title: Bilateral risk for subsequent breast cancer after lobular carcinoma-in-situ: analysis of surveillance, epidemiology, and end results data.
abstract: OBJECTIVE
  Noninvasive lesions involving the lobules of the breast are increasingly diagnosed as incidental microscopic findings at the time of lumpectomy or core-needle biopsy. We investigated the incidence rates of invasive breast cancer (IBC) after a diagnosis of lobular carcinoma-in-situ (LCIS) by using Surveillance, Epidemiology, and End Results (SEER) data.
  
  
  METHODS
  Patients (N = 4,853) having a diagnosis of primary LCIS in the time period of 1973 to 1998 were identified using the SEER Public Use CD-ROM data. The database was then searched for patients with subsequent primary IBC occurrences (n = 350). The clinical and pathologic characteristics of patients with subsequent primary IBCs were compared with the characteristics of patients with primary IBCs attained during the same time period (N = 255,114).
  
  
  RESULTS
  The incidence of IBC increased over time from diagnosis of LCIS, with 7.1% +/- 0.5% incidence of IBC at 10 years. IBCs detected after partial mastectomy occurred in either breast (46% ipsilateral and 54% contralateral); however, after mastectomy, most IBCs were contralateral (94.7%). IBCs occurring after LCIS more often represented invasive lobular histology (23.1%) compared with primary IBCs (6.5%). The standardized incidence ratio (the ratio of observed to expected cases) for developing IBC was 2.4 (95% CI, 2.1 to 2.6) adjusted for age and year of diagnosis.
  
  
  CONCLUSIONS
  LCIS is associated with increased risk of subsequent invasive disease, with equal predisposition in either breast. The minimum risk of developing IBC after LCIS is 7.1% at 10 years.
authors.affiliation: Department of Radiation Oncology, St John Hospital Van Elslander Cancer Center, Grosse Pointe, MI, USA. paul.chuba@stjohn.org
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Chuba
authors.forename: Merlin R
authors.initials: MR
authors.lastname: Hamre
authors.forename: Johnny
authors.initials: J
authors.lastname: Yap
authors.forename: Richard K
authors.initials: RK
authors.lastname: Severson
authors.forename: David
authors.initials: D
authors.lastname: Lucas
authors.forename: Falah
authors.initials: F
authors.lastname: Shamsa
authors.forename: Amr
authors.initials: A
authors.lastname: Aref
mesh_terms: D001943:Breast Neoplasms / Q000453:epidemiology / Q000473:pathology*; D002278:Carcinoma in Situ / Q000453:epidemiology / Q000473:pathology*; D018275:Carcinoma, Lobular / Q000453:epidemiology / Q000473:pathology*; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D006965:Hyperplasia; D015994:Incidence; D009361:Neoplasm Invasiveness; D016012:Poisson Distribution; D012307:Risk Factors; D018426:SEER Program; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology