Author of

• 11866

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  P2.18 - Poster Session 2 - Pathology (ID 176)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Pathology
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/29/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 11884

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    P2.18-018 - Outcomes of lung adenocarcinoma patients with signet ring cell tumors: a three-way evaluation (ID 2884)

    09:30 - 09:30  |  Author(s): A. Jatoi
    • Abstract

    Background
    Pathologically, signet ring cells (SRC) describe singly dispersed tumor cells with intracytoplasmic mucin vacuoles, which eccentrically displace and compress the nucleus. SRCs are traditionally associated with adenocarcinoma of the gastrointestinal tract and are rare in lung adenocarcinoma (LACA). Patients with primary LACA with SRC features (SRC+) have been associated with poor clinical outcome and ALK gene rearrangement (ALK+). However, the impact of SRC+ on clinical outcome is not well delineated. We systematically studied LACA survival outcomes for the impact of SRC status.

    Methods
    Three distinct groups of surgically treated patients with LACA (n=763) that were followed for ≥5 years were reviewed: never smokers (n=266), 2006-2007 cohort (n=222), and smokers enriched for various degrees of lepidic growth pattern (LGP, n=275). Two pulmonary pathologists reviewed all cases; SRC+ tumors were defined as having >10% SRCs, agreed by both pathologists. SRC+ tumors were TTF1+, and generally cytoplasmic mucin+ and CDX2-. ALK immunostain was performed on all SRC+ cases, and ALK status was confirmed by FISH for cases with any degree of immunoreactivity. Impact of SRC+ on patients’ survival outcomes (overall and disease-free, OS and DFS) were analyzed using Cox models (by hazard ratio, HR) separately for the three groups, with careful evaluation of known prognostic factors: age at diagnosis; gender; smoking status; lung cancer history; tumor subtype; grade and stage; and treatment (surgery, chemotherapy and/or radiation).

    Results
    In the total of 763 patients (61% women, mean age at diagnosis 68 years), 53 (7%) were SRC+. In never smokers (73% women), 9% were SRC+; 33% of the SRC+ were ALK+ vs. 5% among the SRC- cases (p<0.0001). In the 2006-2007 cohort (55% women), 9% were SRC+; in LGP-smokers (54% women), 3% were SRC+. Across all three groups, SRC+ tumors were more likely to occur in men and have higher stage. Univariate analysis showed SRC+ never smokers had shorter survival: median DFS was 2.4 years (vs. 5.2 in SRC- never smokers, p=0.0004), and median OS was 3.7 years (vs. 7.6, p=0.0064). However, multivariate analysis did not confirm a significant impact of SRC+ on survival. In contrast, for the other two groups, crude 5-year survival was 6%-27% decreased in SRC+ cases compared to SRC- cases (none reached statistical significance); however, multivariate analysis revealed a 2-fold higher mortality (HR=2.30, 95% CI=1.01-5.27, p=0.048) for smokers with SRC+ tumors.

    Conclusion
    Based on results from three patient groups, we confirmed that SRC+ is significantly associated with ALK+. Worse survival in patients with SRC+ tumors was observed in never smokers by univariate analysis. A potential negative impact of SRC+ tumors on OS in LGP-smokers was only uncovered after adjusting for known prognostic factors. These results need to be furthered confirmed.