Radiation Modality (Proton/Photon), Timing, and Complication Rates in Patients With Breast Cancer Receiving 2-Stages Expander/Implant Reconstruction

Post-mastectomy radiation therapy after breast reconstruction: from historic dogmas to practical expert agreements based on a large literature review of surgical and radiation therapy considerations

Breast reconstruction (BR) after mastectomy is important to consider for a woman's body image enhancement and psychological well-being. Although post-mastectomy radiation (PMRT) significantly improves the outcome of patients with high-risk breast cancer (BC), PMRT after BR may affect cosmetic outcomes and may compromise the original goal of improving quality of life (QoL). With the lack of practical guidelines, it seems essential to work on a consensus and provide some "expert agreements" to offer patients the best option for PMRT after BR. We report a global "expert agreement" that results from a critical review of the literature on BR and PMRT during the 6th international multidisciplinary breast conference in March 2023.

Predictors for Prolonged TE-to-Implant Exchange During Implant-Based Breast Reconstruction: A Single Institution Experience

BACKGROUND

There is limited evidence regarding the factors causing a prolonged time for tissue expander (TE) exchange into a definitive implant using two-stage implant-based breast reconstruction (IBBR). This study aimed to review our experience with IBBR, focusing on the time for TE-to-implant exchange and determining which factors cause a prolonged time for exchange.

METHODS

A retrospective review was performed to include women undergoing immediate two-stage IBBR with TEs after total mastectomy between January 2011 and May 2021. Reconstructions with irradiated TEs were excluded. Cases that had a prolonged time for TE-to-implant exchange were defined as those undergoing exchange longer than 232 days, which corresponds to the 75th percentile of the overall study group.

RESULTS

We included 442 reconstructions in our analysis. The median age for our series was 51 years and the median body mass index was 26.43-kg/m2. The median time for TE-to-implant exchange was 155 days [IQR, 107-232]. Cases that had a prolonged time for TE-to-implant exchange were defined as those undergoing exchange on postoperative day 232 or afterward. Diabetes (OR 4.05, p = 0.006), neoadjuvant chemotherapy (OR 2.76, p = 0.006), an increased length of stay (OR 1.54, p = 0.013), and a lengthier time to complete outpatient expansions (OR 1.018, p < 0.001) were independently associated with a prolonged time for exchange.

CONCLUSION

As evident from our analysis, the time for exchange is highly heterogeneous among patients. Although several factors affect the timing for TE-to-implant exchange, efforts must be directed to finalize outpatient expansions as soon as possible to expedite the transition into a definitive implant.

LEVEL OF EVIDENCE III

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A Phase II Study Evaluating the Effect of Intensity Modulated Postmastectomy Radiation Therapy on Implant Failure Rates in Breast Cancer Patients With Immediate, 2-Stage Implant Reconstruction With an MRI Imaging Correlative Substudy

PURPOSE

Postmastectomy radiation therapy is a mainstay in the adjuvant treatment of node-positive breast cancer, but it poses risks for women with breast reconstruction. Multibeam intensity-modulated radiation therapy improves dose conformality and homogeneity, potentially reducing complications in breast cancer patients with implant-based reconstruction. To investigate this hypothesis, we conducted a single-arm phase 2 clinical trial of breast cancer patients who underwent mastectomy/axillary dissection and prosthesis-based reconstruction.

METHODS AND MATERIALS

The primary endpoint was the rate of implant failure (IF) within 24 months of permanent implant placement, which would be considered an improvement over historical controls if below 16%. IF was defined as removal leading to a flat chest wall or replacement with another reconstruction. Patients were analyzed in 2 cohorts. Cohort 1 (RT-PI) received radiation therapy to the permanent implant. Cohort 2 (RT-TE) received radiation therapy to the TE. IF rates, adverse events, and quality of life were analyzed. Follow-up/postradiation therapy assessments were compared with the baseline/preradiation therapy assessments at 3 to 10 weeks after exchange surgery. A subgroup underwent serial magnetic resonance imaging (MRI) sessions to explore the association between MRI-detected changes and capsular contracture, a known adverse effect of radiation therapy.

