The question that one can logically ask oneself is: Why have fatty transfers in the breast been subjected to such a controversy?
In fact, it was common sense to consider the transfer of the patient’s own tissues in the breast in a natural, ecological and safe approach, avoiding the addition of artificial products that could bring their own problems (see the Problems of prostheses and their safety report of the ANSM). In addition, the fat transfer is an old technique, as it was used since 1912 by Hollander in a manner relatively close to that which we use today. This technique was more or less abandoned over the years probably due to infections (at the beginning of the last century operating conditions did not benefit from the strict asepsis that we have today), with a rediscovery of its use in the early 80s, following the Illouz’s work on liposuction. Coleman’s work during the 1990s also confirmed the possibility of performing good fat grafts at the cost of a precise and methodical protocol. This work confirmed other data from the literature, such as Bircoll’s, who proposed breast fat transfer with an article published in 1987 in the Plastic and Reconstructive Surgery Journal. This article had sparked an important controversy at that time; some blaming the possibility of giving images that can mask the screening for a possible breast cancer. As a result of this controversy, the American Society of Plastic Surgery (ASPRS) had recommended to avoid fat transfer in the breasts. This recommendation was made without any scientific argument, solely on the basis of the members of the committee opinion. This recommendation, however, had the effect of stopping all research and evaluation work on this subject, which was then heavily taboo.
In 1998 we developed, within the Plastic Surgery team of the Léon Bérard Center in Lyon, a research thema to evaluate the possibilities of using breast fat transfer, called breast lipomodelling, in order to start on a new scientific basis, and not bear the weight of the old taboo. This evaluation work permitted the intervention to be tuned to allow safe transfers of large volume of fat, and to show that fat transfers, if performed satisfactorily, did not interfere with breast imaging, whether in mammography, ultrasound, or MRI. Any images appearing after fat transfer are easily recognizable as areas of cytosteatonecrosis, while other fat areas were perfectly radio-transparent and did not interfere with breast imaging. This work has progressively helped to lift the taboo and broaden the indications of fat transfer in the plastic and reconstructive breast surgery.
But the critics of this technique (with what underlying motivations?) did not say their last word. As a result of our work, no longer able to directly accuse the radiological impact of lipomodeling and fat transfer in the breast, they have launched a controversy over a possible oncogenecity of fat in the breast, and some have even launched an extremely controversial debate and not scientifically based. In 2007 the French Society of Plastic Reconstructive and Aesthetic Surgery was the witness of these not courteous polemics, during a round table that we had organized with Dr. Gerard Flageul on this subject, and which are still in the memories of all the members that participated that day.
The first questions we can ask ourselves: why does this subject give rise to such controversy and why are discussions so lively on this subject, with as little discernment and scientific reasoning?
There are probably psychological and subjective factors. In our Scientific Societies of Plastic Surgery, the breast has always been the subject of much passion, and the elders of our Society are willing to remember of lively discussions on the different techniques of mammoplasty, some being close to fight to defend the preponderance of their technical choices! On the other hand, fat represents in the collective unconscious a negative element, corresponding to the mental shortcut: “I do not like fat persons so I do not like fat”. This mental shortcut mixes very different data: healthy fat (which is an element of energy reserve and stem cell reserves) that contributes to the good health of the individual, with the fat of obesity that corresponds to a fat in excess, which is a disease characterized by excess sick fat (abnormal pro-inflammatory fat likely to favour various diseases such as diabetes, cancer and cardiovascular diseases). Work on stem cells of fat origin shows that the fat is rich in stem cells, and is probably one of the main repair systems of the body. On the other hand, fat in obesity is really noxious and constitutes in this situation a carcinogenic element for the breast, probably by general endocrine effect, and not local. Indeed, the factors that lead to obesity are potent carcinogens for the breasts: either the diet rich in carbohydrate and saturated lipids or lack of physical activity. On the other hand, the peripheral fat of the obese is a diseased fat which then behaves like an endocrine organ transforming the adrenal hormones into estrogen (with a hormone replacement therapy-like action), and also causes hyperinsulinism, which is also a strong carcinogenic factor.
