Role Of Postmastectomy Radiation Therapy Research Articles

Postmastectomy radiation therapy in breast cancer patients with micrometastatic disease in sentinel node dissection: A cohort study and meta-analysis

AimThe potential role of postmastectomy radiation therapy (PMRT) on prognosis in patients with T1-2 breast cancer and micrometastatic disease in sentinel lymph node dissection (SLND) has not yet been established. The aim of this study was to investigate the impact of PMRT on prognosis in patients with T1-2 breast cancer and micrometastatic in SLND. MethodA register- and population-based cohort was utilized by identifying eligible patients on the research database BcBase 3.0. Multivariate Cox regression models were applied for survival outcomes. In addition, a systematic literature review and meta-analysis including all relevant studies on this topic was performed. ResultsIn total, 956 patients fulfilling the inclusion criteria were found through the BcBaSe 3.0 with 237 (25.0 %) receiving PMRT and 719 (75.0 %) not receiving PMRT. No statistically significant differences between the two patient groups in terms of neither breast cancer-specific (adjusted Hazard Ratio (HR): 0.49; 95 % Confidence Interval (CI): 0.14 – 1.73) nor overall survival (adjusted HR: 0.63; 95 % CI: 0.29 – 1.35) was found. In the pooled analyses after literature review, PMRT did not result in better breast cancer-specific (5 studies; pooled HR: 1.06; 95 % CI: 0.88–1.27; I2 = 1 %; low certainty of evidence) or overall survival (6 studies; pooled HR: 1.01; 95 % CI: 0.91–1.13; I2 = 10 %; low certainty of evidence). ConclusionPMRT does not seem to impact survival in patients with T1 or T2 breast cancer with micrometastatic disease in SLND. Considering the low level of evidence and the relatively short follow-up of included studies, caution in interpreting the results into clinical practice is suggested.

Postmastectomy Radiation in HER-2 Positive Breast Cancer after Neoadjuvant Therapy: Secondary Analysis of Two Randomized Trials

The role of postmastectomy radiation therapy (PMRT) following primary systemic therapy (PST) in HER-2 positive breast cancer (Her2+BC) remains poorly understood. The current study evaluates PMRT based on the pathological response to PST in Her2+BC. TRYPHAENA and NeoSphere are randomized phase II trials that investigated PST for Her2+BC. Our study is a pooled analysis of both trials, including 312 node-positive patients treated with HER-2 targeted PST followed by mastectomy with or without PMRT. The primary endpoint is loco-regional recurrence-free survival (LRRFS). Our analysis included 172 (55%) patients who achieved nodal pCR and 140 (45%) patients who did not. Patients with nodal pCR had a 5-year LRRFS of 97% with PMRT delivered in 98 patients (57%). Patients without nodal pCR had a 5-year LRRFS of 87% with PMRT delivered in 93 patients (66%). Patients with ypN1 (n = 62) disease who received PMRT (n = 40) had a 5-year LRRFS of 85% as compared to 89% in those who did not (n = 22); (p = 0.60). A significant LRRFS difference was noted in patients with ypN2-3 (n = 78) disease who received PMRT (n = 53) compared to those who did not (n = 25) (5-year LRRFS 92% vs. 75%; p = 0.019). On multivariate analysis, clinical nodal disease at diagnosis and nodal pCR were significantly associated with loco-regional recurrence (LRR). Her2+BC patients who achieve nodal pCR after PST have excellent loco-regional control which supports de-escalation of PMRT.

Post-mastectomy radiation therapy in HER-2 positive breast cancer after primary systemic therapy: Pooled analysis of TRYPHAENA and NeoSphere trials

