But the researchers add strong caveats to that conclusion.
"After breast cancer treatment, the patient has to be followed more carefully," says study researcher Jean Yves Petit, MD, of the European Institute of Oncology in Milan, Italy. A surgeon experienced in the technique must do the surgery, he tells WebMD.
The study is published in Plastic and Reconstructive Surgery.
While the complication rate was low, Petit says it is too soon to prove safety in terms of cancer recurrence. "We cannot provide the definitive proof of the safety of lipofilling in terms of cancer recurrence or distant metastasis," he writes. Longer studies are need, he tells WebMD. His follow-up lasted about a year and a half.
In another recent study, Petit compared women who had lipofilling after breast cancer with comparison women who did not have the procedure and found it safe, although he still concludes that more study is needed. That study is published in the Annals of Oncology.
How Lipofilling Works
In lipofilling, fat is taken by liposuction from one part of the body. It is processed and then injected into the breasts to contour them. The procedure is also used in women without cancer, to improve the appearance of the breasts or enlarge them.
However, in women who have had breast cancer, doctors worry that the injected fat cells may somehow stimulate the growth of any dormant cancer cells or eventually induce new cancer cells.
There is no international agreement on the technique when used after breast cancer treatment, Petit says. In the U.S., for instance, the American Society of Plastic Surgeons Fat Graft Task Force in 2009 concluded that no studies can confirm the oncologic safety of lipofilling in cancer patients.
In the most recent study, Petit and colleagues evaluated 513 women who had 646 lipofilling procedures done from 2000 to 2010. Of the 513 women, 370 had undergone mastectomy. The other 143 had breast-conserving surgery.
Nearly 79% had invasive cancers. The other 21% had earlier stage cancer. The average age was 52.
The women were cared for at three different institutes in Italy and France.
The lipofilling was done, on average, more than three years after the surgery. The average follow-up was more than 19 months.
Overall, Petit found a complication rate lower than 3%. Most common was cell death of some of the injected fat.
During the follow-up, breast cancers were found in 5.6% of patients. When the doctors looked only at the breast that originally had the cancer, breast cancers were found in 2.4%. Recurrence was more common in those who had breast-conserving surgery. The researchers did not find that the injected fat interfered with the ability of the mammograms to detect cancer recurrence.
In the earlier study, Petit tracked 321 women with breast cancer who had surgery between 1997 and 2008. Later, they had lipofilling. He compared those women with two comparison patients each.
After a median follow-up of more than four and a half years, he found that eight in the lipofilling group had a local cancer found and 19 did in the comparison group. That makes the rates comparable, he says.
When he looked just at noninvasive cancer that starts in the breast, he found three cases in the fat-injection group and none in the comparison patients. However, he says, this could be due to some study biases in picking the comparison group.
More Research Needed
The results of the new research "doesn’t show there is a problem yet, but we still need to keep looking [in breast cancer patients]," says Sydney Coleman, MD, a Manhattan plastic surgeon and assistant clinical professor of surgery at New York University Medical Center. He is a pioneer in the technique.
The procedure itself, he says, has very few complications. Women who get the injections for augmentation can typically get a one-cup increase in size, he says.
"We need more studies to really determine the oncological risk," he tells WebMD. "We have so little data on cancer recurrence."
He reviewed the study but was not involved in it. Coleman reports royalties from the Coleman cannula, a device used in the procedure. He is an advisor to Mentor, which makes it.
Kamran Khoobehi, MD, professor of surgery at Louisiana State University in New Orleans, often performs the technique. The study findings should be reassuring, he says, although he agrees more study is needed.
"This study confirms there is no increased risk of local recurrence or systemic recurrence [in women who get the injections vs. those who don't]," he tells WebMD.