[Successful Treatment of Squamous Cell Lung Cancer without PD-L1 Expression Using Fourth-Line Nivolumab].

A 71-year-old woman was diagnosed with stage ⅢB locally advanced lung squamous cell cancer(cT0N3M0).Programmed death-ligand 1(PD-L1)immunostaining was negative.First -line nedaplatin plus docetaxel and second-line carboplatin plus nab-paclitaxel were followed by sequential thoracic radiation therapy(60 Gy).The patient developed radiation pneumonitis, but her condition improved with corticosteroids.However, chest computed tomography(CT)revealed multiple nodules in both lungs.Third -line carboplatin plus tegafur/gimeracil/oteracil potassium(S-1)was not successful, and fourth- line nivolumab(3mg/kg every 2weeks)was adopted.On day 9 after first administration, she developed fever and radiation recall pneumonitis.Multiple nodules rapidly formed, but they later gradually decreased in number.After 13 courses of nivolumab, the nodules had disappeared completely.Mediastinal lymph nodes decreased in size, but an abdominal lymph node remained enlarged.Nivolumab was continued, and after 24 courses, the abdominal lymph node began to shrink, and the multiple lung metastases continued to disappear.Currently, the best overall response is good partial response to nivolumab.