Effectiveness of the AJCC 8th edition staging system for selecting patients with T1-2N1 breast cancer for post-mastectomy radiotherapy: a joint analysis of 1986 patients from two institutions

The significance of risk stratification through nomogram-based assessment in determining postmastectomy radiotherapy for patients diagnosed with pT1 - 2N1M0 breast cancer

OBJECTIVE

To explore the high-risk factors affecting the prognosis of pT1 - 2N1M0 patients after mastectomy, establish a nomogram prediction model, and screen the radiotherapy benefit population.

METHOD

The clinical data of 936 patients with pT1 - 2N1M0 who underwent mastectomy in the fourth hospital of Hebei Medical University from 2010 to 2016 were retrospectively analyzed. There were 583 patients received postmastectomy radiotherapy(PMRT), and 325 patients without PMRT. Group imbalances were mitigated using the propensity score matching (PSM) method, and the log-rank test was employed to compare overall survival (OS) and disease-free survival (DFS) between the cohorts. The efficacy of PMRT across various risk groups was evaluated using a nomogram model.

RESULT

The median follow-up period was 98 months, Patients who received PMRT demonstrated significantly improved 5-year and 8-year OS and DFS compared to those who did not (P < 0.001). Multivariate analysis revealed that age, primary tumor site, positive lymph node, stage, and Ki-67 level independently influenced OS, while age, primary tumor site, and stage independently affected DFS. PMRT drastically enhanced OS in the high-risk group (P = 0.001), but did not confer benefits in the low-risk and intermediate risk groups (P = 0.057, P = 0.099). PMRT led to a significant improvement in disease-free survival (DFS) among patients in the intermediate and high-risk groups (P = 0.036, P = 0.001), whereas the low-risk group did not experience a significant benefit (P = 0.475).

CONCLUSION

Age ≤ 40 years, tumor located in the inner quadrant or central area, T2 stage, 2-3 lymph nodes metastasis, and Ki67 > 30% were the high-risk factors affecting the prognosis of this cohort of patients. In OS nomogram, patients with a risk score of 149 or higher who received PMRT exhibited improved OS. Similarly, in DFS nomogram, patients with a risk score of 123 or higher who received PMRT demonstrated enhanced DFS.

RecurIndex-Guided postoperative radiotherapy with or without Avoidance of Irradiation of regional Nodes in 1-3 node-positive breast cancer (RIGAIN): a study protocol for a multicentre, open-label, randomised controlled prospective, phase III trial

INTRODUCTION

Postoperative radiotherapy in patients with breast cancer with one to three lymph node metastases, particularly within the pT1-2N1M0 cohort with a low clinical risk of local-regional recurrence (LRR), has incited a discourse surrounding personalised treatment strategies. Multigene testing for Recurrence Index (RecurIndex) model capably differentiates patients based on their level of LRR risk. This research aims to validate whether a more aggressive treatment approach can enhance clinical outcomes in N1 patients who possess a clinically low risk of LRR, yet a high RecurIndex-determined risk of LRR. Specifically, this entails postoperative whole breast irradiation combined with regional lymph node irradiation (RNI) following breast-conserving surgery or chest wall irradiation with RNI after mastectomy.

METHODS AND ANALYSIS

The RIGAIN (RecurIndex-Guided postoperative radiotherapy with or without Avoidance of Irradiation of regional Nodes in 1-3 node-positive breast cancer) Study is a multicentre, prospective, randomised, open-label, phase III clinical trial that is being conducted in China. In this study, patients with low clinical LRR risk but high RecurIndex-LRR risk are randomly assigned in a 1:1 ratio to the experimental group or the control group. In the experimental group, RNI is performed and the control group omits RNI. Efficacy and safety analyses will be conducted, enrolling a total of 540 patients (270 per group). The primary endpoint is invasive disease-free survival, and secondary endpoints include any first recurrence, LRR-free survival, distant metastasis-free survival, recurrence-free survival, overall survival, disease-free survival, breast cancer-specific mortality and assessment of patient quality of life. The study began in April 2023 and with a follow-up period of 60 months after the last participant completes radiation therapy.

ETHICS AND DISSEMINATION

The study was approved by the Ethics Committee of Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University (SYSKY-2022-097-02, V.3.1). It adheres to the Helsinki Declaration and Good Clinical Practice. Research findings will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04069884.

