Stage 4 lung cancer: stable disease on immunotherapy combination

What happened, in summary

A 62-year-old woman who had never smoked went to the hospital for kidney stones and had an unexpected lung cancer diagnosis after a full-body examination. She had recently lost weight but otherwise felt well. Chest CT showed a right upper-lobe lung cancer with hilar and mediastinal lymph-node involvement. Echocardiography and contrast imaging found a 5.1 x 3.4 cm metastatic mass in the left atrium, closely associated with the right pulmonary vein, and further imaging showed a right adrenal metastasis and a skull metastasis. Biopsy confirmed non-small-cell lung cancer. The tumor cells were CK-positive, focally CK7-positive, locally TTF-1-positive, locally PD-L1 22C3 TPS-positive, with Ki-67 around 20%; they were negative for NapsinA, P40, P63, CK5/6, and ALK-D5F3. Genetic testing found a TP53 frameshift mutation, a KMT2A mutation, and an MSH2 mutation. Because the cancer had spread to multiple distant sites and was Stage IVB, surgery was not an option. Her physician recommended carboplatin and pemetrexed chemotherapy combined with tislelizumab. During treatment, she reported no significant discomfort, her performance status remained 1, pain score was 1, weight stayed stable, and no major adverse reactions were noted. Tumor shrinkage still required more observation, but her overall condition was stable. She ultimately stopped treatment because of the financial cost and psychological burden of prolonged therapy. Her subsequent cancer status after stopping treatment was not available. No brain parenchymal metastasis was described; the head MRI finding was characterized as a skull metastasis, which is a different category from brain parenchymal involvement. This distinction is clinically important because skull metastasis and brain metastasis carry different implications.