Safety of radiotherapy in patients undergoing breast reconstruction based on patient-reported outcomes: a multicenter collaborative study.

Background. One of the causes of complications in breast cancer patients after immediate breast reconstruction (IBR) is postmastectomy radiation therapy (PMRT).Aim. Retrospective analysis of the results of IBR, and evaluating the effect of PMRT on the frequency and type of complications.Materials and methods. Between 2015 and 2021, 798 patients underwent IBR with tissue expander or implant in N.N. Petrov National Medical Research Center of Oncology, Ministry of Health of Russia. PMRT was performed in 375 patients (group 1). The remaining 423 patients did not receive PMRT (group 2). Complications, including reconstructive failure (RF), Baker grade III/IV capsular contracture (CC), were recorded and analyzed.Results. Finally, cosmetic result analyzed in 521 patients. In 281 patients of PMRT group (group 1) IBR with expander or implant were performed in 144 and 137 cases, respectively. In the 240 patients without PMRT (group 2), IBR with expander was performed in 81 patients, with implant – in 159 cases. Pooled analysis revealed that overall rate of complications in the PMRT group was 33.8 % (in 95 of 281 patients), in non-irradiation patients – 22.9 % (in 55 of 240 patients), p <0.01. In group 1, RF were recorded in 67 (23.8 %) patients, in group 2 – in 44 (18.3 %) patients, p >0.05. CC in group 1 were detected in 28 (10 %) patients, in group 2 in 11 (4.6 %) patients, p <0.05. In patients with permanent implants RF were detected in 21 (14.6 %) of irradiation patients and in 22 (13.8 %) non-irradiation patients (p >0.2). On the contrary, CC were mentioned in 22 (16.1 %) of irradiated patient and in 8 (5 %) patients that didn’t receive PMRT, p <0.005. After reconstruction with expander RF were diagnosed in 46 (31.9 %) patients after PMRT and in 22 (27.2 %) non-irradiation patients, p >0.2. CC were observed in 6 (4.2 %) patients from PMRT group and in 3 (3.7 %) patients treated without PMRT, p >0.2.Conclusion. PMRT in patients after IBR with simultaneous installation of a permanent implant is characterized by a decrease in the incidence of RF, but an increase in the incidence of CC.

574 Background: Postmastectomy radiotherapy (PMRT) is the standard treatment for improving the prognosis of patients with high-risk breast cancer. Expanded indications for breast reconstruction (BR) will likely increase the number of patients undergoing BR who require PMRT, but combining BR with PMRT raises concerns about complications and aesthetics. Evaluating the impact of PMRT on the health-related quality of life (HR-QOL) in Japanese patients is essential for shared decision-making (SDM). This study assessed differences in postoperative HR-QOL and complications between patients who underwent BR with or without PMRT. Methods: We conducted a multicenter cross-sectional study using a questionnaire survey of patients with primary breast cancer who underwent BR between January 2008 and December 2022 at participating institutions, which was approved by the respective institutional review boards. We used the Japanese version of the BREAST-Q questionnaire and questions on patient backgrounds. Results: We included 1078 patients with primary breast cancer. The questionnaire response rate was 77.0% (830/1078). The non-PMRT and PMRT groups comprised 616 and 214 patients, respectively. The PMRT group had higher rates of axillary lymph node dissection (11.7% vs. 52.4%; P<0.001), adjuvant hormonal therapy (67.2% vs. 90.6%; P<0.001), and perioperative chemotherapy (31.8% vs. 84.0%; P<0.001) than the non-PMRT group. Moreover, the overall complication rate (45.3% vs. 76.2%, P<0.001) and the rates of dermatitis (9.9 vs. 48.1%; P < 0.001), skin necrosis (2.9 vs. 9.8%; P<0.001), breast asymmetry (17.0% vs. 24.3%; P=0.002), capsular contracture (4.9 vs. 16.4%; P<0.001), and lymphedema of the upper limb (1.1% vs. 7.5%; P<0.001) were higher in the PMRT group. Multivariate analysis revealed PMRT as an independent risk factor for dermatitis, skin necrosis, and capsular contracture. In the BREAST-Q assessment, the PMRT group showed lower satisfaction with the breast (55 vs. 49; P<0.001), and with physical (85 vs. 76; P<0.001), psychosocial (55 vs. 49; P<0.001), and sexual well-being (36 vs. 34; P=0.021) than the non-PMRT group. Multiple regression analysis revealed PMRT as an independent factor associated with low BREAST-Q scores for breast satisfaction and physical and psychosocial well-being in patients with BR. Conclusions: This is the first large-scale, multi-institutional study to use patient-reported outcomes to assess the effects of PMRT on HR-QOL in Japanese patients with breast cancer who underwent BR. PMRT was associated with an increased risk of complications and decreased HR-QOL in patients with BR. Of note, these findings do not negate the role of PMRT in patients undergoing BR, but highlight the importance of SDM based on realistic HR-QOL expectations after breast reconstruction surgery with PMRT.