De-escalated radiotherapy for HER2-overexpressing breast cancer patients with 1-3 positive lymph nodes undergoing anti-HER2 targeted therapy

Background

In the era of anti-HER2 targeted therapy, the potential clinical feasibility of considering HER2-overexpressing breast cancer cases presenting with 1-3 positive axillary lymph nodes as low-risk, and thereby contemplating postoperative radiotherapy reduction, remains an important subject for in-depth examination. The aim of this retrospective study was to evaluate the effectiveness of de-escalated radiotherapy in T1-2N1M0 HER2-overexpressing breast cancer patients receiving anti-HER2 targeted therapy. Specifically, omitting regional lymph node irradiation (RNI) after breast-conserving surgery and only performing whole-breast irradiation or omitting postmastectomy radiation therapy.

Methods

A retrospective analysis was conducted on 429 patients with stage T1-2N1M0 primary invasive HER2-overexpressing breast cancer from our center between 2004 and 2018. Patients who received anti-HER2 targeted therapy were divided into an RNI group and a no RNI group to assess the role of RNI. The prognostic role of RNI was investigated via the Kaplan-Meier method and Cox proportional hazards modeling.

Results

The median follow-up time was 46.8 months (range 7.1-225.8 months). In the anti-HER2 targeted therapy group RNI yielded no significant improvements in invasive disease-free survival (IDFS) (p = 0.940), local-regional recurrence-free survival (p = 0.380), distant metastases-free survival (p = 0.698), or overall survival (p = 0.403). Estrogen receptor (ER) status (hazard ratio [HR] 0.105, 95% confidence interval [CI] 0.023-0.749, p = 0.004) and lymph vascular invasion status (LVI) (HR 5.721, 95% CI 1.586-20.633, p = 0.008) were identified as independent prognostic factors for IDFS, and ER-positive and LVI-negative patients exhibited better prognoses.

Conclusion

Omitting RNI may be a safe option in T1-2N1 HER2-overexpressing breast cancer patients receiving standardized anti-HER2 targeted therapy; particularly in ER-positive or LVI-negative subgroups.

Breast Cancer: An Overview of Current Therapeutic Strategies, Challenge, and Perspectives

Breast cancer is the most commonly diagnosed cancer and the leading cause of death among female patients, which seriously threatens the health of women in the whole world. The treatments of breast cancer require the cooperation of a multidisciplinary setting and taking tumor load and molecular makers into account. For early breast cancer, breast-conserving surgery with radiotherapy or mastectomy alone remains the standard management, and the administration of adjuvant systemic therapy is decided by the status of lymph nodes, hormone receptors, and human epidermal growth factor receptor-2. For metastatic breast cancer, the goal of treatments is to prolong survival and maintain quality of life. This review will present the current advances and controversies of surgery, chemotherapy, radiotherapy, endocrine therapy, targeted therapy, immunotherapy, gene therapy, and other innovative treatment strategies in early-stage and metastatic breast cancer.

Postmastectomy radiotherapy in patients with T1-2N1 breast cancer: a single center experience and a meta-analysis

PURPOSE

Postmastectomy radiotherapy (PMRT) in patients with T1-2N1 breast cancer is still controversial. This study was to evaluate the survival prognosis of T1-2N1 patients with or without PMRT.

PATIENTS AND METHODS

From January 2006 to May 2017, 2606 female breast cancer patients underwent mastectomy in our medical center, among whom 402 patients of T1-2N1 stage with or without PMRT were finally analyzed. The median follow-up duration was 59.5 months. The primary endpoint was overall survival (OS). The secondary endpoint was disease-free survival (DFS).

RESULTS

In the study of our center, no statistically significant difference was observed between the T1-2N1 PMRT and non-PMRT subgroups for the 5-year OS (94.4% vs 95.4%, p = 0.667) and DFS (90.1% vs. 91.1%, p = 0.798). By the date of the last follow-up, 8.96% (n = 36) of the patients experienced any recurrence. Univariate analysis revealed that PMRT was not a prognostic factor for either OS (p = 0.667) or DFS (p = 0.798) in T1-2N1 patients. We then did a meta-analysis on the current treatment patterns, in which 2606 PMRT and 4281 non-PMRT T1-2N1 breast cancer patients with mastectomy were included. The meta-analysis showed that PMRT didn't improve the OS of the patients (HR = 0.85, p = 0.11), but patients with PMRT had better DFS than those in the non-PMRT group (HR = 0.62, p < 0.001).

