Breast Implants and Radiation

Abstract

One of the most influential factors in the success of breast reconstruction is whether or not radiation therapy has or will be performed. While traditional teaching is that all breasts treated with radiation therapy must be reconstructed with an autologous component, many reconstructive surgeons perform implant-based breast reconstruction without an autologous component and have success doing so. The purpose of this article is to explore the risks, benefits, and nuances of performing implant-based breast reconstruction in the setting of radiation therapy. The authors performed a review of the literature of all topics relevant to performing implant-based reconstruction with radiation therapy.

The oncologic benefit of radiation therapy is indisputable, having been shown to decrease local tumor recurrence and increase overall survival for a variety of malignancies, including breast cancer. ^{1 2 3} Over the past several years, the indications for radiation therapy have been gradually liberalized to include patients with earlier stages of breast cancer. ⁴ Unfortunately, radiation therapy is also well known to compromise the body's ability to heal a wound due to its association with soft-tissue fibrosis and the inhibition of angiogenesis. ^{5 6 7 8} To mitigate many of the deleterious effects radiation has on breast reconstruction, the standard of care is to utilize autologous tissue. A delayed breast reconstruction with autologous tissue is associated with a lower complication rate and greater patient satisfaction compared with an implant reconstruction in women with a history of radiation. ^{9 10 11 12} However, not all women are candidates for autologous reconstruction and others may not desire it despite its apparent advantages. Moreover, with increasing experience with implants, improved technology, and changes in technique (such as the use of acellular dermal matrices [ADMs]), implant-based reconstruction is now the most commonly used method of reconstruction in patients receiving immediate reconstruction followed by postmastectomy radiation therapy. ¹³ There are two main prosthetic breast reconstruction techniques after mastectomy: two-stage expander–implant reconstruction and single-stage direct-to-implant reconstruction. Furthermore, there are other clinical scenarios involving breast implants and radiation that should be considered, such as the use of breast implants for reconstruction in breast-conserving therapy and the treatment of breast cancer in the previously augmented breast. Plastic surgeons who perform breast surgery should be familiar with the latest recommendations related to breast implants and radiation.

Radiation and Prosthetic Breast Reconstruction: The Radiation Oncology Perspective

From the perspective of a radiation oncologist, a key question is whether specific reconstructive approaches allow for optimal coverage of the chest wall and internal mammary nodes, while minimizing doses to the lungs and heart. Several studies have found that radiation can be delivered effectively and safely after prosthetic breast reconstruction. ^{14 15 16 17} However, treatment of the internal mammary nodes does pose a challenge in certain situations, as it is difficult to effectively capture this region in women with a full expander. In this scenario, the expander may require partial deflation to adequately treat the internal mammary nodes without exposing the heart and lungs to an inappropriate dose of radiation. In general, direct-to-implant reconstruction or radiation of the implant after the removal of the expander and implant placement does not compromise radiation delivery because the implant tends to displace slightly laterally when the patient is supine. Prepectoral, subcutaneous breast reconstruction is gradually becoming more popular. Placement of the implant or expander in this plane does effect radiation dose planning, because the pectoral fascia—which is a target of radiation—and the skin and subcutaneous tissues are now separated by several centimeters due to the location of the prosthesis. Therefore, it is very important that the radiation oncologist is aware of the plane of reconstruction so that the necessary adjustments can be made.

Both tissue expanders and breast implants are composed of a silicone shell. The nature of radiation effects on soft tissues has been deeply investigated; however, there are very few studies examining the effects of radiation on the prosthetic device. Ribuffo and colleagues examined the effect of postmastectomy radiation therapy on breast implants, using multiple techniques. ¹⁸ They failed to find any evidence of radiation-induced modifications to silicone on the microscopic level using scanning electron microscopy; there was also no difference in tensile strength, elastic modulus, or elongation at break as measured via tensiometry. Radiation does not appear to affect the mechanical properties or microscopic structure of silicone.

Radiation in the Setting of Two-Stage Expander–Implant Reconstruction

Reconstruction using the two-stage approach is the most common technique in the United States, accounting for 80% of all breast reconstructions. ¹⁹ Radiation therapy is known to increase rates of reoperation, reconstructive failure, capsular contracture ( Fig. 1 ), infection, and total complications in implant-based reconstructions. ^{20 21 22 23} There are many treatment variations regarding radiation therapy and two-stage reconstruction, with no general consensus as to what is most efficacious. Some of the questions that remain include radiation of the expander versus the implant, the optimal period of time to wait between radiation and the next surgery, and the best tissue plane in which to place the device.