Minimal impact of postmastectomy radiation therapy on locoregional recurrence for breast cancer patients with 1 to 3 positive lymph nodes in the modern treatment era

Post-mastectomy radiation therapy (PMRT) is essential for reducing recurrence in patients with high-risk breast cancer but may negatively impact breast reconstruction outcomes. The impacts of PMRT on breast satisfaction and health-related quality of life (HR-QOL) remain unclear, particularly in Japanese patients. We evaluated the impact of PMRT on breast satisfaction and HR-QOL using BREAST-Q. A multicenter, cross-sectional study was conducted at 10 institutions in Japan. Patients who underwent breast reconstruction with or without PMRT were surveyed using the Japanese version of the BREAST-Q. Endpoints included breast satisfaction and HR-QOL domains (physical, psychosocial, and sexual well-being). Multivariate analysis was performed to identify factors influencing these outcomes. Overall, 1078 patients with primary breast cancer who underwent breast reconstruction were included in this study, with a questionnaire response rate of 77.0% (830/1,078). Data from 830 patients were analyzed (PMRT group: 214, non-PMRT group: 616). The PMRT group had significantly lower breast satisfaction (50.7 vs. 57.5, P < 0.001), physical well-being (70.2 vs. 82.4, P < 0.001), and psychosocial well-being (51.2 vs. 56.4, P < 0.001). There was no significant difference in sexual well-being. PMRT was a predictor of reduced breast satisfaction, physical well-being, and psychosocial well-being. PMRT was associated with decreased breast satisfaction and HR-QOL in patients with reconstructed breasts. Patients should be given comprehensive information regarding the potential impacts of PMRT on breast satisfaction and HR-QOL. Shared decision-making based on realistic preoperative expectations is critical for optimal patient outcomes and satisfaction with treatment modalities.

Biologically Informed Decision-Making for PMRT in pT3N0M0 Luminal Breast Cancers (Protocol MF22-02): International Multicenter Real-World Data.

Background: In current guidelines, there is no definite recommendation regarding postmastectomy radiation therapy (PMRT) in patients with luminal pT3N0M0 breast cancer (BC). The goal of this study is to determine whether PMRT could be safely omitted for a specific subgroup of those patients. Methods and Materials: There were 202 women from 16 centers with pT3N0M0 hormone receptor (HR) positive, Her2 neu (-) BC who underwent mastectomy, were analyzed retrospectively. None of the patients received neoadjuvant chemotherapy. Three patients were excluded because of positive surgical margins. The patients were divided into two groups, PMRT (+) (n=130) and PMRT (-) (n=69). Groups were compared in terms of overall survival, loco-regional recurrence rate, and distant metastases regarding Magee score (MS) (&amp;lt; 18 are considered low risk) (https://path.upmc.edu/onlineTools/mageeequations.html), menopausal status, axillary surgery, pathology, lymphovascular invasion (LVI), adjuvant chemotherapy, and adjuvant endocrine therapy. Results: The majority of the patients had invasive ductal carcinoma (49%, n=98). There was no significant difference regarding tumor size, axillary surgery, and adjuvant endocrine therapy between the two groups (p=0.82, p=0.28, p=0.12, respectively). LVI was 49% (n=98) and it was greater in PMRT (+) group (25% vs. 10%; p=0.01). PMRT (+) patients received more chemotherap(66% vs. 30%; p&amp;lt; 0.001), had more grade 3 tumors (28% vs. 9%, p=0.005), and more premenopausal (49% vs. 22%; p=0.0001). At a median follow-up of 51.3 months for the PMRT (-) group and 65.9 months for the PMRT (+) group (p=0.041), 9% (n=6) of patients from the PMRT (-) group and 2% (n=3) from the PMRT (+) group developed locoregional recurrence (LRR) (p=0.047). There was no difference in local recurrence (1% in PMRT (-) group vs. 2% in PMRT (+); p=0.7) and distant recurrence (7% in PMRT (-) group vs. 3% in PMRT (+); p=0.16) between patients who received PMRT and not had PMRT. Further comparison of the LRR in the PMRT (-) and PMRT (+) groups in patients with an MS &amp;lt; 18 did not show a significant difference (3% vs. 4%; p=0.64). However, among patients with a Magee score ≥18, the PMRT (-) group had a higher LRR rate compared to the PMRT (+) group (11% vs. 2%; p=0.01). In patients with an MS≥18, the administration of PMRT correlates with statistically significantly better LRR-free survival (HR 0.19; 95%CI 0.05 – 0.79; p=0.02). Conclusions: Our findings imply that when considering PMRT for BC with pT3N0M0, HR (+), and Her2 neu (-), clinicians can benefit from a combination of pathological risk factors and recurrence prediction models. Patients with MS&amp;lt; 18 receiving PMRT or not appear to experience a comparable rate of recurrence. Citation Format: Atilla Soran, Caleb King, Parul N. Barry, Rohit Bhargava, Hasan Karanlik, Melis Gultekin, Ferah Yiıdız, Aykut Soyder, Berk Goktepe, Kazim Senol, Caglar Guzel, Ebru Sen Oran, Levent Yeniay, Ahmet Dağ, Selman Emiroglu, Didem Can Trabulus, Alper Coskun, Neslihan Cabioglu, Hagigat Veliyeva, N. Zafer Utkan, Berkay Demirors, Efe Sezgin, John A. Vargo. PMRT Decision with low prediction of genomic test score in pT3N0M0 luminal breast cancer: Protocol MF22-02: International multicenter real-world data [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-22-04.