PurposeThe role of post-mastectomy radiation therapy (PMRT) following primary systemic therapy (PST) in HER-2 positive breast cancer (Her2 + BC) remains poorly understood. The current study evaluates PMRT based on the pathological response to PST in Her2 + BC. Methods and materialsTRYPHAENA and NeoSphere are randomized phase II trials that investigated PST for Her2 + BC. Our study is a pooled analysis of both trials, including 312 node-positive patients treated with HER-2 targeted PST followed by mastectomy with or without PMRT. The primary endpoint is loco-regional recurrence-free survival (LRRFS). ResultsOur analysis included 172 (55%) patients who achieved complete nodal pathological response (ypN0) and 140 (45%) patients who did not. Patients with ypN0 had a 5-year LRRFS of 97% in both, the PMRT and no PMRT, groups (p = 0.94). Patients with ypN + had 5-year LRRFS of 89% in the PMRT group and 82% in the no PMRT group (p = 0.17). Patients with ypN1 (n = 62) disease who received PMRT (n = 40) had a 5-year LRRFS of 85% as compared to 89% in those who did not (n = 22); (p = 0.60). A significant LRRFS difference was noted in patients with ypN2-3 (n = 78) disease who received PMRT (n = 53) compared to those who did not (n = 25) (5-year LRRFS 92% vs. 75%; p = 0.019). On multivariate analysis, clinical nodal disease at diagnosis and ypN0 were significantly associated with loco-regional recurrence (LRR). ConclusionsHer2 + BC patients who achieve ypN0 after PST have excellent locoregional-control which supports de-escalation of PMRT. In contrast, patients with ypN2-3 disease derive significant benefit from PMRT. Clinical nodal stage at presentation and ypN0 status are significantly associated with LRR risk in Her2 + BC.

Abstract P1-10-07: Role of postmastectomy radiation therapy in breast cancer patients according to pathologic nodal status after neoadjuvant chemotherapy

Abstract Purpose: The role of post-mastectomy radiation therapy (PMRT) in breast cancer patients after neoadjuvant chemotherapy (NAC) is highly controversial. This study aimed to evaluate the impact of PMRT according to pathologic nodal status. Methods and Materials: We retrospectively reviewed 682 patients with clinical stage II-III breast cancer who underwent NAC and mastectomy from 2013 to 2017. Of total, 596 (87.4%) received PMRT and 86 (12.6%) did not. We investigated the relationship amongst locoregional recurrence-free survival (LRRFS), disease-free survival (DFS), overall survival (OS), and various prognostic factors. Subgroup analyses to identify the patients who may benefit from PMRT were also performed. Results: The median follow-up duration was 67 months. In ypN+ patients (n = 368, 51.2%), PMRT showed significant benefit for LRRFS, DFS, and OS (all p < 0.001). Based on multivariate analysis, histologic grade (HG) III (hazard ratio [HR] = 3.67, p = 0.002), lymphovascular invasion (LVI) (HR = 2.38, p = 0.045), and ypN2-3 (HR = 2.37, p = 0.02) were identified as significant risk factors for poor LRRFS. In ypN1 patients with more than two factors among (i) luminal subtype (ii) HG I-II and (iii) absence of LVI, PMRT showed no significant difference in LRRFS (p = 0.18). In ypN0 patients (n = 351, 48.8%), PMRT was not significantly associated with LRRFS, DFS, and OS. However, PMRT showed better LRRFS in triple-negative breast cancer (TNBC) subtype (p = 0.04). Conclusion: PMRT had a high impact on treatment outcomes in patients with residual lymph nodes following NAC and mastectomy. Among the ypN0 patients, PMRT may be beneficial only in the TNBC subtype. Citation Format: Dowook Kim, Jin Ho Kim, In Ah Kim, Ji Hyun Chang, Kyung Hwan Shin. Role of postmastectomy radiation therapy in breast cancer patients according to pathologic nodal status after neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-10-07.

The impact of postmastectomy radiotherapy on cT1-2N1 breast cancer patients with ypN0 after neoadjuvant chemotherapy: a retrospective study based on real-world data

BackgroundThe role of postmastectomy radiation therapy (PMRT) in clinical T1-2N1 breast cancer patients who achieve axillary pathological complete response (ypN0) after neoadjuvant chemotherapy (NAC) is controversial.MethodsData from cT1-2N1 breast cancer patients who converted to ypN0 after NAC and subsequent surgery were retrospectively analyzed. Disease-free survival (DFS) and overall survival (OS) were estimated using the Kaplan‒Meier method. Univariate and multivariate Cox regression models were applied to investigate the correlations between clinical or pathological parameters and survival.ResultsFrom 2012–2019, we identified 116 cases for analysis, including 31 (26.7%) who received PMRT and 85 (73.3%) who did not. At a median follow-up time of 56.4 months, the 5-year DFS and OS rates were 90.2% and 96.7% with PMRT and 93.7% and 97.3% without PMRT, respectively. PMRT did not affect either DFS (p = 0.234) or OS (p = 0.878). On multivariate analyses, no differences in DFS or OS between the two groups were detected, taking into consideration the following factors: age, molecular subtype, Ki67 index, cT stage, and in-breast pathologic complete response (DFS: HR 2.260; 95% CI 0.465–10.982; p = 0.312. OS: HR 1.400; 95% CI 0.138–14.202; p = 0.776). This nonsignificant difference was also consistent in subgroup analyses (all p > 0.05).ConclusionsPMRT has limited ability to confer DFS or OS benefits for cT1-2N1 breast cancer patients who achieved axillary pathological complete response after NAC and total mastectomy. It is imperative to conduct prospective studies to investigate the safety and feasibility of omitting PMRT.Trial registration: This research was approved by the Ethics Committee of The First Affiliated Hospital of Chongqing Medical University (ID: No. 2021–442).