Fig. 1.

Anteroposterior view of a patient with Baker grade 3 capsular contracture associated with the patient's left breast tissue expander. The overlying skin is firm and fixed to the underlying expander. The expander is more superiorly positioned on the chest wall and the left inframammary fold is several centimeters higher than the right.

We reviewed several studies looking at two-stage expander–implant reconstruction ( Table 1 ). The infection rate ranged from 0 to 27%. The frequency of Baker grade 3 or 4 capsular contracture varied from 2 to 57.8%; generally a higher rate of capsular contracture was noted with radiation of the implant as opposed to the tissue expander. The incidence of reconstructive failure ranged from 4.8 to 40%; generally a greater rate of failure was observed when the tissue expander was irradiated as opposed to the implant.

Table 1. Studies reporting outcomes after two-stage expander–implant breast reconstruction in the setting of radiation.

Reference	Level of evidence	Patients ( n )	RT to TE or implant	Infection rate	Capsular contracture a	Reconstructive failure	Total complications
Anderson et al 24	III	62	TE	4.80%	–	4.80%	33.30%
Anker et al 25	III	61	TE	7%	2–26%	33.30%	40%
Collier et al 26	III	32	TE	9.40%	–	6.30%	–
Collier et al 26	III	22	Implant	9.10%	–	4.50%	–
Cordeiro et al 27	III	94	TE	–	17%	18%	–
Cordeiro et al 27	III	210	Implant	–	50%	12%	–
Cowen et al 28	II	143	TE	–	32.50%	22.70%	–
Drucker-Zertuche et al 29	III	37	TE	–	21.60%	16.20%	45.90%
Fowble et al 30	III	86	TE	–	–	19.80%	–
Hirsch et al 31	IV	237	TE	–	–	22.40%	–
Ho et al 32	IV	151	Implant	–	21.70%	29%	–
Lentz et al 33	III	34	TE	23.50%	11.80%	20.60%	–
Lentz et al 33	III	22	Implant	18.20%	40.90%	13.60%	–
Lin et al 23	III	51	TE	0%	–	20%	41.20%
Nava et al 34	II	50	TE	–	53.30%	40%	–
Nava et al 34	II	109	Implant	–	57.80%	6.40%	–
Peled et al 35	III	88	TE	–	–	22.70%	–
Santosa et al 36	II	104	TE	6.70%	2.90%	11.50%	30.80%
Santosa et al 36	II	46	Implant	10.90%	2.20%	8.70%	23.90%
Sbitany et al 37	III	113	TE	27%	–	17.70%	–
Spear et al 38	III	56	TE	8.90%	12.50%	21.40%	–
Tallet et al 39	III	47	TE	6%	15%	24%	51%

Abbreviations: RT, radiation therapy; TE, tissue expander.

^aBaker grade 3 or 4.

Cordeiro and colleagues performed a single-surgeon retrospective review of 1,415 breast reconstruction patients. ²⁷ Within this cohort. there were 304 patients who required radiation; 94 patients received radiation to their tissue expander, whereas 210 received radiation to the implant, after exchange. Typically radiation was started 4 weeks following the placement of the implant. The study found a statistically significant increased rate of reconstructive failure in the radiated patients (9.1 vs. 0.5%) as well as a significantly higher rate of Baker grade 3 or 4 capsular contracture (6.9 vs. 0.5%).

Chetta and colleagues utilized an insurance claims database to investigate postoperative morbidity in the reconstruction of the irradiated breast. ⁴⁰ After multivariable logistic regression analysis, they found that an implant-based reconstruction in the setting of radiation had 2 times the odds of having any complication and 11 times the odds of reconstructive failure relative to patients with autologous reconstruction.

The Mastectomy Reconstruction Outcomes Consortium (MROC) study represents the largest and most thorough review of postmastectomy radiation therapy and two-stage implant-based reconstruction. ³⁶ In this study, 150 patients were identified from 11 institutions across North America ( Table 1 ). There were 104 patients who received radiation to their tissue expander (69.3%) compared with 46 who received radiation to their implant (30.7%). After controlling for confounding variables, there were no differences in the incidence of any complications, or complications leading to reconstructive failure between the two groups. Furthermore, there was no difference in complications in women who received radiation to their expander compared with those whose implant was radiated.

