The effect of post mastectomy radiation therapy on survival in breast cancer patients with N1mic disease

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

Aim

The 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.

Method

A 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.

Results

In 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).

Conclusion

PMRT 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.

The trade-off of post-mastectomy radiotherapy usage for the breast cancer patients aged 70 years or older: a study based on SEER database

BACKGROUND

This study aimed to investigate the role of post-mastectomy radiotherapy (PMRT) in the female aged 70 years or older diagnosed with breast cancer, which is still controversial.

METHODS

This retrospective study enrolled female breast cancer women aged 70 + years following mastectomy from the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching (PSM) was performed to reduce covariable imbalance. A nomogram was created to predict the 1,3,5-years overall survival (OS) and divide patients into three risk groups.

RESULTS

After matching, PMRT were associated with significant improvement in breast cancer-specific survival (BCSS) and OS (p < 0.001). By contrast, the BCSS and OS benefit from PMRT were not significant in patients with T1N1 tumor (BCSS: HR = 0.716, p = 0.249;OS:HR = 0.908, p = 0.572), and T2N1 tumor (BCSS:HR = 0.866, p = 0.289;OS:HR = 0.879, p = 0.166). Stratified by subtype, the HR+/HER-2- subtype and the HR-/HER-2- subtype (all p < 0.001) have a significant prolonged survival, yet not significant BCSS difference are shown in the HER-2 + tumor. In the low-risk group as determined by the nomogram, the use of PMRT did not significantly improve OS (p = 0.203).

CONCLUSIONS

This study demonstrated that PMRT improves the survival of females with elderly breast cancer, while for T1-2N1 breast cancer patients, the omission of PMRT could be considered. Furthermore, the nomogram we constructed could be used as a decision tool for the omission of PMRT in low-risk elderly patients.

Evaluation of adjuvant therapy for T1-2N1miM0 breast cancer without further axillary lymph node dissection

Background

For breast cancer (BC) with sentinel lymph node micrometastases (SLNMs), there are limited data to guide the selection of postoperative adjuvant therapy. This study aimed to identify target populations who might benefit most from adjuvant therapy and examine prognostic factors among patients with T1-2N1miM0 BC with one or two SLNMs who underwent sentinel lymph node biopsy (SLNB) alone.

Methods

There were 7,423 patients diagnosed with T1-2N1miM0 BC between 2010 and 2015, and patients with one or two SLNMs were extracted from the Surveillance, Epidemiology, and End Results database. All the patients underwent SLNB alone without further axillary lymph node dissection, and they were stratified according to adjuvant therapy. The statistical significance of categorical variables was analyzed using the χ ² test. Univariable and multivariable Cox analyses were used to analyze characteristics predictive of Breast-cancer-specific survival and overall survival (OS). Kaplan-Meier methods with the log-rank test was analyzed to compare survival difference between the different treatments.

Results

Adjuvant chemotherapy and radiotherapy improved 5-year OS rates. Multivariate analysis revealed that age ≥70 years, high grade, T2 stage, triple-negative subtype, and absence of radiotherapy were poor prognostic factors for OS. Patients who received breast-conserving surgery (BCS), and those with invasive ductal carcinoma (IDC), luminal A, luminal B, or basal-like subtype, and T1c or T2 stage benefited from adjuvant radiotherapy. Patients who received BCS, and those with IDC, luminal A subtype, and T1b, T1c, or T2 stage benefited from adjuvant chemotherapy.

Conclusion

Our findings provide a clinical evaluation of treatment choice after surgery, which may help clinicians make individualized clinical decisions.

The Preventive Effects of Boron-Based Gel on Radiation Dermatitis in Patients Being Treated for Breast Cancer: A Phase III Randomized, Double-Blind, Placebo-Controlled Clinical Trial

INTRODUCTION

Radiation dermatitis (RD) is a side effect of radiation therapy (RT) which is experienced by over 90% of patients being treated for breast cancer. The current clinical trial was conducted to measure the preventative effects of a boron-based gel on several different clinical outcomes (dermatitis, erythema, dry desquamation, and moist desquamation) after 25 radiotherapy sessions.

METHODS

This research used a double-blind parallel-group design with a placebo control (n = 76) and randomized group (n = 181), with all participants being between 18 and 75 years old. Fifteen minutes before each radiotherapy, participants in the intervention group were given a gel containing 3% sodium pentaborate pentahydrate, while those in the placebo group received a gel with no chemical substance. Dermatitis, erythema, dry desquamation, and moist desquamation were compared between the 2 groups.

RESULTS

At baseline, there were no significant differences between the groups (p > 0.05), except for body mass index. After 14 days of treatment, dermatitis (98.7% vs. 9.9%; p < 0.001), erythema (96.1% vs. 12.2%; p < 0.001), dry desquamation (50% vs. 3.9%; p < 0.001), and moist desquamation (18.4% vs. 0.6%; p < 0.001) were much more common in the placebo group than the intervention group. To prevent dermatitis, erythema, dry desquamation, and moist desquamation in 1 patient, on average, 1.1 (95% confidence interval [CI]: 1.1-1.2), 1.2 (95% CI: 1.1-1.3), 2.2 (95% CI: 1.7-2.9), and 5.6 (95% CI: 3.8-11.0) patients need to be treated, respectively.

CONCLUSION

The boron-based gel has a significant preventive effect on several categories of RD which might be used by clinicians in breast cancer.

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.

Prognostic and Predictive Value of the American Joint Committee on Cancer Pathological Prognostic Staging System in Nodal Micrometastatic Breast Cancer

Introduction

To investigate the prognostic and predictive effect of the American Joint Committee on Cancer (AJCC) 8^th edition pathological prognostic staging system in patients with T1-2N1micM0 breast cancer who underwent mastectomy.

Methods

Data from T1-2N1micM0 breast cancer patients who underwent mastectomy from 2010–2014 were obtained from the Surveillance, Epidemiology, and End Results program. The chi-square test, binomial logistics regression, receiver-operating characteristics curve, competing-risk regression model, Cox proportional hazards regression model, and proportional hazard assumption were used for statistical analyses.

Results

We identified 4,729 patients, including 1,062 patients were received postmastectomy radiotherapy (PMRT). Stage change occurred in 88.2% of the patients, of which 84.4% were downstaged and 3.7% were upstaged. Patients with higher pathological prognostic stages were independently predicted to receive PMRT. The 5-year breast cancer-specific survival (BCSS) was 97.5, 93.7, 90.1, 86.0, and 73.5% in disease stages IA, IB, IIA, IIB, and IIIA, respectively, according to the 8^th edition criteria (P < 0.001). The AJCC 8^th edition demonstrated moderate discriminative ability, and it had a significantly better ability to predict the BCSS than the AJCC 7^th edition criteria (P < 0.001). The multivariate prognostic analysis showed that the new pathological prognostic staging was an independent prognostic factor affecting the BCSS. The BCSS worsened with an increase in the stage. The PMRT did not affect the BCSS regardless of the pathological prognostic stage. Similar trends were found using the competing-risks regression model.

Conclusions

The 8^th AJCC breast cancer pathological prognostic staging system downstaged 84.4% of patients with T1-2N1micM0 disease and the survival outcome prediction with this staging system was more accurate than the AJCC 7^th edition system. Our study does not support using the prognostic stage as a guideline to escalate of PMRT.