The Role of Post-Mastectomy Radiation Therapy in Patients with pT3N0 Breast Cancer and Low Genomic Recurrence Score

<h3>Purpose/Objective(s)</h3> The role of post-mastectomy radiotherapy (PMRT) in patients with pT3 pN0 breast cancer remains controversial. We previously showed a correlation between PMRT and improved overall survival (OS) in pT3N0 patients who do not receive chemotherapy. However, it is unknown whether this correlation extends to patients with low genomic recurrence score (RS). In this analysis, we used the National Cancer Database (NCDB) to investigate the benefit of PMRT in pT3N0 patients with low RS. <h3>Materials/Methods</h3> We performed an analysis of NCDB patients with pT3N0 breast cancer who had low Oncotype DX RS (ORS) (< 25) and did not receive systemic chemotherapy. Patients were matched for baseline patient, tumor, and treatment characteristics using inverse probability of treatment weighting to minimize the impact of potential confounding variables. We stratified patients based on receipt of PMRT and compared OS using Kaplan-Meier estimates. Univariate and doubly-robust multivariable analyses were used to correlate PMRT and various baseline characteristics with OS. <h3>Results</h3> We identified 444 patients with pT3N0 breast cancer who had undergone mastectomy and had low-risk genomic assay scores who did not receive systemic chemotherapy. After IPTW matching, there were no significant differences in baseline patient characteristics. In the PMRT group, 44% received treatment to the chest-wall only, and 66% patients received chest wall and regional nodal irradiation. PMRT was associated with improved overall survival on both the univariate (HR=0.201; 95% CI=0.05-0.78; p=0.021) and doubly-robust multivariable analyses (HR=0.128; 95% CI=0.02-0.66; p=0.014). Receipt of endocrine therapy was also found to significantly improve overall survival (p=0.02). We attempted to repeat the analysis in patients with RS >25 who received chemotherapy, but we only identified a total of 78 such patients and could not perform a robust analysis. <h3>Conclusion</h3> This cohort analysis shows a strong correlation between PMRT and improved OS in pT3N0 patients with low ORS who do not receive chemotherapy. It is possible that with the de-escalation of chemotherapy and axillary surgery in this patient population in the modern era, the benefit of locoregional treatment with radiotherapy is magnified. Our analysis suggests that prospective data are needed before de-escalation of radiotherapy for these patients based on ORS.

Effect of Postmastectomy Radiotherapy in Breast Cancer Patients according to Pathologic Nodal Status and Molecular Subtype after Neoadjuvant Chemotherapy

<h3>Purpose/Objective(s)</h3> The role of post-mastectomy radiation therapy (PMRT) in breast cancer patients who have achieved ypN0 after neoadjuvant chemotherapy (NAC) has not yet been established. This study aimed to evaluate the benefit of PMRT according to pathologic node status and molecular subtype in breast cancer patients who were treated NAC. <h3>Materials/Methods</h3> We retrospectively reviewed 511 patients with clinical stage II-III breast cancer who underwent NAC and mastectomy at our institution from 2013 to 2017. After mastectomy, ypN+ and ypN0 were identified in 289 (56.6%) and 222 (43.4%), respectively. In this study, molecular subtypes were classified according to hormone receptor (HR) and HER2 receptors as follows: luminal (HR+/HER2-), luminal-HER2 (HR+/HER2+), HER2 enriched (HR-/HER2+), triple-negative (HR -/HER2-). All HER2-positive patients were treated with trastuzumab-containing NAC. Of the total patients, 448 (87.7%) received PMRT and 63 (12.3%) did not. In ypN+ patients, PMRT was performed in 265 (91.7%) and 24 (8.3%) did not. In ypN0 patients, PMRT was performed in 183 (82.4%) and 39 (17.6%) did not. The effect of PMRT on locoregional recurrence-free survival (LRRFS), disease-free survival (DFS), and overall survival (OS) was evaluated based on pathologic nodal status and molecular subtypes. <h3>Results</h3> The median follow-up duration was 58 months. The cumulative incidence of locoregional recurrence and distant metastasis were 11.8% and 31.5% in ypN+ patients, and 6.8% and 13.5% in ypN0 patients, respectively. In ypN+ patients, PMRT showed significant benefit for LRRFS, DFS, and OS in multivariate analysis (all P < 0.001). In ypN0 patients, triple-negative subtype and lymphovascular invasion were significant prognostic factors for LRRFS (all P < 0.001) and DFS (P = 0.002 and P < 0.001, respectively) by multivariate analysis. However, in ypN0 patients, PMRT was not significantly associated with LRRFS, DFS, and OS. In addition, PMRT showed no significant difference in LRRFS in all molecular subtypes of ypN0 patients. <h3>Conclusion</h3> PMRT should be performed in patients with residual lymph node following NAC and mastectomy. Although a limited number of patients, this study suggests that the role of PMRT in ypN0 patients regardless of subtype remains unclear.

