This protocol applies to patients with small cell lung cancer (SCLC) at extensive stage — defined as Stage IV (T any, N any, M1a/b/c), or T3–4 due to multiple lung nodules too extensive or with tumor/nodal volume too large to be encompassed in a tolerable radiation plan. The patient has no localized symptomatic sites and no brain metastases.
Extensive-stage SCLC without brain metastases is treated with combination systemic chemoimmunotherapy — a platinum-based cytotoxic backbone combined with an immune checkpoint inhibitor, administered over multiple cycles. In selected patients, the initial course may be extended beyond four cycles based on response and tolerability, followed by a maintenance immunotherapy phase that continues until disease progression or intolerable toxicity.
The primary aim is to achieve a complete or partial response, or at minimum stable disease, as confirmed by CT imaging assessed after every 2–3 cycles of systemic therapy and at completion of therapy.