Stage 3 squamous cell lung cancer: complete remission on tislelizumab monotherapy

What happened, in summary

A 73-year-old man was admitted in February 2023 with paroxysmal cough, sputum, chest pain, weight loss, and exertional asthma. CT showed a right upper-lobe lung mass, and PET-CT found an irregular 4.1 × 3.5 cm spiculated lesion with increased FDG uptake, tiny nearby nodules, and enlarged lymph nodes in stations 10R, 4R, and 2R. CT-guided biopsy confirmed right lung squamous cell carcinoma. Immunohistochemistry supported the diagnosis, including P40 positivity and TTF-1 negativity, with Ki-67 of 75%. PD-1/PD-L1 testing was not performed. He was staged as cT2bN2M0, Stage III. Because of age, tumor size, femoral head necrosis, and other health issues, surgery and radiation were not selected. On March 14, 2023, he started tislelizumab, paclitaxel liposome, and carboplatin every 3 weeks. Severe thrombocytopenia occurred, so the regimen was dose-adjusted in April. In May, bacteremia and herpes zoster led to a treatment pause while he received anti-infective and antiviral therapy. CT on May 29 showed the solid component of the right upper-lobe tumor had largely disappeared, and the response was classified as partial remission. He received a second combination cycle in June. Because of chemotherapy-related marrow suppression and pre-existing heart and kidney dysfunction, he and his family declined further chemotherapy. He then received tislelizumab alone in September and November 2023. After a 5-month treatment break, April 2024 imaging showed collapsed cord-like changes where the cystic lesion had been, no brain metastases on MRI, smaller lymph nodes, and markedly lower CSSA, CEA, NSE, and CYFR21-1 levels. The response was assessed as complete remission by iRECIST.