Isolated Tumor Cells and Micrometastatic Nodal Disease in Breast Cancer Patients After Neoadjuvant Chemotherapy: Is Post Mastectomy Radiation Therapy Indicated?

<h3>Purpose/Objective(s)</h3> The prognostic and treatment implications of isolated tumor cells (ypN0i+) and micrometastatic (ypN1mi) nodal disease after neoadjuvant chemotherapy (NACT) is not well-studied. These patients are excluded from the ongoing NSABP B-51 trial which only includes patients with macroscopic nodal disease after NACT. We evaluate the long-term outcomes and the role of post-mastectomy radiation therapy (PMRT) in breast cancer patients with ypN0i+ and ypN1mi disease after NACT and mastectomy (MX). <h3>Materials/Methods</h3> Using the National Cancer Database (NCDB), we identified patients (≥ 18 year old) with breast cancer who were treated with NACT and MX diagnosed between 2004 and 2016. Patients with cT4 or metastatic disease were excluded. Chi-square testing was used to evaluate clinicopathological parameters of those treated with and without PMRT. Kaplan-Meier analysis was used to evaluate the effect of PMRT on overall survival (OS). Univariate and multivariate Cox proportional hazard models with and without inverse probability treatment weighting (IPTW) were used to identify prognostic factors associated with OS. <h3>Results</h3> Our final cohort consisted of 3,253 patients (34.0% ypN0i+, 66.0% ypN1mi) with a median age at diagnosis of 49 years (29 – 74 years). PMRT was utilized in 60.4% of the entire cohort, 51.8% of ypN0i+ patients and in 64.9% of ypN1mi patients. There was an increase in use of PMRT throughout the study period (56.2% in 2004-2011 vs. 61.9% in 2012-2016). With a median follow up of 36.8 months, the 5-year OS was 84.3% and 79.9% for ypN0i+ and ypN1mi patients, respectively (HR 1.23 [0.97-1.55], <i>P</i> = 0.092). Without accounting for covariates, there was no significant effect of PMRT on OS in ypN0i+ patients, ypN1mi patients, or in the entire cohort. In IPTW-MVA, PMRT had no significant effect on OS (HR 0.93 [0.74-1.18], <i>P</i> = 0.565]. Factors that were significant for worse OS on IPTW-MVA were higher comorbidity score, higher grade, hormone-receptor negative subtype, higher ypT stage, presence of lymphovascular invasion, Asian/Pacific Islander race, and more recent year of diagnosis. HER-2 positive subtype, receipt of hormone therapy, and private insurance were associated with improved OS. <h3>Conclusion</h3> Patients with ypN1mi disease had a trend towards worse OS in comparison to patients with ypN0i+ disease. The majority of patients with ypN0i+ and ypN1mi are receiving PMRT with higher rates of PMRT in ypN1mi vs. ypN0i+. PMRT rates are increasing with time. There is no association of PMRT with improved OS. Prospective randomized controlled data is needed to further evaluate the role of PMRT in these patients who were excluded from the ongoing NSABP B-51.

Postmastectomy Radiation Therapy for Node-Negative Breast Cancer of 5 cm or Larger Tumors: A Multicenter Retrospective Analysis (KROG 20-03).

