The Fashion Police star decided to have the procedure in hopes of becoming cancer-free.
On Tuesday (December 27), Rancic tweeted that she was at work for the first time since the surgery.
"Back at work today since surgery," she wrote. "Excited to be on set of @ENews. I've missed my 2nd family (co-workers and you guys!!!) #thankful (sic)."
Rancic confirmed that she had been diagnosed with an early stage breast cancer in October.
Earlier this month, she was said to be "doing really well" in the wake of the procedure.