Journal time!
There was a study a few years ago which showed in the lab that stem cells caused cancers to grow. This is a big issue if you want to graft fat to the breast, as there are naturally occurring stem cells in fat. When in vivo studies were done, they did not show this correlation. So which is correct- does fat grafting cause cancer cells to grow or not?
It is an important distinction, as we like to use fat transfer to the breast to help the aesthetics of breast cancer reconstruction. If you had a lumpectomy and there is residual breast tissue (and hopefully not, but could have some cancer cells remaining), if we graft fat to the breast would we be helping a new cancer grow?
Studies in the lab have been hindered by stem cells lines and other issues in trying to mimic the scenario equal to a woman’s breast who has a history of breast cancer.
This was a study done on mice. They had 40 mice (immunosuppressed) who had estrogen receptor positive tumors placed. They were then injected with either saline or fat and then watched for 2 weeks. The question? Did the mice who had the injection of fat (and the stem cells which come with fat transfer) have bigger tumors? more spread? different histology?
Findings?
The SALINE had higher volume and mass of tumors after injection. There was no difference in histology, and no metastasis were seen. They think the effect was a mass effect- the fat cells caused pressure on the tumor cells, or on the blood supply, which caused the cancer cells to die.
Thoughts?
It is an interesting study, and helps reassure us that in real life injecting fat into the breast isn’t going to increase your risk for a breast cancer. This correlates with past studies done in vivo, which don’t show an increased recurrence or cancer rate in women who have had fat transfer to the breast.
But nice to see.
The authors do state that this still is not a perfect model. Immunocompromised mice may not have the same responses as non immune compromised mice. It is also interesting to think if it was a mass effect of the injection, maybe next time graft something other than saline- try dermis or something else- which would maintain its mass.