Phase I/II Trial in ES-SCLC to Enhance Response to Atezolizumab Plus Chemotherapy With Total Body Irradiation

This phase I/II trial studies the side effects, safety, and effectiveness of low dose radiation to the entire body (total body irradiation \[TBI\]) and higher dose radiation to known areas of cancer (hypofractionated radiation therapy \[H-RT\]) combined with atezolizumab and chemotherapy (carboplatin \& etoposide) in treating patients with small cell lung cancer that has spread to disease sites outside of the lung (extensive stage). Extensive stage disease has historically been treated with chemotherapy alone with consideration of chest (thoracic) radiation therapy for those with response to chemotherapy, as well as consideration of preventative radiation therapy to the head (prophylactic cranial irradiation). Emerging evidence supports the synergistic interactions between immunotherapy and radiation therapy. Immunotherapy with monoclonal antibodies, such as atezolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Carboplatin is in a class of medications known as platinum-containing compounds. It works in a way similar to the anticancer drug cisplatin, but may be better tolerated than cisplatin. Carboplatin works by killing, stopping or slowing the growth of tumor cells. Etoposide is in a class of medications known as podophyllotoxin derivatives. It blocks a certain enzyme needed for cell division and DNA repair and may kill tumor cells. Combining TBI and H-RT with atezolizumab and chemotherapy may improve response to treatment.