title: Biologic characteristics of breast cancer detected by mammography and by palpation in a screening program: a pilot study.
abstract: OBJECTIVE
  To compare the histopathologic features and expression of p53 and c-erb B2 in the tumours detected by mammography only (clinically occult tumours) and the tumours detected by a nurse examiner (clinically palpable tumours).
  
  
  METHODS
  London branch of the Ontario Breast Screening Program, which uses both clinical breast examination and mammography as screening methods.
  
  
  METHODS
  Pathologic review and immunohistochemical staining of all tumours detected between 1990 and 1993.
  
  
  METHODS
  Categorization of tumours by detection method and analysis of tumour size, grade, type, lymph node status and c-erb B2 and p53 expression in each group.
  
  
  RESULTS
  From 1990 to 1993, 131 tumours were detected in patients ranging in age from 50 to 85 years (median 63 years). Sixty-seven occult tumours and 64 palpable lesions were detected. The occult tumours were significantly smaller (1.34 cm v. 2.29 cm, p < 0.0001) than the palpable ones and included a higher proportion of special-type lesions and ductal carcinoma in situ (43.3% v. 10.9%, p < 0.0001). Occult invasive carcinomas were of lower grade than palpable carcinomas (68.4% grade 1, 21.1% grade 2, 10.5% grade 3 v. 32.8% grade 1, 36.1% grade 2, 31.1% grade 3, p < 0.0001). Fewer occult lesions showed axillary nodal metastases (19.6% v. 40.6%, p = 0.02). No statistically significant differences were found for p53 or c-erb B2 positivity between the 2 groups.
  
  
  CONCLUSIONS
  Tumours detected by different screening methods in a screening program have different pathologic characteristics.
authors.affiliation: Department of Pathology, London Health Sciences Centre, Ont.
authors.forename: E
authors.initials: E
authors.lastname: Tweedie
authors.forename: K
authors.initials: K
authors.lastname: Tonkin
authors.forename: N
authors.initials: N
authors.lastname: Kerkvliet
authors.forename: G S
authors.initials: GS
authors.lastname: Doig
authors.forename: R K
authors.initials: RK
authors.lastname: Sparrow
authors.forename: F P
authors.initials: FP
authors.lastname: O'Malley
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000473:pathology; D002277:Carcinoma / Q000737:chemistry / Q000175:diagnosis / Q000473:pathology; D002278:Carcinoma in Situ / Q000737:chemistry / Q000175:diagnosis / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry / Q000175:diagnosis / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis; D008327:Mammography; D008875:Middle Aged; D010173:Palpation; D010865:Pilot Projects; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D016159:Tumor Suppressor Protein p53