Patterns of Failure and the Prognostic Factors of the Patients with LD SCLC according to the TNM Staging; TOG-TROD Study

The prognostic factors and patterns of relapse were retrospectively analyzed according to the TNM staging in Turkish patients with limited SCLC on behalf of Turkish Oncology Group(TOG)-Turkish Radiation Oncology Association(TROD). The data of 266 patients with limited disease SCLC from 13 multiple oncology centers who have at least 1 year follow-up were analyzed. The patients were restaged according to TNM staging by means of their initial thorax-CT or PET-CT. Brain MRI was performed for all of the patients before treatment. Median age was 59(21-86) years old and 85% of the patients were male. PET-CT was used in 62.4% of the patients for staging. Concomitant chemoradiotherapy with Cisplatinum-Etoposide was given in 38.3% of the patients. Median thoracic radiotherapy dose was 56Gy (30-66.8Gy). PCI was performed to the 180 patients (67.7%), The effect of age, gender, clinical stage, T, N stage and prophylactic cranial irradiation (PCI) on OS and DFS rates were analyzed in both univariate and multivariate analysis with Log-rank and cox regression tests. Median follow-up was 19 months (6-113) for the patients who are alive. Thirty-six percent of the patients had LR and approximately half of the patients developed DM. The most common metastases were seen in brain, liver and bone respectively. 2 and 5 years OS and DFS were 45.3%-20.6% and 32.2%-17.1% retrospectively. On univariate analysis, OS was significantly better in the patients with T1, N0-1 tumors and clinical stage I-II than the others and patients who did not developed brain and DM and thoracic radiotherapy dose ≥60Gy(p<0.05). DFS was superior in patients with N0-1 tumor, stage I-II disease, who received PCI and thoracic radiotherapy dose ≥60Gy (p<0.05). On multivariate analysis, PCI was found to be an independent factor affecting DFS (p=0.042). DM, thoracic radiotherapy dose were significant prognostic factors for OS (p=0.048, <0.0001 respectively). 64 patients developed brain metastases with a median 16 months (6-113months). Brain metastases were find to be significantly less in the patients with N0, stage I-II disease and who were treated by PCI. Limited disease definition includes wide spectrum of patients, therefore TNM staging should be useful in order to predict the prognosis of the patients. In our series, DFS and OS was superior for the patients with T1 and N0-NI tumors than the others. Besides, the patients with T1 and N0 tumors developed fewer brain metastases, therefore PCI might be omitted for some of the patients with early staged tumor.