ESTRO 2023 - Abstract Book

S1170

Digital Posters

ESTRO 2023

years and for RS 65.3 years. The histology in NRS and RS were respectively; Myxofibrosarcoma n=2, n=2), spindle cell (n=0, n =3), undifferentiated pleomorphic sarcoma (n=1, n=2), leiomyosarcoma (n=2, n=1), myxoid liposarcoma (n=2, n=1), and other (n=2, n=0). For RS the mean NLR at diagnosis was 4.14 (95%CI= 3.12-5.15), at post-RT 3.72 (95%CI=2.52-4.92), at recurrence 8.43 (95%CI= 3.86-13.01) and at the time of second-RT 5.39 (95%CI= 2.91-7.88). For NRS the mean NLR at diagnosis was 2.55 (95%CI= 0.31-1.48) and post-RT 4.29 (95%CI= (0.66-3.15). The delta changes in NLR (dNLR) between diagnosis and RT for RS was 0.99 (95%CI= 0.11-1.83) and for NRS was 1.73 (95%CI= 1.14-8.66). The baseline diagnostic NLR in RS and NRS was not correlated with histology or age. The baseline diagnostic NLR among both RS and NRS showed a significant correlation between tumor and higher NLR (t-test, p= 0.0108). In the RS group, 2 patients died of disease. These patients had the highest dNLR between post-RT and recurrence above 3.7. Conclusion A higher baseline NLR at diagnosis is associated with worse local control in STS and with larger tumor at diagnosis. Dynamic changes in NLR for RS can predict better outcomes and detect the time of recurrence. A high dNLR between diagnosis and RT is associated with better outcomes. Despite the small number of patients, this is the first study to assess the dynamic changes in NLR and its association with prognosis and prediction of recurrence in STS.

PO-1445 Pituitary transforming tumor gene (PTTG). A new biomarker for lung adenocarcinoma?

P. Romero Pareja 1 , E. Gomis Selles 1 , O. Muñoz Muñoz 1 , I. Paguey Garrido 1 , B.D. Delgado Leon 1 , J.L. Lopez Guerra 1

1 Virgen del Rocio University Hospital, Radiation Oncology, Seville, Spain

Purpose or Objective The pituitary tumor transforming gene (PTTG) encodes a protein called securin. Overexpression of mRNA has been associated with higher mortality at 5 years in patients diagnosed with non-small cell lung cancer (NSCLC). Our team studies the validation of this association by analyzing securin protein expression levels and survival in NSCLC patients. Materials and Methods We reviewed diffferent bibliographies about several gene biomarkers and the prognostic role of mRNA overexpression in NSCLC, both in vitro and clinically. Subsequently, we recruited a cohort of 285 patients from our center diagnosed with NSCLC for whom tumor tissue samples were available. PTTG levels were examined by immunohistochemistry. Two independent pathologists, blinded to clinical data, categorized PTTG expression. Results Our cohort was characterized by a median age of 68 years and a male gender distribution (77.2%). The stage of the disease at diagnosis, stage III stood out (61%), followed by stages I (24%), IV (8%) and II (7%). Most of the patients underwent surgery (90%), while throughout the process 86% received radiotherapy. PTTG mRNA overexpression was associated with lower overall survival (OS), without statistical significance (p=0.151). When analyzing the cohort by histological subgroups, lower OS was observed in patients diagnosed with NSCLC with adenocarcinoma histology (N=145) and high expression of PTTG (p=0.032) (Figure 1).

Conclusion In our cohort, PTTG overexpression is associated with a higher risk of mortality in NSCLC, with statistical significance in those cases with adenocarcinoma histology. This response biomarker may be useful to predict prognosis and as a therapeutic target in NSCLC.

PO-1446 Systematic Review of Prognostic and Predictive Biomarkers in HNSCC Treated with Radiotherapy

D. Schanne 1 , A. Koch 1 , O. Elicin 1 , R. Giger 2 , M. Medová 3 , Y. Zimmer 3 , D.M. Aebersold 1