<abstract xmlns="http://www.w3.org/1999/xhtml"><sec id="j_raon-2020-0046_s_006_w2aab3b7c42b1b6b1aab1c16b1Aa"><h3>Background</h3><p>Consolidation radiotherapy (cRT) in extended disease small cell lung cancer (ED-SCLC) showed improved 2-year overall survival in patients who responded to chemotherapy (ChT) in CREST trial, however results of two meta - analysis were contradictive. Recently, immunotherapy was introduced to the treatment of ED-SCLC, making the role of cRT even more unclear. The aim of our study was to access if consolidation thoracic irradiation improves survival of ED-SCLC patients treated in a routine clinical practice and to study the impact of cRT dose on survival. We also discuss the future role of cRT in the era of immunotherapy.</p></sec><sec id="j_raon-2020-0046_s_007_w2aab3b7c42b1b6b1aab1c16b2Aa"><h3>Patients and methods</h3><p>We retrospectively reviewed 704 consecutive medical records of patients with small cell lung cancer treated at the Institute of Oncology Ljubljana from January 2010 to December 2014 with median follow up of 65 months. We analyzed median overall survival (mOS) of patients with ED-SCLC treated with ChT only and those treated with ChT and cRT. We also compared mOS of patients treated with different consolidation doses and performed univariate and multivariate analysis of prognostic factors.</p></sec><sec id="j_raon-2020-0046_s_008_w2aab3b7c42b1b6b1aab1c16b3Aa"><h3>Results</h3><p>Out of 412 patients with ED-SCLC, ChT with cRT was delivered to 74 patients and ChT only to 113 patients. Patients with cRT had significantly longer mOS compared to patients with ChT only, 11.1 months (CI 10.1–12.0) <italic>vs</italic>. 7.6 months (CI 6.9–8.5, p &lt; 0.001) and longer 1-year OS (44% <italic>vs</italic>. 23%, p = 0.0025), while the difference in 2-year OS was not significantly different (10% <italic>vs</italic>. 5%, p = 0.19). The cRT dose was not uniform. Higher dose with 45 Gy (in 18 fractions) resulted in better mOS compared to lower doses 30–36 Gy (in 10–12 fractions), 17.2 months <italic>vs</italic>. 10.3 months (p = 0.03) and statistically significant difference was also seen for 1-year OS (68% <italic>vs</italic>. 30%, p = 0.01) but non significant for 2-year OS (18% <italic>vs</italic>. 5%, p = 0.11).</p></sec><sec id="j_raon-2020-0046_s_009_w2aab3b7c42b1b6b1aab1c16b4Aa"><h3>Conclusions</h3><p>Consolidation RT improved mOS and 1-year OS in ED-SCLC as compared to ChT alone. Higher dose of cRT resulted in better mOS and 1-year OS compared to lower dose. Consolidation RT, higher number of ChT cycles and prophylactic cranial irradiation (PCI) were independent prognostic factors for better survival in our analysis. For patients who received cRT, only higher doses and PCI had impact on survival regardless of number of ChT cycles received. Role of cRT in the era of immunotherapy is unknown and should be exploited in further trials.</p></sec></abstract>

BackgroundConsolidation radiotherapy (cRT) in extended disease small cell lung cancer (ED-SCLC) showed improved 2-year overall survival in patients who responded to chemotherapy (ChT) in CREST trial, however results of two meta - analysis were contradictive. Recently, immunotherapy was introduced to the treatment of ED-SCLC, making the role of cRT even more unclear. The aim of our study was to access if consolidation thoracic irradiation improves survival of ED-SCLC patients treated in a routine clinical practice and to study the impact of cRT dose on survival. We also discuss the future role of cRT in the era of immunotherapy.Patients and methodsWe retrospectively reviewed 704 consecutive medical records of patients with small cell lung cancer treated at the Institute of Oncology Ljubljana from January 2010 to December 2014 with median follow up of 65 months. We analyzed median overall survival (mOS) of patients with ED-SCLC treated with ChT only and those treated with ChT and cRT. We also compared mOS of patients treated with different consolidation doses and performed univariate and multivariate analysis of prognostic factors.ResultsOut of 412 patients with ED-SCLC, ChT with cRT was delivered to 74 patients and ChT only to 113 patients. Patients with cRT had significantly longer mOS compared to patients with ChT only, 11.1 months (CI 10.1–12.0) vs. 7.6 months (CI 6.9–8.5, p < 0.001) and longer 1-year OS (44% vs. 23%, p = 0.0025), while the difference in 2-year OS was not significantly different (10% vs. 5%, p = 0.19). The cRT dose was not uniform. Higher dose with 45 Gy (in 18 fractions) resulted in better mOS compared to lower doses 30–36 Gy (in 10–12 fractions), 17.2 months vs. 10.3 months (p = 0.03) and statistically significant difference was also seen for 1-year OS (68% vs. 30%, p = 0.01) but non significant for 2-year OS (18% vs. 5%, p = 0.11).ConclusionsConsolidation RT improved mOS and 1-year OS in ED-SCLC as compared to ChT alone. Higher dose of cRT resulted in better mOS and 1-year OS compared to lower dose. Consolidation RT, higher number of ChT cycles and prophylactic cranial irradiation (PCI) were independent prognostic factors for better survival in our analysis. For patients who received cRT, only higher doses and PCI had impact on survival regardless of number of ChT cycles received. Role of cRT in the era of immunotherapy is unknown and should be exploited in further trials.

Consolidation radiotherapy for patients with extended disease small cell lung cancer in a single tertiary institution: impact of dose and perspectives in the era of immunotherapy

Radiology and Oncology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

BackgroundConsolidation radiotherapy (cRT) in extended disease small cell lung cancer (ED-SCLC) showed improved 2-year overall survival in patients who...

Consolidation radiotherapy for patients with extended disease small cell lung cancer in a single tertiary institution: impact of dose and perspectives in the era of immunotherapy

Article Category: Research Article

Published Online: Jul 29, 2020

Page range: 353 - 363

Received: Mar 09, 2020

Accepted: Jul 04, 2020

DOI: https://doi.org/10.2478/raon-2020-0046

© 2020 Karmen Stanic, Martina Vrankar, Jasna But-Hadzic, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.