Author of

• 15382

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  P3.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 235)

  • Event: WCLC 2015
  • Type: Poster
  • Track: Biology, Pathology, and Molecular Testing
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/09/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)

  • 15422

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    P3.04-040 - Comparison of Histology with Genome-Wide Copy Number Profiling in Patients with Metachronous or Synchronous Tumors (ID 3035)

    09:30 - 09:30  |  Author(s): B. Ylstra
    • Abstract

    Background:
    Multiple synchronous and metachronous lung tumors are frequently encountered in patients with lung cancer. In addition, tumors of head and neck (usually squamous cell carcinoma) have a chance for a second primary malignancy in the lung. For treatment purposes it is important to know whether tumors are related (clonal = metastases) or not (multiple primaries). Histopathological comparison of the synchronous or metachronous tumors has been associated with molecular analysis. The purpose of this study is to examine the value of histopathological scoring with genome-wide copy number profiling for determination of clonality.
    
    Methods:
    From cases in which array CGH for clonality analysis performed between 2006 and 2012 were selected if at least one intrathoracic tumor was present. In the first years genome-wide copy number profiling was performed with arrayCGH and later with shallow sequencing. Results of the genome-wide copy number profiling were compared to histological (sub)typing.
    
    Results:
    100 tumor pairs from 59 patients were examined. 32 pairs were discovered simultaneously (synchronous), the other 68 were metachronous. The histopathological diagnosis was similar in 74 cases (74%). genome-wide copy number profiling revealed evidence for clonality in 55% of the pairs, no-clonality in 28% and was undetermined in 17%. Comparing of histology with genome-wide copy number profiling revealed concordancy in 54 pairs ( 74%; 44 clonal en 10 non-clonal). In 18 of the 62 pairs where histology was similar the genome-wide copy number profiling revealed a non-clonal pattern. In 11 out of 21 pairs where histology differed between the pairs, genome-wide copy number profiling revealed a clonal pattern. Thus histology was not prognostic in 29/83 pairs (35%).
    
    Conclusion:
    For the determination of clonality in lung cancer histological examination is discordant with genome-wide copy number profiling in 35% of the comparisons. As histology is a poor predictor of clonality, genome-wide copy number profiling is preferred for clonality analysis between tumors.