title: Young adult breast cancer patients have a poor prognosis independent of prognostic clinicopathological factors: a study from the Japanese Breast Cancer Registry.
abstract: The aim of this study was to investigate whether young age at onset of breast cancer is an independent prognostic factor in patients from the Japanese Breast Cancer Registry, after adjustment of known clinicopathological prognostic factors.
  
  
  
  Of the 53,670 patients registered between 2004 and 2006 and surveyed after a 5-year follow-up prognosis, 25,898 breast cancer patients (48.3 %), who were obtained prognostic data, were examined. Clinicopathological factors were compared between young adult (YA; <35 years), middle-aged adult (MA; 35-50 years), and older adult (OA; >50 years) patients. Five-year disease-free survival (DFS) and overall survival (OS) rates were studied.
  
  
  
  YA patients were associated with an advanced TNM stage and aggressive characteristics (e.g. human epidermal growth factor receptor 2 (HER2)-positive or oestrogen receptor (ER)-negative breast cancers) compared to MA and OA patients (P < 0.001). The 5-year DFS and OS rates were 79.4 % and 90.8, 88.5 and 95.0 %, and 87.8 % and 91.6 % for YA, MA, and OA patients, respectively. From the multivariable regression analysis, young age at onset was confirmed as an independent prognostic factor for both DFS (hazard ratio 1.73, 95 % confidence interval 1.42-2.10; P < 0.001) and OS (hazard ratio 1.58, 95 % confidence interval 1.16-2.15; P = 0.004).
  
  
  
  Young age at onset is an independent negative prognostic factor in breast cancer. Further studies are required to develop new therapeutic strategies for YA breast cancer patients.
authors.affiliation: Breast Surgical Oncology Department, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo, Japan.
authors.forename: Akemi
authors.initials: A
authors.lastname: Kataoka
authors.affiliation: Department of Breast and Endocrine Surgery, Okayama University Hospital, 2-5-1 Shikata-cho, Kitaku, Okayama City, Okayama, 700-8558, Japan. tiwamoto@cc.okayama-u.ac.jp.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Iwamoto
authors.affiliation: Department of Breast Oncology, National Hospital Organization Kyushu Cancer Center, Fukuoka, Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Tokunaga
authors.affiliation: Department of Healthcare Quality Assessment, Graduate School of Medicine, Tokyo University, Tokyo, Japan.
authors.forename: Ai
authors.initials: A
authors.lastname: Tomotaki
authors.affiliation: Department of Healthcare Quality Assessment, Graduate School of Medicine, Tokyo University, Tokyo, Japan.
authors.forename: Hiraku
authors.initials: H
authors.lastname: Kumamaru
authors.affiliation: Department of Healthcare Quality Assessment, Graduate School of Medicine, Tokyo University, Tokyo, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Miyata
authors.affiliation: Department of Breast and Endocrine Surgery, Tokai University School of Medicine, Kanagawa, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Niikura
authors.affiliation: Department of Breast Surgery, Miyagi Cancer Center, Natori, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kawai
authors.affiliation: Department of Surgery, Kitakyushu Municipal Medical Center, Kitakyushu, Japan.
authors.forename: Keisei
authors.initials: K
authors.lastname: Anan
authors.affiliation: Department of Breast Surgery, St. Luke's International Hospital, Tokyo, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Hayashi
authors.affiliation: Department of Pathology, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Masuda
authors.affiliation: Division of Breast and Endocrine Surgery, Department of Surgery, St. Marianna University School of Medicine, Kawasaki, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Tsugawa
authors.affiliation: Department of Breast Surgery, Shikoku Cancer Center, Matsuyama, Japan.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Aogi
authors.affiliation: Department of Surgical Oncology, Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Ishida
authors.affiliation: Sapporo-kotoni Breast Clinic, Sapporo, Japan.
authors.forename: Hideji
authors.initials: H
authors.lastname: Masuoka
authors.affiliation: Department of Breast Oncology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Iijima
authors.affiliation: Department of Breast Surgery, National Cancer Center Hospital, Tokyo, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kinoshita
authors.affiliation: Division of Breast Surgical Oncology, Department of Surgery, Showa University, Tokyo, Japan.
authors.forename: Seigo
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Department of Breast and Endocrine Surgery, Tokai University School of Medicine, Kanagawa, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Tokuda
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000453:epidemiology / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007564:Japan / Q000453:epidemiology; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011159:Population Surveillance; D011379:Prognosis; D016016:Proportional Hazards Models; D012042:Registries; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor
keywords: Breast cancer; Multivariable analysis; Prognosis; Surveillance data; Young women