Role of Postmastectomy Radiotherapy After Neoadjuvant Chemotherapy in Breast Cancer Patients: A Study from the Japanese Breast Cancer Registry

Minoru Miyashita, Naoki Niikura, Hiraku Kumamaru, Hiroaki Miyata, Takayuki Iwamoto, Masaaki Kawai, Keisei Anan, Naoki Hayashi, Kenjiro Aogi, Takanori Ishida, Hideji Masuoka, Kotaro Iijima, Shinobu Masuda, Koichiro Tsugawa, Takayuki Kinoshita, Hitoshi Tsuda, Seigo Nakamura, Yutaka Tokuda

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1 Citation (Scopus)

Abstract

Background: The role of postmastectomy radiotherapy (PMRT) in breast cancer patients receiving neoadjuvant chemotherapy (NAC) is controversial. We aimed to evaluate the effectiveness of radiotherapy in patients treated with NAC and mastectomy in the Japanese Breast Cancer Registry. Methods: We enrolled patients who received NAC and mastectomy for cT1–4 cN0–2 M0 breast cancer. We evaluated the association between radiotherapy and outcomes, locoregional recurrence (LRR), distant disease-free survival (DDFS), and overall survival (OS) based on ypN status by multivariable analysis. Results: Of the 145,530 patients, we identified 3226 who met the inclusion criteria. Among ypN1 patients, no differences were found in LRR, DDFS, or OS between groups with and without radiotherapy (p = 0.72, p = 0.29, and p = 0.36, respectively). Radiotherapy was associated with improved LRR-free survival (p < 0.001), DDFS (p = 0.01), and OS (p < 0.001) in patients with ypN2–3. Multivariable analysis demonstrated that use of radiotherapy was independently associated with improved LRR [hazard ratio (HR) 0.61, 95% confidence interval (CI) 0.45–0.82, p = 0.001] and OS [HR 0.69, 95% CI 0.53–0.89, p = 0.004) for ypN2–3 patients only. The association between radiotherapy and OS was not statistically significant among ypN0 (p = 0.22) and ypN1 patients (p = 0.51). Conclusions: The results from this nationwide database study did not show significant associations between PMRT and improved survival among ypN0 and ypN1 patients. Radiotherapy may be beneficial only for ypN2–3 breast cancer patients who receive NAC and mastectomy in the modern era.

Original languageEnglish
JournalAnnals of Surgical Oncology
DOIs
Publication statusPublished - Jan 1 2019

ASJC Scopus subject areas

  • Surgery
  • Oncology

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  • Cite this

    Miyashita, M., Niikura, N., Kumamaru, H., Miyata, H., Iwamoto, T., Kawai, M., Anan, K., Hayashi, N., Aogi, K., Ishida, T., Masuoka, H., Iijima, K., Masuda, S., Tsugawa, K., Kinoshita, T., Tsuda, H., Nakamura, S., & Tokuda, Y. (2019). Role of Postmastectomy Radiotherapy After Neoadjuvant Chemotherapy in Breast Cancer Patients: A Study from the Japanese Breast Cancer Registry. Annals of Surgical Oncology. https://doi.org/10.1245/s10434-019-07453-1