Despite the findings of the MROC study, the appropriate sequencing of radiation therapy in relation to expander–implant exchange remains in question. Several studies have examined this ( Table 1 ). Peled and colleagues compared 49 patients who underwent exchange to a permanent implant within 6 months of radiation to 39 patients who underwent exchange at 6 months or greater. ³⁵ Patients who waited 6 months or greater had a statistically significantly lower rate of reconstructive failure (7.7 vs. 22.4%). Similarly, Lentz et al found a lower rate of reconstructive failure in women who waited 4 months or greater between the completion of radiation and exchange (14.3 vs. 25%). In general, a lower complication rate is seen with a larger time interval between the completion of radiation and the next surgery. ³³

Irradiating the patient before or after the exchange procedure represents another variation in sequencing. Cordeiro et al found that patients who received radiation to their tissue expander had a lower rate of capsular contracture (17 vs. 50%) but a higher rate of reconstructive failure (18 vs. 12%) compared with those whose implant was radiated. ²⁷ Lee and Mun conducted a meta-analysis examining the effect of radiating the tissue expander versus the breast implant. They analyzed eight studies involving 899 patients. The risks for reconstructive failure and major complications requiring reoperation were higher in patients who received radiation to their expander; however, the difference was not statistically significant. The group with radiation to the tissue expanders had a significantly lower risk of severe capsular contracture compared with the group with radiation to the breast implant. ⁴¹ In the MROC study, Santosa and colleagues failed to identify any difference in complications or reconstructive failure in women who received radiation to their expander compared with those whose implant was irradiated. ³⁶ Given the controversy regarding the optimal timing of radiation, it is also important to keep in mind that not all patients may be appropriate for receiving radiation after exchange. The incidence of neoadjuvant chemotherapy in the treatment of breast cancer is gradually increasing and this precludes delaying radiation.

Following mastectomy, the tissue expander can be placed in the total submuscular plane, in a dual plane with ADM in the inferior pole, or in the total subcutaneous plane (most commonly also with ADM). The effect radiation has in relation to tissue plane is unknown. Seth et al compared patients who received radiation to expanders in the total submuscular plane to patients who received radiation to expanders placed in the dual plane with ADM. ⁴² Three hundred and ninety-three breasts were reconstructed using the total submuscular technique and 199 utilized dual-plane ADM. After adjusting for confounding variables, there was no difference in complication rates between the dual-plane ADM and submuscular breasts on regression analysis. In contrast, Nahabedian identified a 34.8% complication rate in radiated ADM breast reconstructions compared with an 11.7% complication rate in radiated submuscular breast reconstructions. ⁴³ Capsular contracture is known to occur more frequently in the setting of radiation due to the upregulation of genes related to soft-tissue fibrosis. Spear and colleagues demonstrated a 29.6% rate of capsular contracture in patients receiving radiation compared with 0.7% in nonirradiated patients. ³⁸ There is evidence that ADM may be protective against capsular contracture; however, this beneficial attribute is not as readily observed in the setting of radiation. ^{44 45} Expander placement in the subcutaneous or “prepectoral” plane is gaining in popularity. Proponents advocate that this technique provides an excellent aesthetic result without the negative sequelae of disinserting the pectoralis major muscle. Early experience with the subcutaneous plane in breast reconstruction was associated with higher complication rates; however, improvements in technique and reconstruction technology—such as the use of ADM—have contributed to a reduction in complications. ⁴⁶ Bernini et al and Casella et al considered radiation to be an exclusion criterion for subcutaneous breast reconstruction. ^{47 48} In contrast, Sbitany et al did not identify any increased complication rate in irradiated subcutaneous breast reconstructions, in which the filled expander was irradiated, compared with patients whose expander was placed in the dual plane. ⁴⁹

Aesthetic outcomes and patient-reported quality-of-life outcomes after two-stage expander–implant reconstruction in the irradiated breast demonstrate varied and contradictory findings. This is in part due to multiple different scales and metrics used. More recent studies employ the BREAST-Q, an increasingly widely used, psychometrically validated questionnaire designed to measure patient-reported outcomes after breast reconstruction. Cordeiro et al included surgeon-evaluated aesthetic results as well as BREAST-Q data in his study. ²⁷ Aesthetically, the authors found that patients who were not irradiated had a statistically significantly greater percentage of “very good–excellent” ratings in both unilateral and bilateral reconstructions compared with patients whose tissue expander or implant was irradiated. Similarly, nonirradiated patients reported significantly higher satisfaction, psychosocial well-being, sexual well-being, and physical well-being scores compared with irradiated patients.

