The reality star has been recovering at home since surgeons performed a two-hour double lumpectomy and removed lymph nodes for biopsy last Wednesday (19Oct11).
But Rancic proved she's bouncing back after going back to her job as an anchor on entertainment programme E! News on Monday (24Oct11).
She tweeted, "Feels so great to be back at work today. The E News set was such a blast & my friends in the newsroom wore pink ribbons 4 me... THANK YOU from the bottom of my heart for your love & support this past week. Your words got me through this more than you'll ever know."
Meanwhile, actress Elizabeth Hurley, a longtime campaigner for breast cancer awareness, has offered her well wishes to Rancic.
The Brit says, "I think it's really hard to find anyone nowadays who doesn't know somebody that's had breast cancer so, to me, it's a phenomenal cause. And obviously I wish the best of luck to Giuliana and I'm glad her treatment went well. I hope she continues to thrive."