Stage IVA lung cancer with small-cell and adenocarcinoma components: mixed response before infection halted treatment

What happened, in summary

This 71-year-old Chinese man had a smoking history and was admitted in August 2023 with a lung lesion known for 2 years and 1 month of back pain. He also had hypertension, diabetes, hyperuricemia, prior coronary stenting, and prior laryngeal cancer surgery. Imaging found masses in the right upper lung and left lower lung, enlarged mediastinal and bilateral hilar lymph nodes, and destructive bone lesions involving C2, T10, and sacral vertebrae. Right-lung CT-guided biopsy showed a poorly differentiated lung tumor with small-cell markers: TTF-1, PCK, CK8/18, CD56, Syn, CgA, and INSM1 were positive, and Ki-67 was 70%. The diagnosis was Stage IVA small cell lung cancer, T2aN3M1b. Tumor markers included elevated CEA, NSE, CYFRA21-1, and ProGRP. Treatment began with radiation to painful left rib disease, 3000 cGy in 10 fractions, followed by etoposide plus carboplatin with dose reductions because of thrombocytopenia, leukopenia, diarrhea, and appetite loss. Durvalumab was added from the third chemotherapy session and then continued as maintenance. In February 2024, the right lung tumor had partially responded, but the left lung mass progressed. In March 2024, pleural effusion developed; pleural fluid and left-lung biopsy showed lung adenocarcinoma, CK7/TTF-1/Napsin A-positive, PD-L1 TPS less than 1%, and no obvious mutation target. Treatment then included anlotinib, pemetrexed plus carboplatin, pemetrexed consolidation, and later right-lung radiation. The right lung lesion again partially responded, and the left lung remained stable. Severe lung infection and respiratory failure then forced suspension of anticancer treatment despite the earlier attempts to control both histologic components.