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E. Sottotetti



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    Poster Display Session (ID 63)

    • Event: ELCC 2017
    • Type: Poster Display Session
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 5/07/2017, 12:30 - 13:00, Hall 1
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      56P - Pro-GRP in small cell lung cancer (ID 288)

      12:30 - 13:00  |  Author(s): E. Sottotetti

      • Abstract

      Background:
      NSE was historically the recommended tumor marker for SCLC. It stains up to 80% of SCLCs in tissue examinations but is also elevated in the sera of 20–30% of patients with NSCLC. NSE has low sensitivity, particularly in patients with limited disease (LD). Recently, pro-gastrin-releasing peptide (pro-GRP) became available as a sensitive, specific and reliable tumor marker for patients with SCLC.

      Methods:
      We retrospectively analyzed pro-GRP in pts with SCLC and NSCLC treated from 2015 to 2016 at our Center. Serum pro-GRP level was measured with electrochemiluminescence method at our laboratory; it was considered elevated if higher than 77.8 pg/ml. Statistical tests used to study differences between pro-GRP medians were Mann-Whitney U test for SCLC vs NSCLC and Fisher’s exact test for DD vs LD. To calculate sensitivity (Sn), specificity (Sp), positive and negative predictive values (PPV and NPV respectively) we considered: SCLC with elevated pro-GRP as true positive (TP), NSCLC with normal pro-GRP as true negative (TN), SCLC with normal pro-GRP as false negative (FN), NSCLC with elevated pro-GRP as false positive (FP).

      Results:
      A total of 46 pts were studied (33 men, 13 women), whose median age was 67 years (range 20-78). 20 pts had SCLC (16 DD, 4 LD) and 26 metastatic or unresectable advanced NSCLC. Median pro-GRP level was 1398 pg/ml (range 43-50000) in SCLC and 26 pg/ml (range 6-119.2) in NSCLC (difference 1372 pg/ml; SCLC/NSCLC ratio 53.76; p < 0.01). TPs were 18, FNs 2, TNs 25, FP 1. Sn was 90%, Sp 96.15%, PPV 94.73% and NPV 92.59%. All the TPs had diffuse disease, the 2 FNs had limited disease, the only FP had a poorly differentiated adenocarcinoma. Median pro-GRP was 182.25 pg/ml (range 43-642) in LD pts and 2522 pg/ml (range 88-50000) in those with DD (absolute difference 2339.75 pg/ml; ratio DD/LD 13.83; p = 0.026). Pro-GRP was elevated in all DD pts and in half of LD pts (2/4): Both of them had a high burden of loco-regional disease.

      Conclusions:
      Our data confirm that pro-GRP is sensitive for SCLC diagnosis and that it might help to discriminate DD from LD. Since high marker levels are related to a high disease burden, pro-GRP may have a negative prognostic significance. Follow up is required to define its role in clinical practice in monitoring response to treatment.

      Clinical trial identification:
      Not applicable

      Legal entity responsible for the study:
      Fondazione IRCCS Istituto Nazionale dei Tumori

      Funding:
      Fondazione IRCCS Istituto Nazionale dei Tumori

      Disclosure:
      All authors have declared no conflicts of interest.