What happened, in summary

This 80-year-old man, a long-term smoker with good baseline performance status, was evaluated after cough and an abnormal chest X-ray. CT showed a large left lower-lobe lung mass with mediastinal lymphadenopathy and bilateral pleural effusions. PET/CT staged the cancer as Stage IVB squamous non-small cell lung cancer, with spread to contralateral, supraclavicular, and other extra-thoracic lymph nodes. Brain MRI did not show brain metastases. Biopsy confirmed squamous cell carcinoma. PD-L1 expression was very low, with TPS below 1%, and no driver mutations were found. The tumor was notable for abundant tumor-infiltrating lymphocytes, including CD3-positive T cells with both CD4-positive and CD8-positive populations. Because his general condition was good and there was no major organ dysfunction, he started the CheckMate 9LA regimen in September 20XX, combining nivolumab, ipilimumab, carboplatin, and paclitaxel. After the first course, the lung mass had already decreased in size. He continued outpatient immunotherapy after the second course, and by the seventh course the mass had shrunk further to 3.8 cm. Before the eighth course, grade 1 diarrhea and ground-glass opacity led to a 3-week treatment pause. Treatment then resumed as nivolumab alone, and later cycles were tolerated without new major adverse events. The cancer eventually progressed after the 24th cycle of immunotherapy in October 20XX+1. He then continued chemotherapy, but died in November 20XX+2. His course showed an initial partial response despite PD-L1-negative disease, followed by later progression. The same timeline also showed why immune markers beyond PD-L1 may matter in selected patients.