Interobserver variability in breast carcinoma grading results in prognostic stage differences

Kimmie Rabe, Olivia L. Snir, Veerle Bossuyt, Malini Harigopal, Romulo Celli, Emily S. Reisenbichler

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


The AJCC Cancer Staging Manual 8th edition included tumor grade in the pathologic prognostic stage for breast carcinomas. Due to the known subjectivity of tumor grading, we aimed to assess the degree of interobserver agreement for invasive carcinoma grade among pathologists and determine its effect on pathologic prognostic stage. One hundred consecutive cases of invasive stage II carcinomas were independently graded twice, with an 4-week intervening wash-out period, by 6 breast pathologists utilizing established Nottingham grading criteria. Inter- and intra-observer variability was determined for overall grade and for each of the 3 scoring components. Interobserver variability was good to very good (κ range = 0.582–0.850) with even better intra-observer variability (mean κ = 0.766). Tubule score was the most reproducible element (κ = 0.588). Complete concordance was reached in 54 cases and 58 cases in rounds 1 and 2 respectively. In round 1 this resulted in different pathologic prognostic stage in only 25 of discordant cases, 18 of which were stage IA versus IB. In conclusion, grading agreement between pathologists was good to very good and discordant grades resulted in small changes to pathologic prognostic stage.

Original languageEnglish (US)
Pages (from-to)51-57
Number of pages7
JournalHuman pathology
StatePublished - Dec 2019


  • AJCC
  • Breast carcinoma
  • Histologic grade
  • Interobserver variability
  • Prognostic stage

PubMed: MeSH publication types

  • Journal Article


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