CONCLUSION

PMRT did not affect the survival of T1-2N1 breast cancer patients who underwent mastectomy, suggesting that radiotherapy may be safely omitted for them.

Enhanced E6AP-mediated ubiquitination of ENO1 via LINC00663 contributes to radiosensitivity of breast cancer by regulating mitochondrial homeostasis

Radiotherapy has shown measurable efficacy in breast cancer (BC). Elucidating the mechanisms and developing effective strategies against resistance, which is a major challenge, is crucial. Mitochondria, which regulate homeostasis of the redox environment, have emerged as a radiotherapeutic target. However, the mechanism via which mitochondria are controlled under radiation remains elusive. Here, we identified alpha-enolase (ENO1), as a prognostic marker for the efficacy of BC radiotherapy. ENO1 enhances radio-therapeutic resistance in BC via reducing the production of reactive oxygen species (ROS) and apoptosis in vitro and in vivo through modulation of mitochondrial homeostasis. Moreover, LINC00663 was identified as an upstream regulator of ENO1, which regulates radiotherapeutic sensitivity by downregulating ENO1 expression in BC cells. LINC00663 regulates ENO1 protein stability by enhancing the E6AP-mediated ubiquitin-proteasome pathway. In BC patients, LINC00663 expression is negatively correlated with ENO1 expression. Among patients treated with IR, those who did not respond to radiotherapy expressed lower levels of LINC00663 than those sensitive to radiotherapy. Our work established LINC00663/ENO1 critical to regulate IR-resistance in BC. Inhibition of ENO1 with a specific inhibitor or supplement of LINC00663 could be potential sensitizing therapeutic strategies for BC.

Delayed-immediate breast reconstruction: An assessment of complications and outcomes in the context of anticipated post-mastectomy radiotherapy

INTRODUCTION

The detrimental effects of post-mastectomy radiotherapy on breast reconstruction are well known. We report our experience with a delayed-immediate approach involving an initial subcutaneous implant with definitive reconstruction after adjuvant radiotherapy.

METHODS

Patients were identified retrospectively from hospital, theatre and implant registry records. Details regarding demographics, cancer pathology, surgical data and oncological therapies were collected. Primary outcomes included complication rates of first-stage surgery and time to definitive reconstruction.

RESULTS

A total of 115 patients underwent mastectomy and temporary subcutaneous implant (36 nipple sparing) between 2008 and 2019. Five were smokers with eleven having a body mass index > 30. The median age was 46 years (27-76 years) and tumour size 50 mm. Almost 95% underwent radiotherapy, 82% chemotherapy and 70% had axillary node clearance. Median mastectomy weight was 464 g (123-1300 g) with median temporary implant volume 375 cc (180-655 cc). Complications of first-stage surgery at three months included 5.2% implant loss (n = 6), 14.8% infection rate, 17.4% readmission rate and 10.4% returned to theatre. Reconstructive failure occurred in four cases (3.5%). A total of 76 patients completed definitive reconstruction, including 26 autologous, 21 latissimus dorsi with implant, and 28 implant-only reconstructions. The median time to reconstruction following the completion of radiotherapy was 12 months. This increased in those who had implant complications (28 vs. 15 months) or radiotherapy (16 vs. 10 months) versus those without.

CONCLUSIONS

Delayed-immediate breast reconstruction using a temporary subcutaneous implant has been shown to be a safe, feasible and potentially beneficial method than simple mastectomy and delayed reconstruction with a complication rate comparable to that of immediate implant reconstruction.

The Value of the 8th Edition of American Joint Committee on Cancer Pathological Prognostic Staging on the Selection of Postmastectomy Radiotherapy for T1-2N1 Breast Cancer

Methods and Materials

Patients diagnosed with pT1-2N1M0 breast cancer between 2008 and 2018 in West China Hospital, Sichuan University were included. Locoregional-free survival (LRFS), distant metastasis-free survival (DMFS), disease-free survival (DFS), breast cancer-specific survival (BCSS), and overall survival (OS) were defined as endpoints. The propensity score matching (PSM), receiver operating characteristic (ROC) curve, the Kaplan-Meier analysis, and the Cox multivariable model were used for data analysis.