PurposeThis study aimed to evaluate the role of postmastectomy radiation therapy (PMRT) in patients with node-negative breast cancer of 5cm or larger tumors undergoing mastectomy.Materials and MethodsMedical records of 274 patients from 18 institutions treated with mastectomy between January 2000 and December 2016 were retrospectively reviewed. Among these, 202 patients underwent PMRT, while 72 did not. Two hundred and forty-one patients (88.0%) received systemic chemotherapy, and 172 (62.8%) received hormonal therapy. Patients receiving PMRT were younger, more likely to have progesterone receptor-positive tumors, and received adjuvant chemotherapy more frequently compared with those without PMRT (p < 0.001, p=0.018, and p < 0.001, respectively). Other characteristics were not significantly different between the two groups.ResultsWith a median follow-up of 95 months (range, 1 to 249 months), there were nine locoregional recurrences, and 20 distant metastases. The 8-year locoregional recurrence-free survival rates were 98.0% with PMRT and 91.3% without PMRT (p=0.133), and the 8-year disease-free survival (DFS) rates were 91.8% with PMRT and 73.9% without PMRT (p=0.008). On multivariate analysis incorporating age, histologic grade, lymphovascular invasion, hormonal therapy, chemotherapy, and PMRT, the absence of lymphovascular invasion and the receipt of PMRT were associated with improved DFS (p=0.025 and p=0.009, respectively).ConclusionLocoregional recurrence rate was very low in node-negative breast cancer of 5 cm or larger tumors treated with mastectomy regardless of the receipt of PMRT. However, PMRT was significantly associated with improved DFS. Further investigation is needed to confirm these findings.

New Frontiers in Hypofractionation for Regional Nodal Irradiation in Breast Cancer

In recent years, there have been a number of small, yet notable practice changes in the delivery of postmastectomy radiation therapy (PMRT) in breast cancer patients. Herein, we describe the role of PMRT and its evolving delivery with hypofractionated regimens. The UK START trials and whole-breast hypofractionation studies established the safety and effectiveness of accelerated radiotherapy. This has inspired further investigations of similar principles in patients with reconstruction, acute and late toxicities associated with hypofractionated regimens, socioeconomic benefit, and evolving delivery techniques. Overall, results from clinical trials evaluating hypofractionation for RNI or PMRT appear promising despite the limited length of follow-up. Ongoing clinical trials will provide valuable data on the safety of hypofractionation in breast cancer patients with immediate reconstruction. Hypofractionation for PMRT represents high-quality care that is not only more convenient for patients but also more cost-effective for the healthcare system.

Postmastectomy Radiation Therapy Based on Pathologic Nodal Status in Clinical Node-Positive Stage II to III Breast Cancer Treated with Neoadjuvant Chemotherapy

The present study aimed to evaluate the effect of postmastectomy radiation therapy (PMRT) after neoadjuvant chemotherapy in patients with node-positive stage II to III (cT1-4N1-2M0) breast cancer. A total of 1813 patients from 12 institutions were retrospectively reviewed. Patients were classified into 1 of 3 groups based on the pathologic lymph node status after neoadjuvant chemotherapy: ypN0, ypN1, and ypN2-3. The role of PMRT was separately evaluated in each group. Locoregional control, disease-free survival, and overall survival (OS) were estimated using the Kaplan-Meier method. The effect of PMRT was assessed by propensity score-matched analyses and multivariate Cox analyses. With a median follow-up of 72.9 months, 5-year locoregional control, disease-free survival, and OS rates were 86.3%, 68.4%, and 83.1% for the entire cohort, respectively. There were 490 (27.0%), 567 (31.3%), and 756 (41.7%) patients in the ypN0, ypN1, and ypN2-3 groups, respectively. PMRT significantly improved 5-year OS in the ypN2-3 group (74.2% vs 55.9%; P < .001) but had no effect on 5-year OS in the ypN0 group (93.1% vs 95.5%; P = .517) and ypN1 group (88.4% vs 87.8%; P = .549). With modern systemic therapy, PMRT significantly improved OS in the ypN2-3 group but not in the ypN0 and ypN1 groups. Whether PMRT can be safely omitted in the ypN0 and ypN1 groups should be addressed prospectively.

When Can We Avoid Postmastectomy Radiation Following Primary Systemic Therapy?

