From his website:
She can’t be dead. But she is: she died yesterday morning. Cancer. I had no idea she was ill; she was so private, never wanted any fuss, and now, gone. A terrible blow to her friends and a shattering blow for all those fans of the programme whose lives were touched every Saturday evening by her lovely heroic character, Sarah-Jane Smith.
Lis Sladen was very important to me, you know. When I joined the little world of Doctor Who, Lis was already a star. She had an enormous success with Jon Pertwee. She was good pals with the Brigadier, our beloved Nicholas Courtney; she knew all the regular directors. She was adored by Barry Letts, the producer who cast her in the role. She always said she was Barry’s girl. It was for that reason she decided to leave the show. But it was not necessary at all. The fans adored her, Philip Hinchcliffe, our new and glamorous producer, adored her, so did David Maloney, her favourite director.
Terry Walsh, the regular stunt man adored her. Once in deep, dark Wooky Hole caves Lis was almost swept away in a small boat, fifty feet from a terrifying black hole that looked like the entrance to hell. In a flash Terry Walsh dived in and caught the boat and all was well, thanks to the devotion of Terry. Lis was safe and and the show could go on.