Benefits of postoperative thoracic radiotherapy for small cell lung cancer subdivided by lymph node stage: a systematic review and meta-analysis

The most common cause of cancer-related deaths worldwide is lung cancer, among which small cell lung cancer (SCLC) accounts for approximately 15% (1). SCLC is extremely malignant and characterized by a rapidly progressing primary mass, early lymph node metastases and distant disseminations (2). As recommended in the European Society for Medical Oncology (ESMO) (3) and National Comprehensive Cancer Network (NCCN) (4) guidelines, the combination of chemotherapy and thoracic radiotherapy is the current standard of care for limited-stage SCLC, and subsequent prophylactic cranial irradiation (PCI) is given when patients show significant response to chemoradiotherapy. The progress made in early diagnosis and surgical techniques for lung cancer in recent years has resulted in surgery having a more important role in limited early stage SCLC. Some retrospective analyses have shown that surgical-based multi-modality treatment significantly improved the 5-year survival compared with chemoradiotherapy alone for patients with early SCLC (5-9) (summarized in Table 1). Thus, in fit patients, especially those with peripherally located and early T stage SCLC, and negative mediastinal lymph nodes on CT scan, PET-CT scan or EBUS and/or mediastinoscopy, surgery may be a valid alternative to chemoradiotherapy (3,4). However, the local-regional recurrence (LRR) rate still ranged from 10–20% after surgery (10,11), underscoring the need to define better postoperative therapeutic strategies