Prognostic impact of postoperative radiotherapy in patients with breast cancer and with pT1-2 and 1–3 lymph node metastases: A retrospective cohort study based on the Japanese Breast Cancer Registry

Akimitsu Yamada, Naoki Hayashi, Hiraku Kumamaru, Masayuki Nagahashi, Shiori Usune, Sota Asaga, Kotaro Iijima, Takayuki Kadoya, Yasuyuki Kojima, Makoto Kubo, Minoru Miyashita, Hiroaki Miyata, Etsuko Ogo, Kenji Tamura, Kenta Tanakura, Keiichiro Tada, Naoki Niikura, Masayuki Yoshida, Shinji Ohno, Takashi IshikawaKazutaka Narui, Itaru Endo, Shigeru Imoto, Hiromitsu Jinno

Research output: Contribution to journalArticlepeer-review

Abstract

Aim: Postmastectomy radiotherapy (PMRT) is the standard treatment for locally advanced breast cancer. However, the effectiveness of PMRT in patients with pT1-2 and N1 tumours remains controversial. Therefore, this study aimed to determine the prognostic impact of PMRT in patients with breast cancer and with pT1-2 and 1–3 lymph node metastases. Methods: Using data from the Japanese National Clinical Database from 2004 to 2012, we evaluated the association of PMRT with locoregional recurrence (LRR), any recurrence, and mortality. We enrolled patients who had undergone mastectomy and axillary node dissection and were diagnosed with pT1-2 and N1. We compared clinicopathological factors and prognosis between patients who received (PMRT group) and those who did not receive (No-PMRT group) PMRT. Results: Among 8914 patients enrolled, 492 patients belonged to the PMRT group and 8422 to the No-PMRT group. The median observation time was 6.3 years. There was no significant difference in the incidences of LRR (4.0% versus 5.0%, P = 0.61), recurrence (13.8% versus 11.8%, P = 0.23) and breast cancer death (6.0% versus 4.3%, P = 0.08) at 5 years between the groups. Multivariable analysis revealed that LRR was significantly associated with tumour size, number of node metastases and triple-negative subtype but not with PMRT. Conclusions: The LRR rate in the No-PMRT group was 5.0% at 5 years among patients with T1-2 and N1. PMRT did not significantly influence LRR in patients with T1-2 and N1. However, PMRT administration should be tailored considering the individual risks of tumour size, 3 node metastases and triple-negative subtype.

Original languageEnglish
Pages (from-to)31-40
Number of pages10
JournalEuropean Journal of Cancer
Volume172
DOIs
Publication statusPublished - 2022 Sep
Externally publishedYes

Keywords

  • Breast cancer
  • Database
  • Japan
  • Mastectomy
  • Radiotherapy
  • Recurrence
  • Survival

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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