Thoracic radiotherapy in small cell lung cancer—a narrative review

Abstract

Small-cell lung cancer (SCLC) represents 10-15% of all lung cancers and has a poor prognosis.Thoracic radiotherapy plays a central role in current SCLC management. Concurrent chemoradiotherapy (CTRT) is the standard of care for localised disease (stage I−III, limited-stage, LS). Definitive thoracic radiotherapy may be offered in metastatic patients (stage IV, extensive stage, ES-SCLC) after chemotherapy.For LS-SCLC, the gold standard is early accelerated hyperfractionated twice-daily CTRT (4 cycles of cisplatin etoposide, starting with the first or second chemotherapy cycle). Modern radiation techniques should be used with involved-field radiotherapy based on baseline CT and PET/CT scans. In ES-SCLC, thoracic radiotherapy should be discussed in cases of initial bulky mediastinal disease/residual thoracic disease not progressing after induction chemotherapy. This strategy was however not assessed in recent trials establishing chemo-immunotherapy as the standard first line treatment in ES-SCLC. Future developments include technical radiotherapy advances and the incorporation of new drugs. Thoracic irradiation is delivered more precisely given technical developments (IMRT, image-guided radiotherapy, stereotactic radiotherapy), reducing the risks of severe adverse events. Stereotactic ablative radiotherapy may be discussed in rare early stage (T1 to 2, N0) inoperable patients. A number of current clinical trials are investigating immunoradiotherapy. In this review, we highlight the current role of thoracic radiotherapy and describe ongoing research in the integration of biological surrogate markers, advanced radiotherapy technologies and novel drugs in SCLC patients.

Using inflammatory indexes and clinical parameters to predict radiation esophagitis in patients with small-cell lung cancer undergoing chemoradiotherapy

“…Chemoradiotherapy is the primary treatment regimen in patients with small cell lung cancer (SCLC), especially limited-stage small cell lung cancer (LS-SCLC) ( 13 ). In extensive-stage small cell lung cancer (ES-SCLC), if patients had a complete or partial response to the initial systemic treatment, thoracic radiotherapy can be performed ( 14 ).…”

Successful IMRT and concurrent chemotherapy for a patient with intrathoracic extensive‐stage small cell lung cancer

“…For the first‐line treatment of ES‐SCLC, chemoimmunotherapy of platinum and etoposide combined with anti‐PD‐L1 antibodies including atezolizumab and durvalumab has been shown to improve survival and has become the standard of care. 1 , 5 , 6 , 7 In this treatment setting, the role of consolidative TRT is less clear. In this regard, a phase II/III RAPTOR trial (NRG Oncology LU‐007) is very important which compares the effect of adding RT (up to five sites including primary thoracic disease) to the usual maintenance therapy with atezolizumab versus atezolizumab alone in ES‐SCLC patients without progressive disease after four to six cycles of platinum plus etoposide chemotherapy combined with atezolizumab.…”

“…For the first‐line treatment of ES‐SCLC, chemoimmunotherapy of platinum and etoposide combined with anti‐PD‐L1 antibodies including atezolizumab and durvalumab has been shown to improve survival and has become the standard of care 1,5‐7 . In this treatment setting, the role of consolidative TRT is less clear.…”

“…5,6 Intensity-modulated RT (IMRT) is an innovative radiation technique that optimizes the dose distribution in three dimensions (3D) by focusing radiation on tumour burdens from multiple directions with nonuniform dose intensity in the radiation field, thereby reducing the dose to normal tissues around the tumour and surrounding organs. 7 It has a very wide range of applications, including large tumours or targets that are difficult to treat with ordinary 3D-RT. NRG/ RTOG 0617 trial showed that patients treated with IMRT had significantly less G3-5 pneumonitis and lower heart doses in locally advanced non-SCLC.…”

Radiation induced therapeutic effects in cancerous and tumor cells: A review

“…61 Thoracic radiation therapy has become more precise and has reduced risk of serious adverse events due to technical developments (IMRT, image-guided radiation therapy, stereotactic body radiation therapy. 62 Small cell lung cancer. 63 Interleukins at baseline 1b and neutrophil counts, and cytokeratin 19 antigens with initial treatment predicted response to radiotherapy in lung cancer.…”