On the other hand, the fat tissue is a tissue rich in growth factors and it is easy, in the framework of poorly designed experimental work, to say whatever you want based on these experimental works. Indeed, if we transfer cancer cells with fat, they grow faster, cancer cells using fat as an element of growth; in the same way, the cancerous cells develop more rapidly when the nutritive elements necessary for cell development are added in culture. Under normal conditions, breast cancer develops in the fibrous part of the breast (in the stroma), then it invades the fatty peripheral tissue, which it colonizes and influences by cellular messages partly clarified currently. What made some people, who had only partially understood the scope of this work on the modes of tumor development of breast cancer (and not on breast carcinogenesis) say that fat transfer could possibly potentially increase the risk of breast cancer. Our work on more than 3,000 personal interventions (6000 in the team, from 1998 to 2017) showed exactly the opposite, with a decrease in the risk of new cancer, especially in the sequelae of conservative treatment, allowing us to ask the question of a probable protective role of the transferred fat. Moreover, the fatty tissue is a tissue of important cellular wealth, and one can influence the experimental research in the sense that one wants, without giving a particular value to a possible application to the clinical repercussion. The crucial point is really the clinical safety.
The fat, in the normal breast, can on the other hand be considered of positive effect with a probable anti-cancer action. In fact, the fatty breast, of the same age and of the same personal and familial antecedent, gives less cancer than the dense and fibrous breast. This is found in many radiology studies that define breast hyperdensity as an independent risk factor for breast cancer. These findings are known for a long time and it is enough to work in pathology during macroscopy; the pathologist seeks cancer in fibrous area, and not in greasy area. Breast cancer is born in the epithelial tissue and needs stroma (connective tissue) to develop; macroscopy allows to observe the stromal areas, and to study them preferentially under the microscope in search of a cancer.
The greasy breast facilitates the early diagnosis of breast cancer since in mammography the cancerous areas appear as opaque in contrast to the clear fatty areas. The clearer the breast is, the easier the diagnosis of breast cancer is, and this is well known to all radiologists and those who regularly watch mammograms. Other arguments allow to consider an anti-cancer action of the fat. Indeed the contribution of stem cells and progenitors, would restore or maintain breast homeostasis, with its ability to repair breast tissue. In addition, fat transfer has an anti-inflammatory effect (this is found daily in clinical practice, in inflammatory pathology or in fat transfers around prosthetic capsules). Inflammation is involved in the development of cancer; the anti-inflammatory effect of fat could have anti-cancerous involvement. Finally, fat transfers, bringing angiogenic progenitors, could regulate and block abnormal angiogenesis, which is an element currently well known to the development of cancers (see the founding works of Folkman, also criticized at the beginning of the presentation of these works, and now recognized as a pioneer having opened a new therapeutic way).
Finally, contrary elements appear in the fundamental literature, and it must be known that much work is being done to understand how obesity increases the risk of cancer, including breast cancer. This is about the big ambiguity between obesity and fat. This ambiguity, misunderstood by some, could explain the discordance of the works in the literature. In particular, many works do not speak of the origin of the fat, which is used during the research; however, most of the time it is fat from obese patients or overweight people coming for cosmetic liposuction (a convenient way for researchers to dispose of human fat). Now, the diseased fat is well known to be of negative effect for human health.
In practice, the review of the literature in medical books clearly shows that the use of fat in a reasoned way is a technique that can be used in good conditions and safely. All the international books of Plastic Surgery published during the last 10 years are without exception in favour of a reasoned use of the fat transfers at the level of the breast plastic surgery (Books: Bostwick, Coleman, Spear, Nahai, Hall-Findlay , Fisher, Jones) and also national treatises with the book on Breast Cancer Surgery at Editions Masson, and also the article in the medical-surgical encyclopedia of Plastic Surgery.
The rare hostile publications, or simply calling for caution, are the work of teams paradoxically using this technique in the most risky cases of oncology, that is to say the sequelae of conservative treatment. This is a paradox that needs to be clarified. From our point of view, it seems more to be a political problem (scientific delay taken by some teams on this subject, competition between teams aiming at a certain leadership in plastic surgery of the breast, rivalries between people, people who do not take into account the immense contribution of this technique to the quality of the results and the quality of life of the patients, the need to become notorious without bringing a real scientific contribution) than of a scientific problem (in the meaning of scientific truth ). To corroborate this impression, we have seen several times patients who had benefited from fat transfers in the breast, procedures done by practitioners who had attacked us at the same time on this subject, in a frontal manner and not courteous during scientific communications of the SOFCPRE (French Plastic Reconstructive and Aesthetic Surgery Society).