RESULTS

Between June 2014 and March 2017, 119 women were enrolled. Cohort 1 included 45 patients, and cohort 2 had 74 patients. Among 100 evaluable participants, 25 experienced IF during the study period. IF occurred in 8/42 (19%) and 17/58 (29%) in cohorts 1 and 2, respectively. Among the IFs, the majority were due to capsular contracture (13), infection (7), exposure (3), and other reasons (2). Morphologic shape features observed in longitudinal MRI images were associated with the development of Baker grade 3 to 4 contractures.

CONCLUSIONS

The rate of IF in reconstructed breast cancer patients treated with intensity-modulated radiation therapy was similar to, but not improved over, that observed with conventional, 3-dimensional-conformal methods. MRI features show promise for predicting capsular contracture but require validation in larger studies.

Breast Reconstruction Complications After Postmastectomy Proton Radiation Therapy for Breast Cancer

Purpose

Our purpose was to report complications requiring surgical intervention among patients treated with postmastectomy proton radiation therapy (PMPRT) for breast cancer in the setting of breast reconstruction (BR).

Methods and Materials

Patients enrolled on a prospective proton registry who underwent BR with immediate autologous flap, tissue expander (TE), or implant in place during PMPRT (50/50.4 Gy +/- chest wall boost) were eligible. Major reconstruction complication (MRC) was defined as a complication requiring surgical intervention. Absolute reconstruction failure was an MRC requiring surgical removal of BR. A routine revision (RR) was a plastic surgery refining cosmesis of the BR. Kaplan-Meier method was used to assess disease outcomes and MRC. Cox regression was used to assess predictors of MRC.

Results

Seventy-three courses of PMPRT were delivered to 68 women with BR between 2013 and 2021. Median follow-up was 42.1 months. Median age was 47 years. Fifty-six (76.7%) courses used pencil beam scanning PMPRT. Of 73 BR, 29 were flaps (39.7%), 30 implants (41.1%), and 14 TE (19.2%) at time of irradiation. There were 20 (27.4%) RR. There were 9 (12.3%) MRC among 5 implants, 2 flaps, and 2 TE, occurring a median of 29 months from PMPRT start. Three-year freedom from MRC was 86.9%. Three (4.1%) of the MRC were absolute reconstruction failure. Complications leading to MRC included capsular contracture in 5, fat necrosis in 2, and infection in 2. On univariable analysis, BR type, boost, proton technique, age, and smoking status were not associated with MRC, whereas higher body mass index trended toward significance (hazard ratio, 1.07; 95% CI, 0.99-1.16; P = .10).

Conclusions

Patients undergoing PMPRT to BR had a 12.3% incidence of major complications leading to surgical intervention, and total loss of BR was rare. MRC rates were similar among reconstruction types. Minor surgery for RR is common in our practice.

Proton Therapy in Breast Cancer: A Review of Potential Approaches for Patient Selection

Proton radiotherapy may be a compelling technical option for the treatment of breast cancer due to its unique physical property known as the "Bragg peak." This feature offers distinct advantages, promising superior dose conformity within the tumor area and reduced radiation exposure to surrounding healthy tissues, enhancing the potential for better treatment outcomes. However, proton therapy is accompanied by inherent challenges, primarily higher costs and limited accessibility when compared to well-developed photon irradiation. Thus, in clinical practice, it is important for radiation oncologists to carefully select patients before recommendation of proton therapy to ensure the transformation of dosimetric benefits into tangible clinical benefits. Yet, the optimal indications for proton therapy in breast cancer patients remain uncertain. While there is no widely recognized methodology for patient selection, numerous attempts have been made in this direction. In this review, we intended to present an inspiring summarization and discussion about the current practices and exploration on the approaches of this treatment decision-making process in terms of treatment-related side-effects, tumor control, and cost-efficiency, including the normal tissue complication probability (NTCP) model, the tumor control probability (TCP) model, genomic biomarkers, cost-effectiveness analyses (CEAs), and so on. Additionally, we conducted an evaluation of the eligibility criteria in ongoing randomized controlled trials and analyzed their reference value in patient selection. We evaluated the pros and cons of various potential patient selection approaches and proposed possible directions for further optimization and exploration. In summary, while proton therapy holds significant promise in breast cancer treatment, its integration into clinical practice calls for a thoughtful, evidence-driven strategy. By continuously refining the patient selection criteria, we can harness the full potential of proton radiotherapy while ensuring maximum benefit for breast cancer patients.

