title: Lobular Carcinoma in Situ: A 29-Year Longitudinal Experience Evaluating Clinicopathologic Features and Breast Cancer Risk.
abstract: OBJECTIVE
  The increased breast cancer risk conferred by a diagnosis of lobular carcinoma in situ (LCIS) is poorly understood. Here, we review our 29-year longitudinal experience with LCIS to evaluate factors associated with breast cancer risk.
  
  
  METHODS
  Patients participating in surveillance after an LCIS diagnosis are observed in a prospectively maintained database. Comparisons were made among women choosing surveillance, with or without chemoprevention, and those undergoing bilateral prophylactic mastectomies between 1980 and 2009.
  
  
  RESULTS
  One thousand sixty patients with LCIS without concurrent breast cancer were identified. Median age at LCIS diagnosis was 50 years (range, 27 to 83 years). Fifty-six patients (5%) underwent bilateral prophylactic mastectomy; 1,004 chose surveillance with (n = 173) or without (n = 831) chemoprevention. At a median follow-up of 81 months (range, 6 to 368 months), 150 patients developed 168 breast cancers (63% ipsilateral, 25% contralateral, 12% bilateral), with no dominant histology (ductal carcinoma in situ, 35%; infiltrating ductal carcinoma, 29%; infiltrating lobular carcinoma, 27%; other, 9%). Breast cancer incidence was significantly reduced in women taking chemoprevention (10-year cumulative risk: 7% with chemoprevention; 21% with no chemoprevention; P < .001). In multivariable analysis, chemoprevention was the only clinical factor associated with breast cancer risk (hazard ratio, 0.27; 95% CI, 0.15 to 0.50). In a subgroup nested case-control analysis, volume of disease, which was defined as the ratio of slides with LCIS to total number of slides reviewed, was also associated with breast cancer development (P = .008).
  
  
  CONCLUSIONS
  We observed a 2% annual incidence of breast cancer among women with LCIS. Common clinical factors used for risk prediction, including age and family history, were not associated with breast cancer risk. The lower breast cancer incidence in women opting for chemoprevention highlights the potential for risk reduction in this population.
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY. tking7@partners.org.
authors.forename: Tari A
authors.initials: TA
authors.lastname: King
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Melissa
authors.initials: M
authors.lastname: Pilewskie
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Shirin
authors.initials: S
authors.lastname: Muhsen
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Sujata
authors.initials: S
authors.lastname: Patil
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Starr K
authors.initials: SK
authors.lastname: Mautner
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Anna
authors.initials: A
authors.lastname: Park
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Sabine
authors.initials: S
authors.lastname: Oskar
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Elena
authors.initials: E
authors.lastname: Guerini-Rocco
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Camilla
authors.initials: C
authors.lastname: Boafo
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Jessica C
authors.initials: JC
authors.lastname: Gooch
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Marina
authors.initials: M
authors.lastname: De Brot
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Jorge S
authors.initials: JS
authors.lastname: Reis-Filho
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Mary
authors.initials: M
authors.lastname: Morrogh
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Victor P
authors.initials: VP
authors.lastname: Andrade
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Rita A
authors.initials: RA
authors.lastname: Sakr
authors.affiliation: All authors: Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Monica
authors.initials: M
authors.lastname: Morrow
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D002173:Cancer Care Facilities; D002278:Carcinoma in Situ / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D018275:Carcinoma, Lobular / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D016022:Case-Control Studies; D016208:Databases, Factual; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D015412:Mastectomy, Segmental / Q000379:methods; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness / Q000473:pathology; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D009367:Neoplasm Staging; D009519:New York City; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D055502:Secondary Prevention / Q000379:methods; D016019:Survival Analysis; D013629:Tamoxifen / Q000627:therapeutic use; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D013629:Tamoxifen