Some are seeking to gain notoriety, not by their talent, their creativity, or the richness of their work, but only by interventions in congresses: critical, alarmist, unscientific, and not courteous. These are, it seems to me, examples not to follow. Indeed, if these teams really thought that the fat could have a carcinogenic effect, it would be really surprising, even unhealthy to propose this technique in the most risky situations of coincidence with breast cancer, as the sequelae of conservative treatment. Over the years, the scientific community will be able to judge the intellectual honesty of these people, who will come naturally and surely to this technique (most of them are now coming back to the old term of lipofilling, or the term autograft of adipose tissue), because it is safe, if it is well done, and it gives results unexpected with the other techniques. Furthermore, some surgeons who attack me in congresses, are saying now in medias they are developed this new approach!
To try to move constructively forward and finally lift get rid of this controversy artificially maintained, these are the elements that can be put forward to progress on the subject of the protective nature of the fat compared to cancer, or on a possible onco- genecity:
- The experimental arguments are not very helpful. Indeed, if experimental studies are essential to progress in the interpretation of cellular phenomena, their interpretation is tricky because we can easily introduce a bias in a study (as has been pointed out, if we transfer sick fat, it does not have the same characteristics as the healthy fat of an individual) and the scientific value of the work can be considerably distorted. On the other hand it is difficult to develop a model that restores the transfer of fat tissue in the breast. To this date, there is no model for reconstituting the fat transfer in the breast. Co-culture and co-transfer studies are not good models. They can provide essential information about the interaction of the cancer cell with its environment. This is an exciting topic whose theme is tumour progression (this is a very interesting subject, but different from the one we are interested in here because there is no clinical situation where we transfer fat cells at the same time as cancer cells). On the other hand most of the fundamental studies are inspired by the strong association between obesity and cancer, with the secretion of pro-cancerous cytokines by the sick adipocyte of the obese. This is also a very interesting subject on the oncogenicity of obesity, but which does not correspond to the topic of oncogenicity of normal fat transferred to the breast.
- Ultimately, the answer to this question can only come from clinical arguments. There are currently many studies that are all reassuring and have not shown an increased risk of recurrence or new cancer. If we want to go further, there should be prospective comparative studies, which are very difficult to carry out because the supposed influence is very small, therefore studies with very large number of subjects and long-term follow-up are needed, though difficult to consider.
- Studies in imaging of fat transferred breast, native or preserved, did not show any particular surveillance problem. It is currently accepted amongst expert breast radiologists that lipomodelling does not pose a differential diagnosis problem with breast cancer and does not hinder breast cancer screening (see Congress “Breast Imaging and Plastic Surgery”). Regarding imaging: yes, the lipomodelling of the breast, or fat transfer in the breast, causes a modification; no, these changes are not suspect and do not pose a diagnostic problem for radiologists specialized in breast imaging. It is important, however, to keep in mind the modern diagnostic attitude: facing any suspicious image of the breast, one must carry out a microbiopsy to avoid passing a coincidence between a possible cancer and a lipomodelling.
- Regarding recurrence after cancer. Given the large number of subjects already operated (6000 interventions in our team in Lyon from 1998 to 2017, thousands of cases worldwide), if the incidence of tumour recurrence was high after lipomodelling, available retrospective studies should be bringing the results in this direction, which is not the case. Finally, if one wants to be scientific, one must ask the question between the difference to transfer a fatty flap (Latissimus dorsi flap without prosthesis, or TRAM, or DIEP), and a transfer of fat tissue by lipomodeling. It is in all cases a fat transfer (either in the form of graft or vascularized flap) in the old bed of a tumour (breast reconstruction or sequelae of conservative treatment). For these flap techniques, there is currently significant decline and large numbers, and again there has been no increase in the risk of local recurrence by tissue transfer.
In practice, clinical arguments are therefore paramount to confirm the safety of breast fat transfers. We must continue the radiological work confirming that the lipomodeling does not interfere with the radiological monitoring of the breasts, and also allow the scientific dissemination of radiological aspects after lipomodelling and fat transfer (See “Breast Imaging and Plastic Surgery” Congress, which we organize every 2 years in Lyon, for radiologists specialized in breast imaging). It is necessary to continue the follow-up of patients who underwent surgery, with different clinical situations, be it breast reconstruction after mastectomy, sequelae of conservative treatment or lipomodelling in the native breasts for cosmetic purposes or breast repair surgery. As part of a cautious attitude, it is necessary to pursue a reinforced attitude of safety with a preoperative assessment and a strict follow-up, in order to accumulate the data within the framework of a reinforced and cautious security, and to be able to offer this formidable technique to our patients in good conditions of safety and confirm the probable anti-cancer effect of Lipomodelling.