Aims: The National Mastectomy and Breast Reconstruction Audit report (NMBRA, 2011)1 revealed that immediate implant-based breast reconstruction (IIBR) was the most common type of primary reconstruction performed in the UK (37%). The main reason given by clinicians for not offering immediate breast reconstruction was the need for adjuvant radiotherapy. Post-mastectomy radiotherapy (PMRT) decreases the rate of local recurrence as well as increase the long-term survival in patients who demonstrate intermediate to high-risk features2,3 but has been shown to increase the risk of implant complications in IIBR by up to 24% (Berry et al, 2010)4. Cordeiro et al (2004)5 showed the incidence of capsular contracture was 28% higher in the PMRT group compared with non-irradiated patients. Most patients in the UK receive hypofractionated PMRT of 40.05Gy in 15 fractions over 3 weeks based on the UK Standardisation of Breast Radiotherapy (START) trial6, which demonstrated that hypofractionated PMRT is as safe and effective as the conventional PMRT of 50Gy in 25 fractions over 5 weeks. The aim of this study was to determine whether the conventional PMRT of 50Gy in 25 fractions over 5 weeks (2Gy per fraction) was associated with a reduced risk of implant complications in patients undergoing mastectomy with IIBR compared with hypofractionated PMRT regiment of 40.05Gy in 15 fractions over 3 weeks (2.67Gy per fraction). Methods: A single centre retrospective review of data on patients who underwent IIBR followed by PMRT between September 2012 and May 2017 was conducted. Radiotherapy-related complications (surgical site infection, contracture, implant rupture or leakage, wound breakdown) were compared between the two groups of patients receiving conventional and hypofractionated PMRT. Results: Fifty-nine patients underwent IIBR followed by PMRT. Twenty-six patients received hypofractionated PMRT and thirty-three patients received conventional PMRT. Radiotherapy-related complications occurred in 62% of patients in the hypofractionated PMRT group compared with 45% in the conventional PMRT group (p = 0.30). The incidence of capsular contracture (31% in vs. 21%, p = 0.55) and wound breakdown (23% vs. 15%, p = 0.51) was higher in the hypofractionated PMRT group, but surgical site infection (SSI) was more common in the conventional group (4% vs. 6%, p = 1.00). Discussion: Possible confounding factors (BMI, smoking status, and adjuvant chemotherapy) were not analysed due to the small sample size and limitations of the retrospective nature of this study. However, our overall rate of SSI is low in comparison with national data from the NMBRA (2011), which states the SSI rate of 25% in patients who underwent breast reconstruction surgery. Conclusions: This study suggests that the rate of radiotherapy-related complications is lower in patients treated with conventional PMRT compared with hypofractionated PMRT, however the sample size is too small to demonstrate statistical significance. Further research is required to evaluate the effectiveness of conventional PMRT as an option to facilitate immediate implant-based reconstruction following mastectomy. Citation Format: Chaichanavichkij P, Arun KS, Conibear J, Ullah MZ. Post-mastectomy radiotherapy following immediate implant based reconstruction: A possible solution to a reconstructive challenge [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-16-10.

