Sheryl Crow: Strong Enough

03/02/2006 at 12:00 PM EST

Not unlike her former fiancé, who has been in contact with Crow – as well as her family and doctor – since her diagnosis. "He's been involved with people in his organization and in touch with certain doctors to see who's best to treat Sheryl," says the source close to the singer. Although the source says it's unlikely they've been spending time together again, "they've been in touch either via phone or e-mail. He's been very supportive. He's extremely concerned."

Even before her 2 1/2-year relationship with Armstrong, Crow was an outspoken advocate for cancer activism. Now her own diagnosis has only strengthened her focus to spread the word about early detection. "Sheryl and I have talked about the opportunity she has now to promote health care among women, and that everyone should seek the best possible medical care," says Ulman, himself a three-time cancer survivor. "She is trying to make the point that early detection is the key to survival."

Adds Natalie Cole, a friend of Crow's and a fellow cancer activist (her father died of lung cancer in 1965): "I know she'll get through this. The same resolve she has used to deal with her breakup is the same she'll use to deal with this."

Despite the postponed tour, Crow – whose introspective latest album, the Grammy-nominated Wildflower, showcases a quieter, more raw sound – has no plans to put down her guitar for long. "She's already asking when they can hit the road again," says Trott. "She is ready to go."

• By Michelle Tauber. Alicia Dennis in Austin, Carrie Borzillo-Vrenna, Michael Fleeman and Vicki Sheff-Cahan in Los Angeles, and Kate Klise in Chicago