# Small-cell lung cancer

Source: https://nuclide.cc/indications/sclc/  
Nuclide record `sclc` (Indication). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

A fast-growing lung cancer that responds to chemotherapy then relapses quickly. After 30 years without progress, T-cell engagers and ADCs are finally moving the needle.

## Summary

Small-cell lung cancer is a high-grade neuroendocrine carcinoma, almost always caused by smoking, defined by near-universal loss of TP53 and RB1 and by explosive growth. It presents as extensive-stage disease in two thirds of patients, responds to chemotherapy in most, and relapses in almost all. For three decades the treatment was platinum-etoposide, thoracic radiotherapy for limited-stage disease, prophylactic cranial irradiation, and topotecan at relapse.

The field moved in three steps. First-line chemo-immunotherapy (IMpower133 2018, CASPIAN 2019, ASTRUM-005 2022) added two to five months of median survival and a small tail of long-term survivors. Consolidation durvalumab after chemoradiotherapy for limited-stage disease (ADRIATIC, approved December 2024) was the first curative-intent advance in 30 years, lifting median survival to nearly five years. In relapsed disease, tarlatamab, the DLL3 T-cell engager, became the first drug to beat chemotherapy on overall survival (DeLLphi-304; full FDA approval November 2025), and lurbinectedin plus atezolizumab became the first approved first-line maintenance regimen (IMforte, October 2025).

What is next: maintenance intensification with tarlatamab (DeLLphi-305), the B7-H3 ADC ifinatamab deruxtecan in second line (IDeate-Lung02), alpha-emitting SSTR radioligands (RYZ101), subtype-directed therapy (ASCL1, NEUROD1, POU2F3, inflamed), bispecific and trispecific DLL3 engagers, and the settled question of whether MRI surveillance can replace prophylactic cranial irradiation. Screening remains limited to low-dose CT in smokers, which detects few small-cell cancers early.

## Fields

- Kind: Indication
- Last checked: 2026-09-07
- Tags: lung
- Group: lung
- Burden: Small-cell lung cancer makes up about 15% of lung cancers, roughly 250,000 cases a year worldwide, almost entirely in current or former smokers. Limited-stage disease is treated with curative intent and now with durvalumab consolidation. Median survival is nearly five years in limited-stage and about one year in extensive-stage disease.
- Subtypes: Limited-stage (one hemithorax, ~30%); Extensive-stage (~70%); SCLC-A (ASCL1-driven, DLL3-high; ~50%); SCLC-N (NEUROD1); SCLC-P (POU2F3, tuft-cell-like); SCLC-I (inflamed, IO-responsive); Transformed SCLC (from EGFR-mutant NSCLC under TKI); Combined small-cell / non-small-cell histology
- Biomarkers: DLL3 (not required for tarlatamab); B7-H3; SCLC-A/N/P/I subtypes (research); Stage (limited vs extensive) is the dominant decision; B7-H3 (I-DXd trials); SSTR2 (RYZ101); Transcription-factor subtype (ASCL1/NEUROD1/POU2F3/YAP1, research); PD-L1 and TMB (not predictive in SCLC); SLFN11 (chemotherapy/PARP sensitivity, research); ctDNA (research)

## Standard of care

- Limited stage: Chemoradiation → durvalumab; prophylactic cranial irradiation or MRI surveillance. ([Durvalumab](https://nuclide.cc/drugs/durvalumab/))
- Extensive stage: Platinum-etoposide + atezolizumab/durvalumab; lurbinectedin + atezolizumab maintenance. ([Durvalumab](https://nuclide.cc/drugs/durvalumab/))
- Relapsed: Tarlatamab (preferred), lurbinectedin, topotecan; I-DXd in trials.
- Screening and diagnosis: Low-dose CT screening in heavy smokers finds some SCLC but stage shift is limited; diagnosis by bronchoscopic or CT-guided biopsy; staging with PET/CT and brain MRI. ([CT (computed tomography)](https://nuclide.cc/technologies/ct/), [PET/CT](https://nuclide.cc/technologies/pet-ct/))
- Very limited stage (T1-2 N0, ~5%): Lobectomy with mediastinal node dissection or SBRT, followed by adjuvant platinum-etoposide; PCI or MRI surveillance.
- Limited stage: Concurrent cisplatin-etoposide with thoracic radiotherapy (45 Gy twice daily or 60-70 Gy once daily), then durvalumab consolidation up to 2 years (ADRIATIC); PCI or MRI surveillance. ([Durvalumab](https://nuclide.cc/drugs/durvalumab/))
- Extensive stage, first line: Carboplatin-etoposide plus atezolizumab or durvalumab (4 cycles), then maintenance immunotherapy; lurbinectedin added to atezolizumab maintenance since 2025 (IMforte). Serplulimab-chemotherapy where approved. Consolidative thoracic radiotherapy for residual thoracic disease in good responders. ([Durvalumab](https://nuclide.cc/drugs/durvalumab/))
- Relapsed, platinum-sensitive (≥90 days): Tarlatamab (preferred, OS benefit); platinum-etoposide rechallenge; lurbinectedin; topotecan.
- Relapsed, platinum-resistant (<90 days): Tarlatamab; lurbinectedin; topotecan; clinical trials (I-DXd, RYZ101, DLL3 bispecifics). ([Actinium-225 DOTATATE](https://nuclide.cc/drugs/ryz101/))
- Brain metastases: Whole-brain radiotherapy or, increasingly, stereotactic radiosurgery for limited numbers of lesions; PCI decisions individualised.
- Transformed SCLC (from EGFR-mutant NSCLC): Platinum-etoposide, often with continued EGFR TKI; immunotherapy benefit uncertain; trials.

