In 1882 an American surgeon named William Steward Halsted popularized what’s now called the radical mastectomy. He didn’t think of the idea—one of the first written proposals for a mastectomy was published by a German surgeon in 1719. But it was Halsted who made invasive removal of breast tissue a mainstream part of cancer treatment, and his version of the surgery involved removing the entire breast, along with the nearby lymph nodes and both pectoral muscles. Removing that much tissue at that period of time, before many of the surgical techniques doctors are now familiar with were developed, often left women severely disfigured.

And with the removal of breasts, or pieces of them, came the demand for cosmetic replacements. In 1874 the U.S. Patent Office issued its first patent for a breast prosthetic, to a man named Frederick Cox. The prosthetic was made up of a cotton casing filled with an inflatable breast pad.

In the following years, women would come to dominate the world of breast replacement patents. In 1904, a woman named Laura Wolfe filed a patent for an “artificial breast pad.” Her version was solid, rather than inflatable, and in her patent she described the three things a woman wanted out of a replacement breast: comfort, appearance, and product quality.

Those three things are, largely, still what women want today, though many opt for surgical replacements rather than padded bras. Breast reconstruction is a highly technical and evolving field that employs techniques and technologies from beyond the typical boundaries of surgery—from stem cells to 3D-printed nipples.

It’s hard to pin down exactly how many people get mastectomies in the United States. According to the Journal of the American Medical Association, about 35 percent of women with early-stage breast cancer will undergo mastectomies. The rate of women with a genetic predisposition for cancer getting preventive mastectomies is hard to determine too, but according to several studies and institutions, that rate is increasing.

Not everyone opts to rebuild afterward. According to one study about 42 percent of women choose reconstruction, and the rest decide to skip it, citing things like not wanting another surgery and a fear of breast implants. And there are still no breast replacements that restore function—so the decision is purely a cosmetic one.

But for those who do want to reconstruct their breasts, options can be grouped into two categories: implant reconstruction and tissue reconstruction, which relocates tissue from elsewhere in the patient’s body. The two procedures can be combined—using a small implant and surrounding it with tissue, for example—and both have advanced a great deal in the past 10 years.

On the implant side, researchers are working to develop new materials that will last longer and feel more natural. Many surgeons are moving away from gel-like implants to so-called “form-stable” ones. These are often called “gummy bear” breast implants, because they’re more solid than their predecessors. “If you cut the standard silicone gel it will flow out very slowly like molasses,” explains Oscar Ochoa, a plastic surgeon at the PRMA Center for Advanced Breast Reconstruction in San Antonio, Texas, “but [with] these new ones, if you cut the implant down the middle, everything just stays where it is.” Gummy bear implants are still made of silicone, but doctors say they feel more realistic, and will keep their shape longer than other implants.

When it comes to tissue-based reconstruction, doctors have gotten better and better at grafting a person’s own tissue onto their breast. This tissue normally comes from the belly, thigh, or butt, and along with it the doctors harvest the skin, fat, and blood vessels, while leaving muscle behind. “So the technology has been focused on leaving everything that is nonessential for the breast in place, and only taking the stuff that’s needed for the tissue reconstruction,” explains Ochoa.

Different surgeons prefer different techniques. Ochoa is a fan of tissue reconstruction. “I’m biased towards it, I firmly believe it’s the best, most high quality reconstruction there is for the long term,” he told me. There are downsides—taking tissue from another part of the body means more incisions for the patient, a longer recovery period, a steep learning curve on the part of the doctor and the need for a larger team of trained medical professionals on hand. But Ochoa points to the downsides to implants too—the long term satisfaction with implants isn’t always high. They can lose their shape and firmness, and even rupture if the implant gets old. When using the patient's own tissue, Ochoa says the results are often better. “If you see a patient five to 10 years along the line it’s hard to see the scars. And if another physician were to see the patient they’d be hard pressed to tell a surgery had even taken place.”

If tissue is best, why don’t doctors do breast transplants? Ochoa says that putting breast tissue back into an area that previously housed breast cancer is a tricky proposition. Not only are transplants risky, and require the patient to take immunosuppressant drugs, there’s the potential that the new breast tissue could simply develop cancer again and have to be removed once more.

When it comes to tissue reconstruction, Ochoa says that the next big step will involve stem cells—immature cells that can, in theory, grow into whatever kind of cells they are guided to. Ochoa says that some researchers are experimenting with using stem cells along with small injections of fat, to try and promote the growth of fatty tissue in the breast area.

Some have suggested using a patient’s stem cells to regrow an entire healthy breast. Not only are researchers far from having that capability, Ochoa points out that there are some reservations about using stem cells that way too. For the same reason doctors are wary of putting new breast tissue back into a body that once fought breast cancer, they worry that stem cells might promote the development of new cancers. Preliminary studies so far suggest that the implanted stem cells don’t usually promote cancer, but researchers want to do more work to be sure.

But rebuilding a breast isn’t just about creating a soft globe of tissue. Most women that Ochoa sees who opt for breast reconstruction, also opt for nipple reconstruction. Just like with breasts, there are a few different nipple-rebuilding methods. Some women go for a small silicone implant beneath the skin. Others have the surgeon use their own tissue, picking up the skin and wrapping it around itself to make a little standing column. Once the faux nipple is healed, a medical tattoo artist (often a nurse) colors it and the areola. (This may or may not be painful—some women develop feeling in their new breasts, while others never do.)

The problem with nipple reconstructions, however, is that they often don’t hold their shape. “Sometimes as soon as a year [after], it’s all completely gone. Other times it lasts for two to three years,” says Laura Bosworth-Bucher, the co-founder and CEO of a company called TeVido, which is trying to develop a way to 3D-print nipples using a patient’s own skin and fat cells. Bosworth-Bucher says that women she talked to didn’t want to go back in for more surgeries every few years, and that surgeons expressed frustration with their inability to predict which patients’ nipples would last, and which wouldn’t.

Bosworth-Bucher admits that printing nipples was not the first thing she thought of when she encountered 3D-printing technology. They spent the first year hoping to apply 3D-printed tissue technology to wounds and burns. But after she realized there was a lot of competition, and that the clinical trials were long and complicated, she started meeting with surgeons to try and think of another way to use the technology. “It was through a brainstorming session with a couple of plastic surgeons, he says, ‘We’re talking about skin, could you work with fat cells?’ And kind of a classic ‘Aha!’ moment, where he says that and we’re like, ‘Well sure, why not?’”

Now, TeVido is focused on developing a 3D-printed nipple, that can be printed not only to size, but with the exact color a woman wants. The technology works a bit like an old inkjet printer—layering cells one on top of another at the micron level to build up frameworks of blood vessels and tissues. Right now, a nipple reconstruction costs somewhere between $3,500 and $4,000, which is the price range they’re hoping their nipples will come in at. The team hopes to get started on clinical trials in two to three years—and because they’re working on something that doesn’t involve an open wound, with an outcome that’s easy to measure (is the nipple there, yes or no?) they hope the trials will move quickly.

Of course, not all women opt for reconstruction, or nipples, or anything of the sort. But when they do, what they want, still, just like Wolfe said back in 1904, is something that provides comfort, appearance, and product quality. And with advances in technology, they’re getting it, and their options are getting safer, longer lasting, and more realistic.