Placebo-controlled, Study of Concurrent Chemoradiation Therapy With Pembrolizumab Followed by Pembrolizumab and Olaparib in Newly Diagnosed Treatment-Naïve Limited-Stage Small Cell Lung Cancer (LS-SCLC) (MK 7339-013/KEYLYNK-013) ~52 mi. (Vilnius, Lithuania, +122 more cities) Nacionalinis Vezio Institutas ( Site 2300) Small Cell Lung Carcinoma etoposide, +5 more drugs chemotherapy, +3 more types