First Lady Maggie Daley is leaving Chicago to go to Los Angeles.

Dr. Steven Rosen has been director of Northwestern’s Robert H. Lurie Comprehensive Cancer Center for 24 years.

Now, at age 61, he is going to the City of Hope Hospital in Los Angeles, where he’ll be provost and scientific director at the institution, which is renowned for its cancer treatment center.

“I feel that at this juncture, there’s an opportunity for me to do something very special at City of Hope,” Rosen said. “There’s also some personal ties to California. I have two children, my parents and a sister living out there.”

Rosen said he still sees the Daley family on a regular basis.

“I have wonderful memories of Maggie and our times together,” he said.

Northwestern is conducting a nationwide search for Rosen’s replacement.

Rosen will be staying at Northwestern through January.