Outcomes in Patients with pT3N0M0 Breast Cancer with and without Postmastectomy Radiotherapy

Abstract

Purpose

The role of adjuvant postmastectomy radiotherapy (PMRT) remains controversial for patients with pT3N0M0 breast cancer, especially when patients are treated with the updated adjuvant chemotherapy. Our study aimed to compare locoregional recurrence-free survival (LRFS), disease-free survival (DFS), and breast cancer-specific survival (BCSS) in pT3N0M0 patients with and without postmastectomy radiotherapy.

Patients and Methods

Between October 2000 and 8 September 2016, the database of the Breast Cancer Center of Shanghai yielded 114 patients with node-negative non-metastatic breast cancer larger than 5 cm. Univariate and multivariate analyses were performed to assess the risk factors for survivals. Differences between the two groups were compared using the Log rank test.

Results

Fifty-nine (51.8%) of the patients received adjuvant PMRT. The median follow-up was 62.3 months. Five-year LRFS was 100% in the PMRT group vs 98.1% in the non-PMRT group (P=0.17); 5-year DFS was 97.1% for the entire cohort, 98.0% for the PMRT group vs 96.2% for the non-PMRT group (P=0.18). Univariate analysis identified that family history of malignant tumors, lymphovascular invasion (LVI), or triple-negative breast cancer (TNBC) molecular subtype were associated with higher locoregional recurrence (LRR) (P<0.05). No PMRT was the only risk factor independently associated with poorer DFS (P=0.048) on multivariate analysis. No difference in BCSS was observed between the two groups.

Conclusion

The present study demonstrated a low LRR rate and good survival for node-negative breast cancer >5 cm. Patients with family history of malignant tumors, TNBC subtype, LVI positivity, or grade 3 disease are at high risk for LRR and might benefit from PMRT.

Keywords:

• node-negative
• updated systemic treatment
• radiotherapy
• locoregional recurrence

Acknowledgments

We thank H. Nikki March, PhD, from Liwen Bianji, Edanz Editing China ( www.liwenbianji.cn/ac ), for editing the English text of a draft of this manuscript.

Abbreviations

ALND, axillary lymph node dissection; BCSS, breast cancer-specific survival; DFS, disease-free survival; DM, distant metastasis; EBCTCG, Early Breast Cancer Trialists’ Collaborative Group; ER, estrogen receptor; HER2, human epithelial growth factor receptor-2; HT, hormonal therapy; IDC, invasive ductal carcinoma; LRFS, locoregional recurrence-free survival; LRR, locoregional recurrence; LVI, lymphovascular invasion; NCCN, National Comprehensive Cancer Network; OS, overall survival; PMRT, postmastectomy radiotherapy; PR, progesterone receptor; SEER, Surveillance, Epidemiology, and End Results; TNBC, triple-negative breast cancer.

Data Sharing Statement

The data that support the findings of this study are available from the patient records of the Fudan University Shanghai Cancer Center, Shanghai, China; but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data are however available from the authors upon reasonable request and with permission of the Fudan University Shanghai Cancer Center, Shanghai, China.

Ethics Approval and Informed Consent

Ethics approval for this study was obtained from the Ethic Committee Office of Fudan University Shanghai Cancer center, the reference numbers are 1807188-4. The database complies with relevant data protection and privacy regulations, and that this study was conducted in accordance with the Declaration of Helsinki.

Consent for Publication

This manuscript is approved by all authors for publication. The work described was original research that has not been published previously, and not under consideration for publication elsewhere, in whole or in part. All the authors listed have approved the manuscript that is enclosed.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.