Abscopal effect of radiation therapy and nivolumab in a patient with combined small-cell lung cancer: a case report.

The paradigm for combined small-cell lung carcinoma (C-SCLC) is according to standard SCLC treatment with poor outcomes. The efficacy of immune checkpoint inhibitor (ICI) monotherapy for pretreated SCLC is still limited. Clinical researches exploring radiotherapy combined with immunotherapy showed promising synergistic effects in several tumors. We report one C-SCLC case after resistant to comprehensive treatment receiving nivolumab combined with radiotherapy achieving clinical complete remission (CCR). The combination module of ICI and radiation could be an option for relapsed C-SCLC, and the prognostic indicators need further research. Combined small-cell lung carcinoma (C-SCLC) is a rare type of lung cancer that shows more than two types of mixed pathology within the same tumor with poor outcomes. The treatment regimen is a combination of surgery, chemotherapy, radiotherapy and immunotherapy. Clinical research exploring radiotherapy combined with immunotherapy showed promising synergistic effects in several tumors excluding C-SCLC. In the present case, we used immunotherapy and radiotherapy as salvage treatments for a pretreated C-SCLC patient and achieved clinical complete remission. We analyzed some biomarkers of the patient, to explain the mechanisms of efficacy for immunotherapy combined with radiotherapy. The module of immunotherapy combined with radiotherapy may provide a new option for the treatment of C-SCLC.