Technical consideration for breast reconstruction in patients requiring neoadjuvant or adjuvant radiotherapy: a narrative review

Background and Objective

Surgical considerations for breast reconstruction (BR) in patients requiring neoadjuvant radiotherapy (NART) or adjuvant radiotherapy (ART) cannot be understated. The management of irradiated tissue leads surgeons to face several challenges. Therefore, it is essential to comprehensively understand the proper patient selection and preoperative planning to ensure the best outcomes and minimize the risk of complications. This narrative review aims to provide an update and summary of the most important technical considerations every breast surgeon must contemplate reconstructing the irradiated breast.

Methods

The search strategy was performed on January 10th, 2023. The PubMed, Embase, Cochrane Library, and Web of Science databases were queried to capture all publications regarding surgical considerations in BR of patients undergoing NART and ART.

Key Content and Findings

This review shows that the effects of radiotherapy (RT) on BR are still being studied. RT represents an essential factor for overall patient survival, and its use is increasing. However, the range of RT treatments across different cancer centers complicates the creation of a single treatment protocol. BR improves women's quality of life, so finding the proper integration of BR and RT is essential. When deciding on the reconstructive method, there are several factors to consider, such as the patient's body characteristics, tumor stage, RT protocol, and chemotherapy. To achieve the best surgical results and the most satisfied patient, using less aggressive and safer RT methods in the treatment sequence is recommended.

Conclusions

The timing of the radiation will influence the selection of the best reconstructive methods to be employed in the breast cancer patient. However, there is clear evidence of preference for immediate autologous-based BR in cases due to the low rate of complications in the long term. But patient individualization is the key. Therefore, the benefits and risks of immediate versus delayed and autologous versus implant-based reconstruction must be weighed in every single case.

Impact of Varying Chest Wall Target Volume Delineation on Postmastectomy Radiation Therapy Outcomes in Breast Cancer Patients with Implant-Based Reconstruction

BACKGROUND

The target volume for post-mastectomy radiation therapy (PMRT) in breast cancer patients with reconstruction has been a subject of debate. Traditionally, the RT chest wall (CW) volume encompasses the entire implant. For patients with retropectoral implants, the deep lymphatic plexus dorsal part of the implant is no longer considered high risk and can be omitted. This study aimed to assess the radiation dose distribution and treatment outcomes associated with different CW delineation according to ESTRO ACROP guideline for patients who have undergone implant-based reconstruction.

METHODS

We conducted a retrospective review of breast cancer patients who underwent a mastectomy followed by two-stage implant-based breast reconstruction and adjuvant radiation therapy (RT) between 2007 and 2022. The expanders/implants were positioned retropectorally. The chest wall target volumes were categorized into two groups: the prepectoral group, which excluded the deep lymphatic plexus, and the whole expander group.

RESULTS

The study included 26 patients, with 15 in the prepectoral group and 11 in the whole expander group. No significant differences were observed in normal organ exposure between the two groups. There was a trend toward a lower ipsilateral lung mean dose in the prepectoral group (10.2 vs. 11.1 Gy, p = 0.06). Both groups exhibited limited instances of reconstruction failure and local recurrence.

CONCLUSIONS

For patients undergoing two-stage expander/implant retropectoral breast reconstruction and PMRT, our data provided comparable outcomes and normal organ exposure for those omitting the deep lymphatic plexus.