Postmastectomy radiation therapy (PMRT) has been shown to reduce the risk of locoregional recurrences (LRR) and of distant metastases (DM) and to improve breast cancer-specific survival (BCSS) as well as overall survival (OS) in patients with locally advanced breast cancer who are considered high risk because of large tumors (> 5cm) and/or presence of axillary lymph node involvement. Controversy is still ongoing with respect to the indication of PMRT in the case of earlier stage invasive tumors in the presence of risk factors including young age, premenopausal status, presence of lymphovascular invasion (LVI), high tumor grade, or tumor size 2-5cm. Simultaneously, the evolution of our understanding of breast cancer biology has led us to better identify patients for whom the administration of systemic treatment prior to surgery reduces tumor load, not only in the case of locally advanced tumors but also for earlier stages, namely in the case of unfavorable molecular subtypes. The role of PMRT in the context of these patients treated with primary systemic therapy (PST), especially after a good tumor response, is under evaluation by various studies. This review identifies factors that may permit PMRT omission in a selected group of patients after PST.

Evaluating the Role of Postmastectomy Radiation Therapy Based on Pathological Nodal Response in Clinical Nodal Positive Stage II-III Breast Cancer after Neoadjuvant Chemotherapy: A Multicenter Study of 1963 Cases from China

Evaluating the Role of Postmastectomy Radiation Therapy Based on Pathological Nodal Response in Clinical Nodal Positive Stage II-III Breast Cancer after Neoadjuvant Chemotherapy: A Multicenter Study of 1963 Cases from China

Whether adjuvant radiotherapy is desired for postmastectomy patients with T1–T2 tumors and 1–3 positive axillary lymph nodes who received modern systemic therapy?

The role of postmastectomy radiation therapy (PMRT) for patients with T1–T2 tumors and 1–3 positive axillary lymph node (ALN) metastases of breast cancer is an issue of ongoing debate. The uncertainty and controversy concerning PMRT for this group of patients is mainly due to the discrepancy in the conflicting benefits of locoregional control reported in different trials and in adjuvant systemic treatment eras (1-4).

ASO Author Reflections: The Role of Post-mastectomy Radiation Therapy in the Setting of Nodal Micrometastases.

ASO Author Reflections: The Role of Post-mastectomy Radiation Therapy in the Setting of Nodal Micrometastases.

The Evolving Role of Postmastectomy Radiation Therapy.

Throughout various eras of breast cancer therapy, postmastectomy radiation therapy (PMRT) has played an important role in the treatment of locally advanced breast cancer. PMRT decreases locoregional recurrence and may improve overall survival in patients with tumors over 5cm or positive lymph nodes. As novel cancer therapies improve survival in breast cancer, the role of radiation therapy is evolving. Individualized recommendations for PMRT dependent on pathologic response after neoadjuvant systemic therapy are under investigation. This review summarizes the role of PMRT during breast cancer therapy and discusses open questions that may change the landscape of future breast cancer treatment.

Practical consensus recommendations regarding role of postmastectomy radiation therapy.

The use of radiation therapy after mastectomy (PMRT) has been limited to those patients who are at significant risk of cancer recurring in the chest wall or in the nodal basins. The use of PMRT has been widely accepted for patients with four or more positive lymph nodes,[1],[2] but there is still controversy regarding the value of PMRT for those with one to three positive nodes. This expert group used data from published literature, practical experience and opinion of a large group of academic oncologists to arrive at these practical consensus recommendations for the benefit of community oncologists.