Radiation in Direct-to-Implant Reconstruction

Single-stage breast reconstruction is attractive to the patient and the surgeon for a variety of reasons: the reconstruction is theoretically complete in a single operation, there is no need for multiple office visits for expansions, and the pain associated with an implant is typically better tolerated than that of a firm tissue expander. The success of direct-to-implant reconstruction necessitates well-vascularized mastectomy skin flaps, a breast cup size ranging from A to C, and minimal ptosis. It is possible to place the implant in either the dual plane under the pectoralis superiorly and supported inferiorly by an ADM sling or in the subcutaneous plane. ^{47 50 51} A known requirement for postmastectomy radiation therapy is a relative contraindication for single-stage breast reconstruction, regardless of the plane; therefore, there are very few studies commenting on radiation in direct-to-implant reconstruction. Using a two-stage approach is thought to be safer and allows additional opportunities to thwart radiation-related capsular contracture and malposition, by overexpanding or adjunctive techniques performed at the time of the implant exchange. Similar to the findings observed in two-stage reconstruction, radiation in single-stage reconstruction appears to be associated with a higher complication rate. Salzberg and colleagues studied their 13-year experience performing direct-to-implant reconstruction. In their cohort, 100 patients had received radiation therapy. They found that radiation showed a 2.9-fold increased odds for developing capsular contracture. ⁵⁰ Clarke-Pearson et al found that radiation was predictive of capsular contracture and reoperation for revision in single-stage reconstructions. ⁵¹ If the requirement for postmastectomy radiation therapy is known preoperatively or highly suspected, reconstruction should be performed using two stages to optimize aesthetic results and minimize complications.

Breast Implants and Breast Conserving Therapy

Segmental mastectomy followed by radiation therapy can result in significant breast asymmetry. To prevent this result, many plastic surgeons are now asked to perform an oncoplastic reconstruction at the time of extirpative surgery. In large-breasted or ptotic women, this can be achieved with a volume displacement maneuver, typically transferring breast tissue into the defect in the form of a modified mastopexy; a contralateral symmetrizing mastopexy is then performed on the other breast. In small-breasted women or women with minimal ptosis, this technique is not possible and therefore the volume must be replaced as opposed to displaced. This is most commonly done with autologous tissue, either in the form of a latissimus flap or local perforator flap. Historically, breast implants have been avoided in this scenario due to a presumed increased complication rate. ^{52 53 54} However, over the last 20 years, implant technology, surgical technique, and radiation techniques have dramatically improved; the avoidance of breast implants in the setting of breast-conserving therapy may be unnecessary and outdated. Barnea and colleagues performed a cohort study, investigating the outcomes of 21 patients who underwent an oncoplastic breast reconstruction using a combination of local tissue rearrangement and subpectoral breast implant placement. All patients underwent radiation postoperatively. They identified a 23.8% rate of Baker grade 3 or 4 capsular contracture. Fourteen percent underwent reoperation because of capsular contracture and two patients developed infection requiring explantation. Six months after the completion of radiation, 81% of patients were either “very satisfied” or “satisfied” with their result, whereas independent observers felt that most of the patients had a “very good” or “good” surgical outcome. ⁵⁵ Lam et al studied a cohort of patients who underwent breast augmentation after segmental mastectomy and radiation. No devices required removal or revision; 73.9% were rated as having an excellent outcome. Although there is a higher associated capsular contracture rate, breast implants may be used in the setting of oncoplastic reconstruction in women who lack sufficient breast tissue for a volume displacement reconstruction. ⁵⁶

Radiation of the Implant in Previously Augmented Women

Many women who have undergone a cosmetic augmentation mammoplasty may develop breast cancer. Some of these women may not require a mastectomy and may be candidates for a breast-conserving approach, thereby necessitating postoperative radiation therapy. Because of the need for radiation, breast conservation has been associated with a poor cosmetic outcome in the previously augmented breast. However, the data on which this claim is based are outdated. ^{52 53 54} Despite this, most women with a history of breast augmentation, who develop breast cancer, will be treated with a total mastectomy and removal of the breast implant. Victor and colleagues studied the cosmetic outcome of breast-conserving therapy in a cohort of women with previous breast augmentation and found that 71% had “good/excellent” results and a low complication rate. ⁵⁷ More recently, 16 women with previous augmentation who wished to retain their implants were treated with lumpectomy and radiation. Little to no change in cosmesis or pain from baseline was reported. Cosmetic outcomes at last follow-up were judged by patients as excellent/good in 81.2% (13/16), and by physicians as excellent/good in 93.8% (15/16). ⁵⁸ Previous breast augmentation should not be considered a contraindication for breast-conserving therapy in women who are otherwise appropriate candidates from an oncologic perspective.