Factors Associated with Reconstruction Failure and Major Complications After Postmastectomy Radiation to a Reconstructed Breast

PURPOSE

Postmastectomy radiation therapy is known to increase risk of complications in the reconstruction setting. We aim to identify the variables associated with reconstruction failure and other major complications.

METHODS AND MATERIALS

A prospectively collected institutional database was queried for patients with up to stage IIIC breast cancer treated from 2000 to 2017, undergoing mastectomy, immediate implant or autologous tissue reconstruction, and radiation to the reconstructed breast within 1 year of surgery. Reconstruction failure was defined as complication requiring surgical revision or implant removal. Additional major complications were defined as any infection, contracture, necrosis, or fibrosis. Covariates of interest included age, body mass index, smoking status, stage, hormone receptor and HER2 status, systemic therapy timing, radiation technique, nodal irradiation, and interval between surgery and start of postmastectomy radiation therapy. Differences in complication rates were assessed with χ² or Fisher exact tests. Competing risk regression was used to estimate hazard ratios; covariates were included one at a time to avoid over adjustment.

RESULTS

A total of 206 reconstructed breasts in 202 patients resulted from our initial query, with 139 treated with intensity-modulated radiation therapy (IMRT) and 67 treated with conventional radiation therapy (CRT). Median follow-up was 45 months (range, 4-210 months); patient cohorts were generally similar. Eight patients were excluded from toxicity analysis for insufficient follow-up (<2 years). Overall, reconstruction failure and major complication rates were significantly lower in the IMRT group. Reconstruction failure rates were 3.0% for IMRT versus 16.4% for CRT (P = .002), and major complication rates were 6.8% for IMRT versus 24.6% for CRT (P < .001). On univariate analysis, CRT was significantly predictive of implant failure (hazard ratio, 5.54; P = .003) and increased complication rates (hazard ratio, 3.83; P = .001). Significance persisted on multivariable analysis. Survival outcomes were similar, with no difference in 2 year overall survival (P = .12) and local recurrence (P = .41).

CONCLUSIONS

Using IMRT may improve reconstruction outcomes over CRT, with significantly lower reconstruction failure and complication rates without compromising local control or survival.

Reconstructive complications and early toxicity in breast cancer patients treated with proton-based postmastectomy radiation therapy

Background

Postmastectomy radiation therapy (PMRT) decreases the risk of locoregional recurrence and increases overall survival rates in patients with high-risk node positive breast cancer. While the number of breast cancer patients treated with proton-based PMRT has increased in recent years, there is limited data on the use of proton therapy in the postmastectomy with reconstruction setting. In this study, we compared acute toxicities and reconstructive complications in patients treated with proton-based and photon-based PMRT.

Methods

A retrospective review of our institutional database was performed to identify breast cancer patients treated with mastectomy with implant or autologous reconstruction followed by PMRT from 2015 to 2020. Baseline clinical, disease, and treatment related factors were compared between the photon-based and proton-based PMRT groups. Early toxicity outcomes and reconstructive complications following PMRT were graded by the treating physician.

Results

A total of 11 patients treated with proton-based PMRT and 26 patients treated with photon-based PMRT were included with a median follow-up of 7.4 months (range, 0.7-33 months). Six patients (55%) in the proton group had a history of breast cancer (3 ipsilateral and 3 contralateral) and received previous RT 38 months ago (median, range 7-85). There was no significant difference in mean PMRT (p = 0.064) and boost dose (p = 0.608) between the two groups. Grade 2 skin toxicity was the most common acute toxicity in both groups (55% and 73% in the proton and photon group, respectively) (p = 0.077). Three patients (27%) in the proton group developed grade 3 skin toxicity. No Grade 4 acute toxicity was reported in either group. Reconstructive complications occurred in 4 patients (36%) in the proton group and 8 patients (31%) in photon group (p = 0.946).

Conclusions

Acute skin toxicity remains the most frequent adverse event in both proton- and photon-based PMRT. In our study, reconstructive complications were not significantly higher in patients treated with proton- versus photon-based PMRT. Longer follow-up is warranted to assess late toxicities.