Lung Cancer: Small Cell

Key points

• Small cell lung cancer: usually CENTRAL, arising from APUD cells (amine precursor uptake and decarboxylation) — hence its neuroendocrine paraneoplastic syndromes.
• Ectopic ADH → SIADH with hyponatraemia · ectopic ACTH → bilateral adrenal hyperplasia, with high cortisol causing a hypokalaemic alkalosis · Lambert-Eaton myasthenic syndrome from antibodies to voltage-gated calcium channels.
• Usually metastatic at the time of diagnosis, and it is the most rapidly progressive lung cancer.
• Very early stage disease (T1-2a, N0, M0) may be considered for surgery — NICE NG122 supports this in carefully selected patients.
• Limited-stage disease: combination chemotherapy with concurrent thoracic radiotherapy · consider prophylactic cranial irradiation in those who respond.
• Extensive-stage disease: platinum-based chemotherapy, now combined with immunotherapy in eligible patients · palliative radiotherapy for local symptoms.

Decision points in this pathway

• Very early stage disease (T1-2a, N0, M0)?
• Limited-stage disease?

The full step-by-step algorithm, including what to do at each branch, opens in the app for approved members.