San Francisco Symphony Conductor Michael Tilson Thomas’ brain tumor has returned, he says, and the 80-year-old intends to lead his final performance in April.

After three years since announcing his initial diagnosis, San Francisco Symphony Music Director Laureate Michael Tilson Thomas’ glioblastoma brain tumor has returned, forcing the longtime conductor to officially step down from performing.

Former San Francisco Symphony director and globally celebrated conductor Michael Tilson Thomas announced on Monday that his brain tumor has returned.