The 45-year-old actress, of “ER” fame, has already filmed scenes for the upcoming seventh series. She will reprise her role as Kelly McPhee.
Christina Papadopoulos, a spokesperson for Tierney, said “She has finished treatment and is doing very well and is happy to move forward with the next phase of her life."
Tierney, who played one of Tommy’s (Denis Leary) three love interests, moved on from “Rescue Me” when she landed a role on NBC’s “Parenthood”.
Having dropped out of that role to undergo cancer treatment she returned to the stage in February with the play “North Atlantic” in Los Angeles.
Peter Tolan the joint creator and executive producer of “Rescue Me” said “We loved working with her — that was kind of a big deal to get her. We have a deal where we can use her for four episodes. And since we have that deal, we will take advantage of it.”