The number of patients undergoing mastectomy and immediate breast reconstruction with tissue expanders followed by post-mastectomy radiotherapy (PMRT) is exponentially increasing. To reduce the rate of complications, in 2011, the senior author of this manuscript described the use of protective lipofilling in patients undergoing unplanned PMRT to the expander with a specific protocol aiming to decrease the rate of complications. A study was performed to evaluate the thickness of the breast irradiated tissue to create a standard pattern of "protective" lipofilling infiltration on limited key areas that could re-establish a thickness similar to non-radiotreated tissues. We studied 15 patients who had modified radical mastectomy (MRM) with immediate breast reconstruction with tissue expanders and PMRT (Group 1) before expansion (Time1), before PMRT (Time2), after PMRT (Time3), 3months after "protective" lipofilling (Time4), and 6months after "protective" lipofilling (Time5). As a control group, we studied 15 patients who had MRM and immediate breast reconstruction with tissue expanders that would not undergo PMRT (Group 2) at the same time points of GROUP 1 (Time1,2,3). Tissue thickness was studied in specific areas using ultrasounds (US) and magnetic resonance imaging (MRI). US and MRI measurements obtained 6weeks after PMRT and 3months after lipofilling showed an initial decrease and then an average increase in tissue thickness reaching values even higher than the non-radiotreated control group. This preliminary report shows how a one-step "fat belt" surgical pattern of lipofilling delivered to central "selected" areas of the breast can achieve adequate tissue thickness in patients who underwent breast reconstruction with PMRT reaching a thickness similar (and in most cases higher) to non-radiotreated tissues. Further follow-up studies are needed to analyze long-term complications of tissue thinning such as ulceration and implant exposure, in comparison with the "fat capsule" pattern. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Surgical and patient-reported outcomes in an Asian female population with or without adjuvant radiotherapy after immediate free perforator flap breast reconstruction: A retrospective review

Background: The effectiveness of postmastectomy radiation therapy (PMRT) in patients with pT1-2 and 1-3 lymph node metastases remains controversial in the current clinical practice. Patients and Methods: Using data from the Japanese National Clinical Database (NCD) between 2004 and 2012, we evaluated the association of PMRT with recurrence and breast cancer mortality. Patients who underwent mastectomy and axillary node dissection and were diagnosed as pT1-2 with 1-3 node metastases were enrolled. Patients who received presurgical treatment were excluded. We compared clinicopathological factors and prognosis between patients with PMRT (PMRT group) and without PMRT (No-PMRT group). The primary endpoint was the locoregional recurrence (LRR) rate. We also assessed the impact of PNRT according to the number of node metastasis. We considered death as a competing event.Results: Among 8,914 enrolled patients, PMRT group included 492 patients (5.5%), and No-PMRT group did 8,422 patients (94.5%). Patients of PMRT group were younger, had a larger tumor and more node metastases than patients of No-PMRT group. There is no difference in breast cancer subtype between two groups. A median observation time was 6.3 years (arnge 5.0- 9.7 years). There was no significant difference between PMRT group and No-PMRT group in LRR rate (4.0% v.s. 5.0%, P=0.61), any recurrence rate (13.8% v.s. 11.8%, P=0.23), and breast cancer mortality rate (6.0% v.s. 4.3%, P=0.08) at 5 years. Multivariate analysis revealed no significant association between PMRT and LRR while LRR is significantly associated with tumor size larger than 2cm (hazard ratio [HR] 1.48, 95%confidence interval [CI] 1.21-1.82 in 2.1-3.5cm, HR 1.97, 95%CI 1.53-2.53 in 3.6-5.0cm) 2 (HR1.25 95%CI 1.02-1.52) or 3 node metastases (HR 1.40. 95%CI 1.10-1.79), triple-negative subtype (HR 1.64, 95%CI 1.21-2.23). According to the number of node metastasis, LRR in PMRT group was significantly lower than that of No-PMRT group among patients with 3 node metastases (2.6% v.s. 7.0%, P=0.03) while there was no significant difference between two groups among patients with 1 or 2 node metastases. In multivariate analysis, HR was relatively lower in patients with 3 node metastases (HR 0.37, 95%CI 0.11 -1.19) comparing to the patients with 1 (HR 0.97, 95%CI 0.53- 1.77) or 2 node metastases (HR 1.06, 95%CI 0.53-2.09). Tumor size was significantly associated with LRR in patients with 1 (HR 1.51, 95%CI 1.13- 2.02) or 2 node metastases (HR 1.45, 95%CI 1.02-2.07). Chemotherapy was significantly associated with LRR among the patients with 2 (HR 0.57, 95%CI 0.40-0.82) or 3 node metastases (HR 0.4, 95%CI 0.25-0.65).Conclusions: Among the patients with T1-2 and 1-3 node metastases, PMRT was not associated with a reduced risk of LRR in the latest Japanese cohort. Advances in systemic therapy might the main reason to reduce the LRR rate rather than PMRT in this population. The administration of PMRT should be tailored considering the individual risks of LRR, such as 3 node metastases. Citation Format: Akimitsu Yamada, Naoki Hayashi, Hiraku Kumamaru, Masayuki Nagahashi, Shiori Usune, Hiroaki Miyata, Takashi Ishikawa, Kazutaka Narui, Itaru Endo, Shigeru Imoto, Shinji Ohno, Hiromitsu Jinno. Prognostic impact of postmastectomy radiation therapy in breast cancer patients with T1, 2 and 1-3 lymph nodes from Japan Breast Cancer Registry [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-19-27.

