Risk factors for locoregional recurrence after postmastectomy radiotherapy in breast cancer patients with four or more positive axillary lymph nodes

Residual fibroglandular breast tissue after mastectomy is associated with an increased risk of a local recurrence or a new primary breast cancer"

BACKGROUND

Residual fibroglandular breast tissue (RFGT) following a mastectomy has been claimed to be associated with the occurrence of an in-breast local recurrence (IBLR) or new primary tumor (NP). Yet, scientific evidence proving this assumption is lacking. The primary aim of the study was to verify whether RFGT following a mastectomy is a risk factor for an IBLR or NP.

METHODS

This retrospective analysis included all patients that underwent a mastectomy and were followed up at the Department of Obstetrics and Gynecology of the Medical University of Vienna between 01.01.2015 and 26.02.2020. RFGT volume (assessed on magnetic resonance imaging) was correlated with the prevalence of an IBLR and a NP.

RESULTS

A total of 105 patients (126 breasts) following a therapeutic mastectomy were included. After a mean follow-up of 46.0 months an IBLR had occurred in 17 breasts and a NP in 1 breast. A significant difference in RFGT volume was observed between the disease-free cohort and the subgroup with an IBLR or NP (p = .017). A RFGT volume of ≥ 1153 mm³ increased the risk by the factor 3.57 [95%CI 1.27; 10.03].

CONCLUSIONS

RFGT volume is associated with an increased risk for an IBLR or NP.

The effectiveness of radiotherapy in preventing disease recurrence after breast cancer surgery

BACKGROUND AND OBJECTIVES

The locoregional management of breast cancer has a critical impact on prognosis. This study aimed to analyze the effectiveness of radiotherapy against the deleterious effect of positive surgical margins on disease outcomes.

METHODS

Retrospective, single-center study enrolled 721 breast cancer patients with a median follow-up of approximately 64.50 months (3.67-247.40). Analyses were performed considering the end of adjuvant therapy, except endocrine therapy. Kaplan-Meier and Cox regression were performed to obtain the predictive value of treatments.

RESULTS

The minimally adequate radiotherapy (≥45 cGy) was associated with improved outcomes in breast cancer patients compared to inadequate radiotherapy (<45 cGy/no) by controlling locoregional relapses and distant metastasis. In patients with positive surgical margins (n = 53), radiotherapy was associated with an approximate decrease of 90% in locoregional relapse risk [adjusted HR: 0.108 (0.012-0.932), p = 0.043]. Radiotherapy did not alter the adverse effect of positive surgical margins, especially in patients with a higher risk of poorly differentiated tumors (n = 146), presence of lymphovascular invasion (n = 163), and triple-negative subtype (n = 113). Notwithstanding, radiotherapy was associated with respective decreases of distant metastasis risk of 75.2% [adjusted HR: 0.248 (0.081-0.762), p = 0.015] and 67.8% [adjusted HR: 0.322 (0.101-1.029), p = 0.056] in patients with triple-negative tumors or with lymphovascular invasion.

CONCLUSION

Adequate radiotherapy is associated with better outcomes in breast cancer. Despite improving locoregional relapse-free survival, radiotherapy does not ablate positive surgical margins, a factor of poorer prognosis that prevails mainly in patients with factors of higher relapse risk.

Cost-effectiveness of postmastectomy hypofractionated radiation therapy vs conventional fractionated radiation therapy for high-risk breast cancer

Background

The phase 3 NCT00793962 trial demonstrated that postmastectomy hypofractionated radiation therapy (HFRT) was noninferior to conventional fractionated radiation therapy (CFRT) in patients with high-risk breast cancer. This study assessed the cost-effectiveness of postmastectomy HFRT vs CFRT based on the NCT00793962 trial.

Methods

A Markov model was adopted to synthesize the medical costs and health benefits of patients with high-risk breast cancer based on data from the NCT00793962 trial. Main outcomes were discounted lifetime costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER). We employed a time-dependent horizon from Chinese, French and USA payer perspectives. Model robustness was evaluated with one-way and probabilistic sensitivity analyses.

Results

Patients receiving CFRT versus HFRT gained an incremental 0.0163 QALYs, 0.0118 QALYs and 0.0028 QALYs; meanwhile an incremental cost of $2351.92, $4978.34 and $8812.70 from Chinese, French and USA payer perspectives, respectively. Thus CFRT versus HFRT yielded an ICER of $144,281.47, $420,636.10 and $3,187,955.76 per QALY from Chinese, French and USA payer perspectives, respectively. HFRT could maintain a trend of >50% probabilities of cost-effectiveness below a willingness-to-pay (WTP) of $178,882.00 in China, while HFRT was dominant relative to CFRT, regardless of the WTP values in France and the USA. Sensitivity analyses indicated that the ICERs were most sensitive to the parameters of overall survival after radiotherapy.

Conclusions

Postmastectomy HFRT could be used as a cost-effective substitute for CFRT in patients with high-risk breast cancer and should be considered in appropriately selected patients.

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HFRT is a cost-effective substitute for CFRT for women with high-risk breast cancer.

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The incremental cost-effectiveness ratio varied in a time-dependent manner and increased with the time horizon.

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Overall survival were the most influential parameter on the incremental cost-effectiveness ratio.