Abstract ES1-2: Guidelines for postmastectomy radiotherapy

Abstract A joint panel of the American Society of Clinical Oncology (ASCO), American Society for Radiation Oncology (ASTRO), and Society of Surgical Oncology (SSO) convened in 2015 to develop an update of the prior ASCO guideline (J Clin Oncol 2001;19:1539-1569) concerning the use of postmastectomy radiation therapy (PMRT). This effort focused on common scenarios where there have been substantial controversy. Their conclusions and supporting evidence have been published (J Clin Oncol 2016;34:4431-4442). The Panel unanimously agreed that PMRT reduces the risks of local-regional failure (LRF), any recurrence, and breast cancer mortality for patients with T1-2 breast cancer with 1-3 positive axillary nodes. However, some subsets of these patients are likely to have such a low risk of LRF that the absolute benefit of PMRT is outweighed by its potential toxicities. The Panel however could not find sufficient evidence to recommend a specific formula or method of how to combine clinical, pathologic, and biologic data to calculate the risk of LRF. In addition, the acceptable ratio of benefit to toxicity varies among patients and physicians. Thus, the decision to recommend PMRT or not requires a great deal of clinical judgement. The Panel agreed clinicians making such recommendations for an individual patient should consider factors that may decrease the risk of LRF, attenuate the benefit of reduced breast cancer-specific mortality, and/or increase the risks of complications from PMRT. When clinicians and patients elect to omit axillary dissection after a positive sentinel node biopsy, the Panel recommended that these patients receive PMRT only if there is already sufficient information to justify its use without needing to know that additional axillary nodes are involved. Patients with axillary nodal involvement following neoadjuvant systemic therapy should receive PMRT. The role of PMRT in other patients with clinical Stage I or II breast cancer is uncertain. Finally, the Panel recommended that radiation therapy generally be given to both the internal mammary nodes and the supraclavicular-axillary apical nodes in addition to the chest wall or reconstructed breast when PMRT is used. However, there may be subgroups that will have limited, if any, benefits from treating both these nodal areas compared to treating only one of them or, perhaps, treating only the chest wall or reconstructed breast. There is insufficient evidence at this time to define such subgroups in detail. This lecture will address selected elements of the data leading to the Panel's decisions. Citation Format: Recht A. Guidelines for postmastectomy radiotherapy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr ES1-2.

The role of postmastectomy radiation therapy in patients with immediate prosthetic breast reconstruction: A meta-analysis.

Objective:The controversy remains as to whether immediate prosthetic breast reconstruction with postmastectomy radiation therapy (PMRT) is associated with acceptable complications and aesthetic outcomes. The aim of this meta-analysis was to provide a pooled analysis of comparative clinical studies that evaluated breast cancer patients who were treated with a mastectomy and an immediate prosthetic breast reconstruction to compare the complications and satisfaction of those who underwent or did not undergo PMRT.Methods:According to the recommendations of the Cochrane Collaboration, we established a rigorous study protocol. We performed a systematic electronic search of the PubMed and Embase databases to identify articles for inclusion in our meta-analysis. Reconstruction failure, overall complications, capsular contracture, and patient satisfaction were analyzed individually.Results:Fifteen controlled trials were included, comprising 5314 patients (1069 PMRT vs 4245 non-PMRT). Primary outcomes revealed a statistically significant increase in overall complications [odds ratio (OR) 3.45; 95% confidence interval (95% CI) 2.62–4.54; P < .00001], reconstruction failure (OR: 2.59; 95% CI 1.46–4.62; P = .001), and capsular contracture (OR: 5.26, 95% CI: 2.73–10.13, P < .00001) after receiving PMRT.Conclusion:Our review found that PMRT for patients who underwent immediate implant-based breast reconstruction led to higher risks of reconstruction failure, overall complications, and capsular contracture. However, it is still the standard adjuvant therapy for mastectomy patients who have opted for immediate implant-based breast reconstruction.

Role of postmastectomy radiation therapy in breast cancer patients with different pathological responses to neoadjuvant chemotherapy

AbstractObjectiveThe purpose of the present study was to investigate the role of postmastectomy radiation therapy (PMRT) after neoadjuvant chemotherapy in breast cancer patients of clinical stage II–III with different pathological responses to neoadjuvant chemotherapy.MethodsWe retrospectively analyzed 79 clinical stage II–III breast cancer patients who underwent mastectomy after neoadjuvant chemotherapy between 2008 and 2013. According to the Miller–Payne grading system, we defined grades 1–2 as the poor response group, and grades 3–5 as the good response group. The 5‐year curves for locoregional recurrence free survival (LRRFS), distant disease‐free survival, and overall survival were constructed using the Kaplan–Meier method, and compared using the log–rank test.ResultsFor all patients, the median age was 48 years (range 29–68 years). At a median follow up of 56 months, the 5‐year LRRFS was 97.8% and 81.8% (P = 0.01), the 5‐year distant disease‐free survival was 73.9% and 75.8% (P = 0.14), and the 5‐year overall survival for both was 84.8% (P = 0.96). In the subgroup analysis, the LRRFS, distant disease‐free survival, and overall survival of the subgroup with a good response did not benefit from PMRT. However, the LRRFS of the poor response subgroup can significantly benefit from PMRT (P = 0.04).ConclusionsPMRT was effective in reducing the local‐regional recurrence rate for patients with a Miller–Payne grade 1–2; therefore, we suggest that PMRT should be considered for these patients.