title: Pathologic analysis of tumor size and lymph node status in multifocal/multicentric breast carcinoma.
abstract: BACKGROUND
  For unifocal invasive breast carcinoma, increasing tumor diameter predictably correlates with a greater frequency of lymph node involvement, thereby facilitating treatment decisions. In invasive breast tumors presenting with multiple nodules, however, it is unclear whether tumor size correlates with lymph node dissemination in a similar manner.
  
  
  METHODS
  The authors analyzed a series of 101 invasive breast carcinomas presenting with multiple macroscopically apparent lesions (2 foci: n = 77; 3: n = 20; 4: n = 4). Two different assessments of the tumor size (diameter of largest focus and combined diameter of all the foci) were then correlated with the status of axillary lymph nodes. For comparison with unifocal tumors, the authors used both external and internal control series (the latter consisting of 469 patients from their institution). The associations between lymph node status, tumor size, and multifocality were modeled using univariate and multivariate logistic regression, for each modality of tumor size assessment.
  
  
  RESULTS
  The logistic curves for multifocal and unifocal tumors were significantly different when the largest diameter was used as a tumor size estimate. Multifocal cases had higher frequencies of lymph node involvement than unifocal lesions of similar size category. In a multivariate logistic regression, the odds ratio of positive lymph node status in multifocal versus unifocal cases was 2.8 using largest diameter as a tumor size estimate (P < 0.0001). When the combined diameter assessment was used, however, the regression curve of multifocal cases was similar to that of unifocal cases, and the frequency of lymph node positivity was not significantly different in multifocal versus unifocal cases of the same size (odds ratio, 1.4; P = 0.13).
  
  
  CONCLUSIONS
  The authors' results show that, if aggregate diameters are used, unifocal and multifocal breast carcinomas are similar with respect to frequency of regional lymph node metastasis. Currently used algorithms, which use the diameter of the largest nodule, result in understaging of multifocal breast carcinomas due to underestimation of actual tumor size.
authors.affiliation: Department of Pathology, Harper Hospital, Wayne State University School of Medicine, Karmanos Cancer Institute, Detroit, Michigan 48201, USA. ah0047@wayne.edu
authors.forename: Aleodor A
authors.initials: AA
authors.lastname: Andea
authors.forename: Tracie
authors.initials: T
authors.lastname: Wallis
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Newman
authors.forename: David
authors.initials: D
authors.lastname: Bouwman
authors.forename: Jyotirmoy
authors.initials: J
authors.lastname: Dey
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Visscher
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology*; D002277:Carcinoma / Q000473:pathology*; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000473:pathology*; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D016609:Neoplasms, Second Primary / Q000473:pathology*; D011237:Predictive Value of Tests; D012044:Regression Analysis