Patti Scialfa, musician and wife of Bruce Springsteen, has been conspicuously absent from much of the E Street Band's latest tour — and now, she has revealed why.

In new documentary, Road Diary: Bruce Springsteen and the E Street Band, which premiered at the Toronto International Film Festival on Sunday night, Scialfa revealed that she was diagnosed with early stage multiple myeloma in 2018 (during the run of Springsteen on Broadway).

While she is doing well, the disease impacts her immune system. "I have to be careful where I go and what I do," she said in the film. "That's my new normal right now."

Scialfa also explained that this is why her presence on the 2023-2024 tour with Springsteen and the band has been significantly diminished. She makes appearances when she can, generally only joining for a few songs, to limit her exposure.

Director Thom Zimny tells Entertainment Weekly there was no master plan to waiting for the documentary to announce Scialfa's health. "I'm not aware of any decision for it to be in the film," Zimny says. "It's coming from a place of spending a lot of time with her talking. I've known her all these years, 24 years...So the theme of why she's not touring came out organically in those conversations."

"I also felt like it touched upon a place of talking about the beauty of her performance in E Street," he continues. "She's an essential part of that sonic quality on the stage. And when I saw her do 'Fire,' I knew that I had to have that in the film. There's a beauty there that in that footage where you see the love of that relationship, but also her place in the E Street [band] too. So it all came about through trust. And for me, that's the best thing that I can have as a filmmaker, and as a friend, is that trust."

Previously, Scialfa told the Asbury Park Press that she had stepped back from the tour to focus on recording a solo album and to spend time with her and Springsteen's first grandchild. "I didn’t feel as needed in a way because there were a lot of musicians on stage,” she said. “I did the first couple of shows, and as I saw how it was all rolling, I thought, 'This is good. This is completely intact. There’s not much room for me to add anything special.' And the main thing was I have a record that I couldn’t have finished when Bruce was home because he’s in the studio all the time. So I took that opportunity to do my record."

But now, Scialfa said in the documentary that her absence is more about mitigating risk factors and protecting her health. Springsteen has had his own health struggles during this tour. He postponed all of his tour dates from September to December 2023 while he was recovering from peptic ulcer disease. He also had to cancel additional dates in Europe this past summer due to "vocal issues" and doctor's orders.

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Scialfa joined the E Street Band in 1984, coming on board as a back-up vocalist only a few days before the start of the Born in the USA tour. She and Springsteen started living together in the late 1980s before they married in 1991.

She has been a part of almost every major Springsteen tour since, taking eleven years off to focus on their family before returning in 2004. She was featured in two numbers in Springsteen on Broadway. Scialfa has also released three solo albums — Rumble Doll, 23rd Street Lullaby, and Play It as It Lays.

Road Diary: Bruce Springsteen and the E Street Band hits Hulu and Disney+ on Oct. 25.