Adding to the confusion has been the excitement over surgical innovations, particularly “nipple-sparing” mastectomies. During a traditional mastectomy, doctors remove the nipple and scoop out breast tissue, causing considerable nerve damage. But now, in certain cases, the nipple can be spared, raising hopes that some feeling will be preserved.

The actress Angelina Jolie wrote about her nipple-sparing, preventive double mastectomy in a New York Times Op-Ed in 2013, inspiring other women at high risk of breast cancer to have their breasts removed. But the nipple-sparing surgery has yet to fulfill its promise, and in most cases, sensation is not restored.

For many women, the loss of sensation in their breasts can be devastating.

“No one said, ‘You will not have sexual arousal in your chest again,’” Ms. McCree said. “I thought that because I was able to keep my nipples and the blood supply, I’d keep my feeling.”

Eve Wallinga, 60, a cancer survivor from St. Cloud, Minn., said many women who choose risk-reducing mastectomies believe that reconstructive surgery will make them “whole” again and are not told that the sensation lost during the surgery is unlikely to come back.

“They go into it thinking everything will be the same when they come out — they’ll just have cancer-proof stuffing in their breasts,” Ms. Wallinga said. “Some are very angry and upset, and say, ‘Why wasn’t I told?’ They feel very betrayed.”

The lack of sensation is potentially dangerous. Women who have had mastectomies and reconstruction surgery have sustained severe burns on their breasts from heating pads, hair dryers, curling irons, sunbathing and overly hot showers.