title: Distinct breast cancer characteristics between screen- and self-detected breast cancers recorded in the Japanese Breast Cancer Registry.
abstract: The rate of breast cancer screening for women of all ages in Japan is increasing. However, little is known about the biological differences between screen- and self-detected tumors. We used data from the Japanese Breast Cancer Registry (JBCR), a nationwide registry of newly diagnosed breast cancer cases in Japan, to investigate patients diagnosed between January 1, 2004 and December 31, 2011. We compared the clinicopathological features of tumors and assessed yearly trends regarding the proportion of screen-detected cases during the study period. We found that 31.8 % (65,358/205,544) of cancers were detected by screening. Asymptomatic tumors detected by screening (asymptomatic) were more likely to have favorable prognostic features than those that were self-detected (ductal carcinoma in situ [DCIS]: 19.8 versus 4.1 %, node-negative: 77.0 versus 61.6 %, and estrogen receptor-positive [ER+]: 82.0 versus 72.9 %, respectively). All these findings were statistically significant (p < .001). The proportion of breast cancers detected by screening among all cases increased from 21.7 % in 2004 to 37.1 % in 2011. During the same time period, the proportion of screen-detected DCIS increased from 41.5 to 66.0 % and that of ER+ cancers increased from 23.2 to 39.7 %. This study demonstrated that low-risk tumors, including DCIS, ER+, and lower TNM stage, account for a substantial proportion of clinical screening-detected cancers. The differences in biological characteristics between screen- and self-detected cancers may account in part for the limited efficacy of breast cancer screening programs aimed at improving breast cancer mortality.
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 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 Healthcare Quality Assessment, Graduate School of Medicine, Tokyo University, Tokyo, Japan.
authors.forename: Ai
authors.initials: A
authors.lastname: Tomotaki
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, Cancer Institute Hospital, Tokyo, Japan.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Iijima
authors.affiliation: Department of Palliative and Supportive Medicine, Okayama University Hospital, Okayama, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Matsuoka
authors.affiliation: Department of Breast and Endocrine Surgery, Okayama University Hospital, 2-5-1 Shikata-cho, Kitaku, Okayama City, Okayama, 700-8558, Japan.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Doihara
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: D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000175:diagnosis* / Q000378:metabolism; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D006801:Humans; D007564:Japan; D008403:Mass Screening / Q000706:statistics & numerical data / Q000639:trends*; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D012042:Registries
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human
keywords: DCIS; Estrogen receptor; Japanese Breast Cancer Registry; Screening; Yearly trend