Little is known with regard to patient-reported outcomes (PROs) in the setting of implant-based reconstruction (IBR) with post-mastectomy radiation therapy (PMRT). We identified patients who underwent immediate IBR from a prospectively compiled database. The Breast Reconstruction Satisfaction Questionnaire (BRECON-31) was scored and compared between patients with and without PMRT. Sixty-four women met the study criteria. Forty-eight did not receive PMRT and 16 did. Nine women had an unanticipated indication for PMRT. The PMRT group was similar to the control group with regard to baseline characteristics (ie, age, marital status, body mass index, tobacco use, and comorbidities). However, treatment and oncologic characteristics (eg, diagnosis, tumour characteristics, systemic therapy use) differed. Of all complications, only capsular contracture rates differed (1.2% vs 13%; P = .01). Of the 9 subscales, 7 showed no difference in satisfaction between the groups. Radiated women scored lower in the arm concerns and breast appearance subscales. Scores were similar whether the indication for PMRT had been anticipated or not. Women with immediate IBR scored similarly to their nonradiated counterparts across 7 of 9 domains of satisfaction. Arm concerns and breast appearance scores are lower with PMRT, likely secondarily to more extensive nodal procedures in higher stage patients and to the side effect profile of radiotherapy. Our findings are in line with the few available studies using other PRO tools to evaluate the impact of PMRT on patient satisfaction and studies objectively measuring the effect of PMRT on arm morbidity and cosmetic outcomes.

PurposeOur previous data showed that carriers of germline BRCA1/2 pathogenic variants (PV) with breast cancer (BC) treated with mastectomy without post-mastectomy radiation therapy (PMRT) had higher rates of loco-regional recurrence (LRR) compared to those who underwent PMRT or breast-conserving therapy (BCT), despite earlier stage BC. Our aim was to verify our previous findings in a larger cohort.MethodsClinical data were extracted from the medical records of BRCA1/2 mutation carriers with BC, treated at a single institution between 1/2006 and12/2022. The data included demographics, treatment modalities, and BC outcomes.ResultsA total of 464 patients with 484 primary tumors were analyzed. Of these, 48.3% mastectomies were performed: 66% (154) without PMRT (non-PMRT) and 34% (80) with PMRT; 51.8% (250) underwent BCT. The non-PMRT group had earlier disease stages at diagnosis (77.3% were Tis and T1N0 stage) compared to the PMRT and BCT groups (3.8% and 45%, respectively, p < 0.001). During the study period with a median follow-up time of 75 months (range 12–211), the LRR rate was 13% (20/154) in the non-PMRT cohort compared with 1.25% (1/80) in the PMRT group (p = 0.003), and 6.4% (16/250) in the BCT group (p = 0.03). Cumulative incidence of LRR at 5 and 15 years was 14.7%, and 16.6% in the non-PMRT, compared to 5.1% and 35% in the BCT group, respectively (p = 0.081). No significant difference in overall survival was observed (p = 0.202).ConclusionsThe timing and rates of LRRs differ according to the loco-regional therapy, which might indicate a different etiology driving these events.