Post-mastectomy radiation therapy in breast cancer patients with 1-3 positive lymph nodes: No one size fits all

Post-mastectomy radiation therapy (PMRT) is standard therapy for advanced breast cancer. However, given the lower risk of recurrence, PMRT administration remains controversial in select patients with limited nodal disease. We performed a review of the literature that focuses on the effect of PMRT in breast cancer patients with 1-3 positive lymph nodes, mainly examining loco-regional recurrence (LRR) and overall survival (OS). Most studies, including a large meta-analysis by the EBCTCG, showed a significant improvement in LRR rates among patients receiving PMRT. While most studies demonstrated a trend towards OS improvement, only few studies showed a statistically significant OS or breast cancer-specific survival benefit for PMRT. As such, individualized treatment decisions are recommended, taking into consideration clinicopathological findings. Future studies with large sample sizes and long follow-up times are still needed to better assess the role of PMRT in patients with limited nodal involvement.

Risk factors and a predictive nomogram for non-sentinel lymph node metastases in Chinese breast cancer patients with one or two sentinel lymph node macrometastases and mastectomy

Background

Two ongoing prospective randomized trials are evaluating whether omitting axillary lymph node dissection (alnd) in patients with breast cancer (bca) and sentinel lymph node (sln) macrometastases undergoing mastectomy is safe. Determining predictive risk factors for non-sln metastases and developing a model to predict the probability of those patients having non-sln metastases is also important.

Methods

This retrospective study enrolled 396 patients with bca and 1-2 slns with macrometastases who underwent alnd and mastectomy between January 2012 and December 2016. Factors influencing the non-sln metastases were determined, and a predictive nomogram was formulated. Performance of the nomogram was evaluated by its area under the curve (auc).

Results

We developed a predictive nomogram with an auc of 0.81 (cross-validation 95% confidence interval: 0.75 to 0.86) that included 4 factors (tumour size, histologic grade, and number of negative slns and axillary lymph nodes on imaging).

Conclusions

Our predictive nomogram assesses the risk of non-sln metastases in patients with bca and 1-2 sln macrometastases undergoing mastectomy.

Should all breast cancer patients with four or more positive lymph nodes who underwent modified radical mastectomy be treated with postoperative radiotherapy? A population-based study

Postmastectomy radiotherapy (PMRT) has become a standard adjuvant postoperative therapy for breast cancer patients with four or more positive lymph nodes. However, some studies have demonstrated that some subgroups of the breast cancer patients with four or more positive lymph nodes did not benefit substantially from PMRT. Therefore, it is of great necessity to identify whether all breast cancer patients with four or more positive lymph nodes who underwent modified radical mastectomy be treated with PMRT. In our study, we first established a prognostic model using the Surveillance Epidemiology and End Results (SEER) database between 1998 and 2001. Univariate and multivariate Cox models were used to assess the prognostic factors, and five risk factors individually associated with prognosis including AJCC stage, AJCC T, Grade, ER status, PR status. Prognostic index of PMRT were defined as the number of risk factor (NRF). The NRF scores correlated well with overall survival of PMRT even if the patients were in the sub-poor prognosis group. Then the prognostic model was validated using the SEER database between 2006 and 2009, and the same results were obtained. In conclusion, different from others studies, our study demonstrated that all patients with four or more positive lymph nodes after modified radical mastectomy need to be treated with PMRT ever if the patients belonged to AJCC T4 in a poor prognosis group.

Regional Nodal Irradiation After Breast Conserving Surgery for Early HER2-Positive Breast Cancer: Results of a Subanalysis From the ALTTO Trial

Background

Two randomized trials recently demonstrated that regional nodal irradiation (RNI) could reduce the risk of recurrence in early breast cancer; however, these trials were conducted in the pretrastuzumab era. Whether these results are applicable to human epidermal growth factor receptor 2 (HER2)-positive breast cancer patients treated with anti-HER2-targeted therapy is unknown.

Methods

This retrospective analysis was performed on patients with node-positive breast cancer who were enrolled in the Adjuvant Lapatinib and/or Trastuzumab Treatment Optimization phase III adjuvant trial and subjected to BCS. The primary objective of the present study was to examine the effect of RNI on disease-free survival (DFS). A multivariable cox regression analysis adjusted for number of positive lymph nodes, tumor size, grade, age, hormone receptors status, presence of macrometastatis, treatment arm, and chemotherapy timing was carried out to investigate the relationship between RNI and DFS.

Results

One thousand six hundred sixty-four HER2-positive breast cancer patients were included, of whom 878 (52.8%) had received RNI to the axillary, supraclavicular, and/or internal mammary lymph nodes. Patients in the RNI group had higher nodal burden and more frequently had tumors larger than 2 cm. At a median follow-up of 4.5 years, DFS was 84.3% in the RNI group and 88.3% in the non-RNI group. No differences in regional recurrence (0.9 % vs 0.6 %) or in overall survival (93.6% vs 95.3%) were observed between the two groups. After adjustment in multivariable analysis, there was no statistically significant association between RNI and DFS (hazard ratio = 0.96, 95% confidence interval = 0.71 to 1.29).

Conclusions

Our analysis did not demonstrate a DFS benefit of RNI in HER2-positive, node-positive patients treated with adjuvant HER2-targeted therapy. The benefit of RNI in HER2-positive breast cancer needs further testing within randomized clinical trials.