Results

We identified 1,615 patients with T1-2N1M0 breast cancer, and 44.9% (n = 744) of them were treated with PMRT. With a median follow-up of 76 months, 46 (2.8%) recurrences, 96 (5.9%) deaths, and 80 (5.0%) breast cancer-related deaths occurred. The 5-year LRFS, DMFS, DFS, BCSS, and OS were 98.6%, 95.3%, 93.7%, 96.5%, and 96.0%, respectively. PMRT could not improve 5-year LRFS, DMFS, DFS, BCSS, and OS compared with non-PMRT neither before nor after PSM in the era of contemporary systemic treatment. ROC curve showed that the 8th pathological prognostic staging had better discriminative ability compared with the 7th anatomical staging [the area under the curve (AUC) 0.653 vs. 0.546, P < 0.001]. In the anatomical staging system, PMRT had comparable 5-year BCSS in comparison with non-PMRT both in stages IIA (97.4% vs. 96.8%, P = 0.799) and IIB (95.3% vs. 97.0%, P = 0.071). When stratified according to the pathological staging, PMRT was associated with better 5-year BCSS in stage IIB (97.1% vs. 90.7%, P = 0.039), while not in stages IA, IB, IIA, and IIIA. Multivariate analysis demonstrated that PMRT was a significantly protective factor for BCSS in stage IIB (HR 0.331, 95% CI: 0.100-0.967, P = 0.044).

Conclusion

The new staging could better select high-risk patients with T1-2N1 breast cancer for radiotherapy compared with the 7th staging, and PMRT might be exempted except the 8th staging of IIB in the era of contemporary systemic therapy in this disease.

Influence of age as a continuous variable on the prognosis of patients with pT1-2N1 breast cancer

PURPOSE

To assess the influence of age as a continuous variable on the prognosis of pT1-2N1 breast cancer and examine its decision-making value for postmastectomy radiotherapy (PMRT).

METHODS

We retrospectively evaluated 5438 patients with pT1-2N1 breast cancer after mastectomy in 11 hospitals. A multivariable Cox proportional hazards regression model with penalized splines was used to examine the relationship between age and oncologic outcomes.

RESULTS

The median follow-up was 67.0 months. After adjustments for confounding characteristics, nonsignificant downward trend in locoregional recurrence (LRR) risk was observed with increasing age (P-non-linear association = 0.640; P-linear association = 0.078). A significant non-linear association was found between age and disease-free survival (DFS) and overall survival (OS) (P-non-linear association <0.05; P-linear association >0.05, respectively). The DFS and OS exhibited U-shaped relationships, with the hazard ratios (HRs), reaching a nadir at 50 years old. A decreased risk of LRR with PMRT vs. no PMRT (HR = 0.304, 95% CI: 0.204-0.454) was maintained in all ages. The HR of PMRT vs. no PMRT for DFS and OS gradually increased with age. In patients ≤50 years old, PMRT was independently associated with favorable LRR, DFS, and OS, all P < 0.05). In patients >50 years old, PMRT was independently associated with reduced LRR (P = 0.004), but had no effect on DFS or OS.

CONCLUSIONS

Age was an independent prognostic factor for pT1-2N1 breast cancer; PMRT provided survival benefits for patients ≤50 years old, but not for patients >50 years old.

Postmastectomy Radiation Therapy in Patients With Minimally Involved Lymph Nodes: A Review of the Current Data and Future Directions

Radiation therapy for patients with pN1mi or pN1 disease breast cancer undergoing mastectomy has been debated for a long time. Even in low metastatic burden in sentinel node biopsy, occult non-sentinel axillary nodal involvement can exist. Radiotherapy can sterilize axillary metastatic burden and seems to contribute a very low local recurrence rate in mastectomy patients with minimally involved lymph nodes. However, it should be considered that systemic therapy is evolving and the local recurrence difference between radiotherapy and no radiotherapy is relatively small. Regarding postmastectomy radiotherapy in patients pN1mi or pN1 cancer, published prospective clinical trial results should be considered; however, there are no such relevant results of clinical trials yet. Consideration of postmastectomy radiation therapy in pN1mi or pN1 patients should be based on identifying the high-risk group in terms of recurrence, stage, or tumor biology. When radiotherapy is determined, radiation oncologists should attempt individualized treatment approaches, such as irradiation field, and consider specific settings, such as neoadjuvant therapy. In this review, the role of radiotherapy in mastectomy patients with minimally involved lymph nodes and the relevant considerations are discussed.

