ESTRO 2023 - Abstract Book

S1054

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ESTRO 2023

were stage IV and only 3.1 % stage I. Sixty seven percent of the patients diagnosed at stage III and IV were in 56-75 years old and 92% of them were male. According to the tumor stage 27% and 35% were T3 and T4 respectively and about 47% were N2 stage at the diagnosis and 8% were N3. According to the region distribution of the NSCLC the data showed a homogeneous distribution with a higher peak in the central region with 30.6%, Tirana and coastal region with 26 % each and 17.4% in the mountain region. In the multivariate analysis significant correlation was found in gender with histopathological type (p<0.0001), disease stage at diagnosis (p=0.04) and smoking (p<0.0001). Conclusion Our data represent the first evaluation of NSCLC in Albania. High percentage on advanced and metastatic stage at diagnosis confirms that early diagnosis of NSCLC remains a challenge in our country. Implementation of screening program and sensibilisation on the smoking risk remain crucial. M. Gonzalez De Dueñas 1 , J. Cabrera Rodriguez 2 , C. Corral Fernandez 3 , V. Vera Barragán 3 , E. Agudo Rey 3 , M. Medina Cobacho 3 , Y. Rios Kavadoy 4 , J. Quirós Rivero 3 , M.F. Ropero Carmona 5 , J. Muñoz Garcia 3 , T.P. Iglesias Garcia 3 , F. Garcia Urra 3 1 Hospital Universitario de Badajoz, Radiotherapy Oncology, Badajoz, Spain; 2 Hospital Universitario de Badajoz, radiotherapy oncology, Badajoz, Spain; 3 Hospital Universitario de Badajoz, radiotherapy oncology, Badajoz, Spain; 4 Hospital Universitario de Badajoz, radiotherapy oncology, Badajoz,, Spain; 5 Hospital Universitario de Badajoz,, radiotherapy oncology, Badajoz, Spain Purpose or Objective To assess the prognostic value of the association between post-CRT [18F]FDG PET/CT metabolic response and pathologic response in patients treated with neoadjuvant CRT (neoCRT) plus surgery for NSCLC. Materials and Methods Retrospective study of patients treated with neoCRT according to institutional protocol as per Multidisciplinary Tumor Board (MTB) consensus. All patients underwent a pre-treatment [18F]FDG PET/CT. After completing neoCRT they had a second post-treatment PET/CT scheduled at week +4. Patients had surgery between at week +6 to +8 if MTB deemed the case resectable after evaluation of tumor response . Results 60 patients received neoCRT consisting of platinum-based doublet plus concomitant thoracic radiotherapy (60 Gy) of whom 43 ultimately underwent surgery and were included for analysis. The median follow-up was 5.5 years. The median OS has not been reached, mean OS was 10.1 years. Metabolic complete response (mCR) was obtained in 13 (30.2%) pathological CR (pCR) in 16 (37.2%) of whom 6 had metabolic partial response (mRP). 7 patients (16.3%) achieved both mCR and pCR. The sensitivity and specificity of [18F]FDG PET/CT for predicting pathologic response was 77.8% and 56.2% respectively. PPV and NPV was 70% and 53.8% respectively. 5-year OS for patients who achieved both mCR plus pCR was 100%, p = 0.04, compared with those who had persistent disease of any type: mPR plus pCR: 62%, mCR plus pPR: 50 %, mPR plus pPR: 44%. OS differences between the last 3 groups were not significant. Conclusion Patients with NSCLC treated with neoCRT plus surgery who achieve both mCR and pCR have an excellent prognosis. Although both the sensitivity and specificity of [18F]FDG PET/CT have shown a poor performance diagnosing histological response, the prognostic value of PET/CT seems to be important since a positive post-treatment result (e.g. mPR) influences OS even in patients without pathological residual tumor (pCR). 1 Leeds Cancer Centre, Leeds Teaching Hospital Trust, Oncology, Leeds, United Kingdom; 2 Leeds institute of Medical Research at St James's, University of Leeds, Oncology, Leeds, United Kingdom Purpose or Objective Re-irradiation (reRT) is increasingly attempted for patients with lung cancer recurrence or a new second lung primary after past thoracic radiotherapy. Data on outcomes for this patient group remain sparse, however. We aimed to evaluate cancer outcomes and toxicities for a large retrospective cohort of patients receiving curative dose reRT for recurrent lung malignancy at a tertiary cancer centre. Materials and Methods Patients were identified by automatic search of radiotherapy electronic patient records, with additional manual review for eligibility. All patients received at least two courses of radiotherapy to the thorax between 2010 – 2020 for lung malignancy (either recurrence or new primary), with ≥ 6 months between treatments, with potential overlap between treatment fields (targets on same level or within 2cm cranio-caudal), and radiotherapy dose >30 Gy for both treatments. Treatment and demographic data were extracted automatically; outcome data collected manually from patient records. First site of disease progression after reRT was classified as ‘site of re-treatment’, ‘elsewhere in lung’, or ‘distant metastasis’. Death was split into cancer and non-cancer deaths. Overall survival (OS) and cancer-specific survival were calculated using Kaplan Meier estimators, with all times calculated from end of reRT. A competing risk framework was used to estimate the PO-1315 Association between metabolic and pathologic response after neoadjuvant CRT for NSCLC PO-1316 Re-irradiation of the thorax for lung malignancy: A cohort study of cancer outcomes and toxicity D. Lowe 1 , J. Baldwin 1 , M. Teo 1 , A. Appelt 2,1