Author of

• 10923

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  P1.18 - Poster Session 1 - Pathology (ID 175)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Pathology
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/28/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 10939

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    P1.18-016 - The association between size and histology in discarded intrapulmonary lymph nodes (LN) from non-small cell lung cancer (NSCLC) resection specimens: can we select nodes for examination by their size? (ID 2996)

    09:30 - 09:30  |  Author(s): X. Yu
    • Abstract

    Background
    Pathologic nodal staging is the most important prognostic factor in resected NSCLC, but LN yields are low. A median of 3 N1 nodes are examined in US lung resection specimens, though fastidious examination yields a median of 11 N1 LN. A bias towards examination of larger nodes may cause understaging when small LN with metastasis are missed. We examined the size and histologic characteristics of LN material retrieved during a fastidious redissection of discarded lung cancer resection specimens.

    Methods
    Prospective study of lobectomy specimens discarded after completion of the routine pathology examination. A fastidious redissection protocol was used to retrieve all grossly LN-like material for histologic examination, irrespective of size. The Wilcoxon-Mann-Whitney test was used to compare the materials with and without metastasis.

    Results
    1094 LN-like materials retrieved from 112 resection specimens: 345 (32%) were not LN on histologic examination (including 11 satellite metastatic nodules); 749 (68%) were LN, of which 71 (9%) had metastasis. The distribution of size and histology is shown (Figure). The median size (range) of the non-LN, LN without metastasis, and LN with metastasis was: 4.0 (0.9 - 20); 6.0 (1.0 - 27), 12.0 (1.0 - 27) mm (p<.0001, for all comparisons). Twenty-six patients (23%) had LN with metastasis (see histogram). In 4 patients, LN with metastasis were smaller than LN without metastasis.Figure 1Figure 2

    Conclusion
    Despite the statistically significant tendency for LN with metastasis to be larger than those without metastasis, there was broad size distribution overlap. Furthermore, a third of materials that grossly appeared to be LN were not, though some were satellite metastatic nodules. This probably contributes to the relatively low LN yield in routine examinations. LN size is not a reliable means of distinguishing between those with and without metastasis. The protocol for gross N1 LN retrieval should be modified to facilitate a more thorough routine examination.