title: Postoperative elevation of CA15-3 due to pernicious anemia in a patient without evidence of breast cancer recurrence.
abstract: Cancer antigen 15-3 (CA15-3) is considered as a marker for breast cancer recurrence. However, we encountered a case where the patient showed postoperative elevation of the CA15-3 level due to pernicious anemia without evidence of breast cancer recurrence. The patient was a 60-year-old postmenopausal woman. She had undergone partial mastectomy and sentinel lymph node biopsy (SLNB) for her T1 left breast cancer. SLNB had indicated no lymph node metastases. The tumor was positive for hormone receptors and negative for human epidermal growth factor receptor 2. Therefore, an aromatase inhibitor and external beam irradiation had been administered as adjuvant therapy. However, the CA15-3 level was found to be elevated at 6 months postoperatively. Although imaging studies did not indicate breast cancer recurrence, CA15-3 levels continued to increase. Based on the findings of blood tests and gastroendoscopy, a diagnosis of pernicious anemia due to vitamin B12 deficiency was finally confirmed at 2 years and 6 months postoperatively. The CA15-3 level returned to normal after vitamin B12 administration. The possibility of pernicious anemia should be considered in cases of postoperative elevated CA15-3 levels with no evidence of recurrence in patients with early breast cancer.
authors.affiliation: Department of Transplantation and Endocrine Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya, Aichi, 466-8560, Japan. adachiy@med.nagoya-u.ac.jp.
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Adachi
authors.affiliation: Department of Transplantation and Endocrine Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya, Aichi, 466-8560, Japan. kikumori@med.nagoya-u.ac.jp.
authors.forename: Toyone
authors.initials: T
authors.lastname: Kikumori
authors.affiliation: Department of Transplantation and Endocrine Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya, Aichi, 466-8560, Japan. miyajima@med.nagoya-u.ac.jp.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Miyajima
authors.affiliation: Department of Transplantation and Endocrine Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya, Aichi, 466-8560, Japan. t.inaishi@med.nagoya-u.ac.jp.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Inaishi
authors.affiliation: Department of Transplantation and Endocrine Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya, Aichi, 466-8560, Japan. eiji.onishi.17@med.nagoya-u.ac.jp.
authors.forename: Eiji
authors.initials: E
authors.lastname: Onishi
authors.affiliation: Department of Transplantation and Endocrine Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya, Aichi, 466-8560, Japan. m-shibata@med.nagoya-u.ac.jp.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shibata
authors.affiliation: Department of Transplantation and Endocrine Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya, Aichi, 466-8560, Japan. nishikensurg@med.nagoya-u.ac.jp.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Nakanishi
authors.affiliation: Department of Transplantation and Endocrine Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya, Aichi, 466-8560, Japan. daitakeushi@med.nagoya-u.ac.jp.
authors.forename: Dai
authors.initials: D
authors.lastname: Takeuchi
authors.affiliation: Department of Transplantation and Endocrine Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya, Aichi, 466-8560, Japan. hhayashi@med.nagoya-u.ac.jp.
authors.forename: Hironori
authors.initials: H
authors.lastname: Hayashi
authors.affiliation: Department of Gastroenterological Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa, Nagoya, Aichi, 466-8560, Japan. ykodera@med.nagoya-u.ac.jp.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kodera
keywords: Breast cancer; CA15-3; Pernicious anemia