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Infection may cause implant-associated ALCL


 

Breast implant

Credit: FDA

Bacterial infection on the surface of textured breast implants may increase the risk of developing breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL), according to research published in Plastic & Reconstructive Surgery.

Previous studies have shown that biofilm infection around breast implants is a major cause of capsular contracture, a painful hardening of the tissue around the implant that can cause physical deformity and pain.

Now, researchers have found that chronic infection around implants can also lead to an activation of the immune system and the patient’s lymphocytes. And long-term stimulation of lymphocytes by this infection may prompt the transformation of these cells into BIA-ALCL.

The infection was shown to be highest around textured breast implants, and this may provide an explanation as to why BIA-ALCL seems to be more common in patients with textured implants.

“Our previous research has shown that, 24 hours after bacteria come into contact with breast implants, textured implants had 72 times the number of bacteria attached to their surface as compared with the smooth implants,” said Anand Deva, MBBS, of Macquarie University in Sydney, Australia.

“This latest study has shown that the textured implants with the highest numbers of bacteria also had the highest number of activated lymphocytes around them. This finding is important and has now become even more relevant since the reporting of BIA-ALCL, as it provides us with a possible biological explanation of how this rare cancer could arise.”

To uncover these findings, Dr Devan and his colleagues first examined implants in pigs. The team inserted 12 textured and 12 smooth implants into submammary pockets in 3 adult pigs.

After a mean of 8.75 months, all of the samples were positive for bacterial biofilm. And there was a significant correlation between bacterial numbers and the grade of capsular contracture (P=0.04).

Lymphocyte numbers were significantly higher on textured implants (P<0.001), with T cells accounting for the majority of the lymphocytic infiltrate.

The researchers then examined implants in humans, collecting 57 capsules from patients with Baker grade 4 capsules over a 4-year period. The team analyzed biofilm and the surrounding lymphocytes.

As in the pigs, all of the capsules were positive for biofilm, and T cells were the predominant lymphocyte (P<0.001).

The researchers also discovered a significant linear correlation between the number of T and B cells and the number of detected bacteria (P<0.001). And there was a significantly higher number of bacteria for polyurethane implants (P<0.005).

These results suggest a possible link between bacterial biofilm and T-cell hyperplasia, a finding that may have implications for BIA-ALCL, the researchers said.

Dr Deva and his colleagues have published a 14-step guide to reduce the risk of breast implant infection, based on evidence of best practice to educate surgeons on how to reduce the risk of bacterial contamination.

A number of clinical studies have applied these principles and successfully reduced the rate of capsular contracture by a factor of 10 in their patients.

“This is a great validation of our research and a demonstration that good science in the laboratory can be translated into real benefits to patients at the bedside,” Dr Deva said.

“Now, with our greater understanding of the importance of preventing infection, we, as surgeons, can reduce the risk of capsular contracture and thereby reduce the risk of lymphocyte activation and possible transformation into BIA-ALCL.”

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