POstmastectomy radioThErapy in Node-posiTive breast cancer with or without Internal mAmmary nodaL irradiation (POTENTIAL): a study protocol for a multicenter prospective phase III randomized controlled trial

BACKGROUND

Various randomized trials have demonstrated that postmastectomy radiotherapy (RT) to the chest wall and comprehensive regional nodal areas improves survival in patients with axillary node-positive breast cancer. Controversy exists as to whether the internal mammary node (IMN) region is an essential component of regional nodal irradiation. Available data on the survival benefit of IMN irradiation (IMNI) are conflicting. The patient populations enrolled in previous studies were heterogeneous and most studies were conducted before modern systemic treatment and three-dimensional (3D) radiotherapy (RT) techniques were introduced. This study aims to assess the efficacy and safety of IMNI in the context of modern systemic treatment and computed tomography (CT)-based RT planning techniques.

METHODS

POTENTIAL is a prospective, multicenter, open-label, parallel, phase III, randomized controlled trial investigating whether IMNI improves disease-free survival (DFS) in high-risk breast cancer with positive axillary nodes (pN+) after mastectomy. A total of 1800 patients will be randomly assigned in a 1:1 ratio to receive IMNI or not. All patients are required to receive ≥ six cycles of anthracycline and/or taxane-based chemotherapy. Randomization will be stratified by institution, tumor location (medial/central vs. other quadrants), the number of positive axillary nodes (1-3 vs. 4-9 vs. ≥10), and neoadjuvant chemotherapy (yes vs. no). Treatment will be delivered with CT-based 3D RT techniques, including 3D conformal RT, intensity-modulated RT, or volumetric modulated arc therapy. The prescribed dose is 50 Gy in 25 fractions or 43.5 Gy in 15 fractions. Tiered RT quality assurance is required. After RT, patients will be followed up at regular intervals. Oncological and toxilogical outcomes, especially cardiac toxicities, will be assessed.

DISCUSSION

This trial design is intended to overcome the limitations of previous prospective studies by recruiting patients with pN+ breast cancer, using DFS as the primary endpoint, and prospectively assessing cardiac toxicities and requiring RT quality assurance. The results of this study will provide high-level evidence for elective IMNI in patients with breast cancer after mastectomy.

TRIAL REGISTRATION

ClinicalTrails.gov , NCT04320979 . Registered 25 Match 2020, https://clinicaltrials.gov/ct2/show/NCT04320979.

Postmastectomy radiotherapy: a review

PURPOSE OF REVIEW

We review the role of postmastectomy radiotherapy (PMRT) in the management of patients with early breast cancer.

RECENT FINDINGS

PMRT in patients with 4 or more involved axillary lymph nodes is the current standard of care but the indications for PMRT in patients with 1-3 involved nodes remain controversial. The Early Breast Cancer Trialists' Collaborative Group meta-analysis of randomised trials of PMRT provides the most comprehensive level 1 evidence base. However, its applicability in contemporary practice in the context of recent multidisciplinary advances in surgery, radiation therapy and systemic therapy remains challenging.

SUMMARY

The lack of consensus on the indications for PMRT in patients with 1-3 positive nodes underpins the variations in the national and international guidelines on PMRT. We emphasise the need for contemporary randomised trial data, and the potential to refine patient selection for PMRT using novel biomarkers of recurrence and radiosensitivity.

Debate: Postmastectomy Radiation Therapy in T1/2N1 Disease

Although postmastectomy radiation therapy is known to reduce local recurrence in patients with T1/2N1 breast cancer, some have postulated that not all patients require this treatment. In this era of genomic analyses and personalized therapy, clinicians have debated whether the toxicity of post-mastectomy radiation therapy (PMRT) can be avoided for some subsets of patients. However, the data in this regard remain controversial, particularly as surgeons de-escalate the surgical management of the axilla. Several ongoing clinical trials may provide a glimpse into optimal management in this scenario. However, the "right" answer to this debate currently remains unclear.

Postmastectomy radiotherapy for all node positive patients: The case against

Postmastectomy radiotherapy (PMRT) is accepted as the standard of care for women with early breast cancer with 4 or more involved axillary nodes. However the role of PMRT in women with 1-3 involved nodes remains controversial and guidelines vary. We present the arguments against advocating postmastectomy radiotherapy for all women with node positive breast cancer.