## State of the art

- Tarlatamab: first OS improvement in relapsed SCLC in decades.
- Immunotherapy consolidation in limited stage.
- Limited-stage: chemoradiation followed by durvalumab consolidation (ADRIATIC), median OS approaching five years.
- Extensive-stage first line: chemo-immunotherapy, now with lurbinectedin-atezolizumab maintenance (IMforte, 2025).
- Relapse: tarlatamab (DLL3×CD3) improved OS over chemotherapy (DeLLphi-304) and received full approval in November 2025.
- B7-H3 ADC ifinatamab deruxtecan and alpha-emitting SSTR radioligand RYZ101 are in phase 3.
- MRI surveillance is displacing prophylactic cranial irradiation while the definitive trial (SWOG S1827) reads out.
- Molecular subtypes (A/N/P/I) explain heterogeneity and are moving toward prospective use.

## Open problems

- Rapid chemoresistance.
- Brain metastases.
- No screening beyond CT for smokers.
- Extensive-stage disease almost always relapses after first-line therapy, so maintenance (lurbinectedin-atezolizumab, tarlatamab) is the current lever; median survival is still barely over a year.
- No validated predictive biomarker for immunotherapy benefit; PD-L1 and TMB do not work in SCLC.
- Sequencing of tarlatamab, I-DXd, lurbinectedin, and platinum rechallenge is untested.
- Cytokine release syndrome and neurotoxicity of T-cell engagers require inpatient step-up dosing that many community centres cannot provide.
- Prophylactic cranial irradiation versus MRI surveillance remains unresolved until SWOG S1827 reads out.
- Transformed SCLC arising from EGFR-mutant NSCLC has no dedicated evidence base.
- Screening rarely catches SCLC early; prevention is tobacco control.
- Trials rarely enrol patients with poor performance status, who are common in this disease.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Small-cell_carcinoma
- NCI PDQ: small cell lung cancer treatment: https://www.cancer.gov/types/lung/hp/small-cell-lung-treatment-pdq
- IASLC: tarlatamab first-line maintenance data: https://www.iaslc.org/iaslc-news/press-release/tarlatamab-anti-pd-l1-first-line-maintenance-after-chemo-immunotherapy-es

## Connected records

- technologies: [CT (computed tomography)](https://nuclide.cc/technologies/ct/), [PET/CT](https://nuclide.cc/technologies/pet-ct/), [Somatostatin receptor PET (68Ga/64Cu-DOTATATE)](https://nuclide.cc/technologies/sstr-pet/), [Targeted alpha therapy](https://nuclide.cc/technologies/targeted-alpha-therapy/)
- targets: [B7-H3](https://nuclide.cc/targets/b7h3/), [CCK2 receptor (gastrin receptor)](https://nuclide.cc/targets/cck2-receptor/), [DLL3](https://nuclide.cc/targets/dll3/), [PARP](https://nuclide.cc/targets/parp/), [Somatostatin receptor 2](https://nuclide.cc/targets/sstr2/)
- companies: [Abdera Therapeutics](https://nuclide.cc/companies/abdera-therapeutics/), [Aktis Oncology](https://nuclide.cc/companies/aktis-oncology/), [Ariceum Therapeutics](https://nuclide.cc/companies/ariceum-therapeutics/), [AstraZeneca](https://nuclide.cc/companies/astrazeneca/), [Bristol Myers Squibb](https://nuclide.cc/companies/bms/), [Evergreen Theragnostics](https://nuclide.cc/companies/evergreen-theragnostics/), [Mariana Oncology](https://nuclide.cc/companies/mariana-oncology/), [Merck & Co. (MSD)](https://nuclide.cc/companies/merck/), [Molecular Targeting Technologies](https://nuclide.cc/companies/molecular-targeting-technologies/), [Telix Pharmaceuticals](https://nuclide.cc/companies/telix/)
- institutions: [Dana-Farber Brigham Cancer Center](https://nuclide.cc/institutions/dana-farber/), [MD Anderson Cancer Center](https://nuclide.cc/institutions/md-anderson/), [Memorial Sloan Kettering Cancer Center](https://nuclide.cc/institutions/mskcc/), [Shandong Cancer Hospital and Institute](https://nuclide.cc/institutions/shandong-cancer-hospital/)
- drugs: [Actinium-225 DOTATATE](https://nuclide.cc/drugs/ryz101/), [Durvalumab](https://nuclide.cc/drugs/durvalumab/)
- indications: [Neuroendocrine and small-cell prostate cancer](https://nuclide.cc/indications/prostate-nepc/), [Non-small cell lung cancer](https://nuclide.cc/indications/nsclc/)
- pathways: [Lineage plasticity & neuroendocrine transformation](https://nuclide.cc/pathways/lineage-plasticity-neuroendocrine/)
- terms: [Neuroendocrine tumour grade (Ki-67) and WHO classification](https://nuclide.cc/terms/net-grade-ki67/)
- trials: [A Study of [177Lu]Lu-DOTA-TATE in Newly Diagnosed ES-SCLC Patients in Combination With Carboplatin, Etoposide and Atezolizumab](https://nuclide.cc/trials/nct05142696/), [Study of [212Pb]Pb-DOTAM-MAM279 ([212Pb]Pb-MP0712) in Patients With Small Cell Lung Cancer and Other DLL3 Expressing Solid Tumors](https://nuclide.cc/trials/nct07278479/)
- opportunities: [DLL3 imaging for small-cell lung cancer](https://nuclide.cc/opportunities/opp-dll3-imaging-sclc/)

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