Adjunctive Maneuvers to Improve Results in the Setting of Radiation

Improving outcomes in the setting of prosthetic reconstruction and radiation therapy is challenging. Several studies have been performed, examining various techniques to minimize complications in the radiated breast. The infection rate following prosthetic breast reconstruction has been consistently demonstrated to be greater in women who have received radiation, oftentimes ranging from 15 to 25%. ^{59 60} Mirzabeigi and colleagues examined the effect of extended trimethoprim/sulfamethoxazole antimicrobial prophylaxis after prosthetic breast reconstruction in irradiated patients, comparing it to patients treated with a cephalosporin. Women treated with trimethoprim/sulfamethoxazole demonstrated an 8% infection rate compared with 35% in women treated with a cephalosporin. After multivariate logistic regression analysis, trimethoprim/sulfamethoxazole remained the only significant factor influencing the infection rate. ⁶¹

In the irradiated reconstructed breast, device exposure can occur because of tissue necrosis, delayed healing, and incisional dehiscence ( Fig. 2 ). Radiated tissues have compromised fibroblast function, increased fibrosis, and decreased microvascular perfusion, all of which contribute to impaired healing. Exchanging a tissue expander for a permanent implant through the mastectomy incision results in a higher rate of incisional dehiscence when compared with performing the exchange through a new inframammary fold incision (15 vs. 1.3%). ²⁰ This is thought to be because the centrally placed mastectomy incision has been treated with a greater amount of radiation compared with the more inferiorly located inframammary fold. Therefore, the use of a counter incision has been suggested as one potential maneuver to minimize incisional dehiscence.

Fig. 2.

Exposed breast implant due to incisional dehiscence of the mastectomy incision in a patient who underwent two-stage tissue expander/breast implant reconstruction with radiation delivered to the tissue expander.

Radiation has been consistently associated with an elevated rate of capsular contracture, likely due to its upregulation of multiple pathways responsible for scar formation and fibrosis. Vitamin E has been proposed to have a beneficial effect on radiation fibrosis through its antioxidant properties and inhibition of TGF-β ₁ . ^{62 63} Similarly, pentoxifylline has been proposed to decrease fibrosis due to its ability to inhibit TNF-α, increase vasodilation, and improve erythrocyte flexibility. ⁶³ Several studies have demonstrated a reduction in radiation-induced fibrosis when vitamin E and pentoxifylline are used concurrently. ^{63 64 65} Although the results are preliminary and further investigation is needed, the use of these readily available medications may help reduce capsular contracture in irradiated prosthetic breast reconstructions.

Many plastic surgeons believe that fat grafting can help ameliorate some of the negative soft-tissue sequelae of radiation. There is basic science evidence that fat grafting can increase skin thickness, decrease fibrosis, and increase vascular density in irradiated skin. ^{66 67} There are several studies that demonstrate an improved aesthetic outcome after fat-grafting irradiated skin, citing improvement in soft-tissue suppleness, pigmentation, fibrosis, and overall aesthetic result. ^{68 69 70} Furthermore, fat grafting has not been shown to increase the risk of breast cancer recurrence. ⁷¹ Fat grafting may help reverse some of the deleterious effects of radiation in implant-based breast reconstruction.

Conclusion

Autologous reconstruction remains the preferred method of reconstructing the irradiated breast. Despite this, the majority of women in the United States requiring postmastectomy radiation will undergo reconstruction with some combination of tissue expanders and implants. If the woman who requires postmastectomy radiation is not a candidate for—or does not desire—an autologous reconstruction, the safest and most studied variety of breast reconstruction is two-stage expander–implant reconstruction. It remains to be seen whether it is best to irradiate the expander or the implant, but it has been shown that there are fewer complications when the next surgery is no sooner than 4 to 6 months following the completion of radiation. There is growing evidence regarding the safety and efficacy of single-stage reconstruction in the setting of radiation as well as radiation in prepectoral subcutaneous prosthetic breast reconstruction. The use of breast implants in breast-conserving therapy reconstruction is generally avoided; however, the evidence for doing so is lacking. There are many adjunctive techniques to minimize radiation-related complications in prosthetic breast reconstruction, such as prolonged antibiotic prophylaxis, the use of a counter incision during the exchange surgery, and fat grafting.

Funding Statement

Funding The authors received no financial support for this article.