E! News anchor Giuliana Rancic announced this morning on “The Today Show” that she will undergo a double mastectomy followed by reconstructive surgery next week.

The TV hostess, 37, revealed she had breast cancer in October and had a double lumpectomy later that month.   But her husband, Bill Rancic, said the couple learned during a subsequent doctor’s visit that the cancer didn’t completely clear out of one breast.

Dr. Marisa Weiss, president and founder of Breastcancer.org, said a mastectomy may be medically necessary in cases where doctors can’t remove the entire lump.

“For someone with early-stage breast cancer, having a lumpectomy with radiation is equally as effective as a mastectomy, but only if doctors can get clear around the lump.”

Many women, Weiss explained, may then choose to have the other breast removed in order to prevent cancer on that side, or if they already had cancer that was removed, to prevent it from coming back.

“With the double mastectomy, I have less than a 1 percent chance of getting it back. With another lumpectomy, radiation and medication, I could have seen 20 to 30 to 40 percent chance in my lifetime and for me it just wasn’t worth it,” Giuliana said.

Another reason for her decision, Giuliana revealed, is the couple’s desire to have a child.  They have publicly struggled with infertility for a long time.

“If I had chosen to just do another lumpectomy and then do radiation and then do anti-estrogen therapy, which means two to five years of medication, that basically puts me into early menopause, then I would have to put off having a baby for several years,” she said.

Rancic also wants to send out a positive message to other women that instead of being something to be ashamed of, a mastectomy is a life-saving operation.

“When they first told me mastectomy was an option, I said, ‘Absolutely not. Absolutely not. I am 37 years old. I don’t want to do it’ because to me, the word was very scary and it meant I would be disfigured.”

But a close friend had the same operation, and she realized that women in that situation can be beautiful, healthy and positive, a message Rancic said is important for women.

Above all else, however, the couple said while not all women in Rancic’s situation may opt for a double mastectomy, it was the right decision for her.

“It came down to was just choosing to live and not looking over my shoulder for the rest of my life.”