The utility of immediate autologous breast reconstruction in patients likely to undergo radiation therapy remains controversial. The purpose of this study was to perform a quantitative outcomes assessment of patients undergoing immediate free-flap breast reconstruction and postmastectomy radiation therapy (PMRT). A retrospective chart review was performed of patients undergoing free-flap breast reconstruction by the senior authors (L.C.W. and J.M.S.) between 2005 and 2009. The treatment group included patients who underwent immediate free-flap breast reconstruction and received PMRT. The control group consisted of patients undergoing immediate breast reconstruction without PMRT. Variables assessed included postoperative complications and revision surgery. Four hundred seven women underwent immediate free-flap breast reconstruction for a total of 655 flaps. In the cohort that underwent unilateral reconstruction, there was a higher incidence of volume loss (28.26% vs 4.42%, P < 0.0001) and fat necrosis (19.57% vs 3.54%, P = 0.002) in the PMRT group. In the cohort that underwent bilateral reconstruction, there was a higher rate of volume loss for those in the PMRT group (19.75% vs 1.0%, P < 0.0001). However, for both patients who underwent unilateral reconstruction and those who underwent bilateral reconstruction, the PMRT group underwent similar rates of revision surgery. The cohort that underwent bilateral reconstruction experienced a higher incidence of volume loss in radiated perforator flaps (39%) vs muscle-sparing free transverse rectus abdominis myocutaneous flaps (12%; P = 0.013). Postmastectomy radiation therapy can result in volume loss and fat necrosis, yet there are no increases in other complications or revision procedures. The deleterious effects of PMRT do not preclude the decision for immediate autologous reconstruction.

BackgroundThe safety of postmastectomy radiation therapy (PMRT) after autologous breast reconstruction remains unclear. Therefore, we conducted a systematic review and meta-analysis to investigate the effects of PMRT on patients with breast cancer who underwent autologous breast reconstruction.MethodsA comprehensive literature search of English and Japanese articles until March 2021 was performed using PubMed/MEDLINE, the Cochrane Library, and Ichushi-Web. We included studies that compared the outcomes of patients with breast cancer who underwent immediate autologous breast reconstruction with and without PMRT. Outcomes including major complications, fat necrosis, and cosmetic results were assessed. Pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated using a random effects model.ResultsTen studies (two retrospective case-controlled and eight retrospective cohort studies) comprising 3,123 cases were included. The rate of major complications was slightly higher in the PMRT group compared to the no PMRT group, but the difference was not statistically significant (13.2% vs. 12.2%, OR 1.58, 95% CI 0.93–2.68, P = 0.09). In contrast, the rate of fat necrosis was significantly increased in the PMRT group (17.2% vs. 8.1%, OR 2.71, 95% CI 1.58–4.65, P = 0.0003). Data on cosmetic outcomes were limited and not pooled for the meta-analysis.ConclusionsPMRT following autologous breast reconstruction was associated with a higher risk of fat necrosis, but not with a significantly increased rate of major complications. With careful patient selection and monitoring, PMRT after autologous breast reconstruction can be considered a safe and acceptable treatment option.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12282-025-01806-3.

The purpose of this study was to determine the optimal timing of delayed microvascular breast reconstruction after completion of postmastectomy radiation therapy (PMRT). The authors evaluated whether the timing of reconstruction after PMRT completion affects the development of major postoperative complications. We hypothesize that delayed microvascular breast reconstruction can be safely performed within 12 months of PMRT completion. A retrospective chart review of microvascular, autologous breast reconstructions at Brigham and Women's Hospital from 2007 to 2019 was performed. Logistic regression analysis and marginal estimation methods were used to estimate the probability of any major complication (flap compromise requiring operative intervention, hematoma formation requiring evacuation, infection requiring readmission, and flap necrosis requiring operative debridement) occurring in 2-month intervals after PMRT. Patients were classified as having undergone reconstruction 0 to 12 months after PMRT (group 1), 12 to 18 months after PMRT (group 2), or 18 to 50 months after PMRT (group 3). A total of 303 patients were identified. All patients received postmastectomy radiation (n = 143 group 1, n = 57 group 2, n = 103 group 3). Mean follow-up time was 71.4 ± 38 months. Patients in group 1 were significantly younger and more likely to have undergone neoadjuvant chemotherapy (p < 0.05). Major complications occurred in 10% of patients. There was no significant difference in the development of major complications between the three groups (p = 0.57). Although not statistically significant, the probability of any major complication peaked 2 to 6 months after PMRT completion. There was no significant difference in major complications among patients who underwent delayed, microvascular breast reconstruction within versus beyond 1 year of PMRT completion. These findings suggest that delayed microvascular breast reconstruction can be safely performed beginning 6 months after PMRT completion.