Clinicopathological features of male patients with breast cancer based on a nationwide registry database in Japan

Akihiko Shimomura, Masayuki Nagahashi, Hiraku Kumamaru, Kenjiro Aogi, Sota Asaga, Naoki Hayashi, Kotaro Iijima, Takayuki Kadoya, Yasuyuki Kojima, Makoto Kubo, Minoru Miyashita, Hiroaki Miyata, Naoki Niikura, Etsuyo Ogo, Kenji Tamura, Kenta Tanakura, Masayuki Yoshida, Yutaka Yamamoto, Shigeru Imoto, Hiromitsu Jinno

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Background: Male breast cancer (MBC) is rare; however, its incidence is increasing. There have been no large-scale reports on the clinicopathological characteristics of MBC in Japan. Methods: We investigated patients diagnosed with breast cancer in the Japanese National Clinical Database (NCD) between January 2012 and December 2018. Results: A total of 594,316 cases of breast cancer, including 3780 MBC (0.6%) and 590,536 female breast cancer (FBC) (99.4%), were evaluated. The median age at MBC and FBC diagnosis was 71 (45–86, 5–95%) and 60 years (39–83) (p < 0.001), respectively. MBC cases had a higher clinical stage than FBC cases: 7.4 vs. 13.3% stage 0, 37.2 vs. 44.3% stage I, 25.6 vs. 23.9% stage IIA, 8.8 vs. 8.4% stage IIB, 1.9 vs. 2.4% stage IIIA, 10.1 vs. 3.3% stage IIIB, and 1.1 vs. 1.3% stage IIIC (p < 0.001). Breast-conserving surgery was more frequent in FBC (14.6 vs. 46.7%, p = 0.02). Axillary lymph node dissection was more frequent in MBC cases (32.9 vs. 25.2%, p < 0.001). Estrogen receptor(ER)-positive disease was observed in 95.6% of MBC and 85.3% of FBC cases (p < 0.001). The HER2-positive disease rates were 9.5% and 15.7%, respectively (p < 0.001). Comorbidities were more frequent in MBC (57.3 vs. 32.8%) (p < 0.001). Chemotherapy was less common in MBC, while endocrine therapy use was similar in ER-positive MBC and FBC. Perioperative radiation therapy was performed in 14.3% and 44.3% of cases. Conclusion: Japanese MBC had an older age of onset, were more likely to be hormone receptor-positive disease, and received less perioperative chemotherapy than FBC.

Original languageEnglish
Pages (from-to)985-992
Number of pages8
JournalBreast Cancer
Issue number6
Publication statusPublished - 2022 Nov


  • Japanese
  • Male breast cancer
  • National clinical database

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Pharmacology (medical)


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