The 2026 World Conference on Lung Cancer (WCLC) brought the global thoracic oncology community to Seoul, South Korea from September 12–15. This year's theme, "Science Without Boundaries: Uniting the World Against Thoracic Cancer," was particularly fitting for small cell lung cancer (SCLC). Data from two exciting phase 3 clinical trials were discussed as part of the conference’s plenary sessions and we saw scientific progress across every part of the patient journey.
Here are the conference highlights, organized by limited-stage (LS) and extensive-stage (ES) disease.
Limited-Stage SCLC
Can we protect the brain without irradiating it? Yes
Prophylactic cranial irradiation (PCI) is given to protect patients with LS-SCLC from the development of future brain metastasis, but it can lead to cognitive side effects. The SWOG S1827/MAVERICK trial asked whether brain MRI surveillance alone could replace PCI. In the study, participants were randomized to receive either PCI or MRI brain surveillance. At 12 months, 17% of patients who received MRI surveillance were alive without cognitive decline versus 6% of those given PCI. Though brain metastases were more common without PCI, preliminary survival between the two groups was similar, and serious side effects were far lower in the group receiving MRI surveillance (0.8% vs 7.9%). The study redefines how LS-SCLC is treated and demonstrates that MRI surveillance should be the preferred approach.
Could surgery return for stage II–III disease? Maybe
A phase 2 study of neoadjuvant serplulimab (an immune checkpoint antibody targeting the PD1 protein) plus chemotherapy enrolled 45 patients with stage IIB–IIIB (N2) disease. Of the 40 patients that had surgery, 40% had no remaining cancer at surgery (pathologic complete response). Blood testing for ctDNA (circulating tumor DNA) helped tell the complete story. Patients who saw the levels of ctDNA drop before surgery had a 66.7% complete response rate, versus 15.4% for those who did not have ctDNA levels drop, suggesting that adding a treatment regimen before surgery, such as neoadjuvant chemo-immunotherapy, may be a possibility for LS-SCLC. However, these findings need to be confirmed in randomized trials.
A companion study looked at why some LS-SCLC tumors develop resistance to this approach and continue to grow. In resistant tumors, two types of specialized immune cells, CXCL9+ dendritic cells and CXCR3+ regulatory T-cells clustered together and dampened the immune attack. Blocking CXCR3 slowed tumor growth in mice, suggesting that targeting CXCR3 could reverse this immune resistance and make the treatment more effective.
Does screening find SCLC earlier? Highly possible
A multicenter analysis from the University of Illinois and MD Anderson challenged the currently held belief that SCLC grows too fast for lung cancer screening to help. Among 294 patients with LS-SCLC, those diagnosed through lung cancer screening had higher survival rates suggesting that lung cancer screening may help catch SCLC at earlier stages and offer better outcomes to patients.
Extensive-Stage and Relapsed SCLC
Are B7-H3 antibody-drug conjugates effective in treating ES-SCLC? Yes
The biggest SCLC news came during the plenary sessions discussing data from two clinical trials of antibody-drug conjugates (ADCs) targeting B7-H3. B7-H3, also called CD276, is a protein produced by many cells in the body. It binds to receptors on cancer-fighting T-cells. Cancer cells are known to co-opt this interaction to avoid detection by the immune system by making large amounts of B7-H3 protein. Both trials compared the ADCs to topotecan, a chemotherapy, after first-line treatment.
In the TAISHAN-302 phase 3 trial, the ADC, tambotatug pelitecan, improved survival to 13.3 versus 9.4 months, with strong activity in treating brain metastases. In ARTEMIS-008, risvutatug rezetecan, another ADC targeting B7-H3, improved survival to 18.5 versus 10.3 months. Both ADCs caused fewer severe side effects than the chemotherapy, topotecan, though lung inflammation caused by these ADCs needs monitoring. These two studies suggest that ADCs have the potential to become a new second-line standard of care for ES-SCLC. A biomarker study supported the use of the target, B7-H3, by showing it was expressed broadly across all SCLC subtypes. It is important to note that both trials enrolled only patients in China and the results need to be confirmed in other populations.
Combinations may push B7-H3 ADCs further. In the phase 1b/2 BNT324-01 study, pumitamig, a bispecific antibody that simultaneously binds to the PD-L1 and the VEGF-A proteins, combined with the B7-H3 ADC elfetabart drozuntecan (elfe-D) shrank tumors in 70.4% of patients with SCLC.
Is it becoming easier to administer tarlatamab? Yes
The T-cell engager, tarlatamab, that binds to the DLL3 protein on SCLC and the CD3 protein on T cells, has now become standard of care for treating ES-SCLC. The medicine is typically given as an infusion through a vein (using an IV). The DeLLphi-308 study tested an under-the-skin (sub-cutaneous) injection. This more convenient route of administration matched IV medicine exposure, produced only mild cytokine release syndrome (a side effect commonly associated with tarlatamab), and allowed some patients to skip post-dose monitoring.
Are we developing new ways to direct the immune system against ES-SCLC? Yes
We are developing other approaches to target the DLL3 protein that is produced in high quantities by SCLC. A treatment called LB2102, a DLL3-targeted CAR-T-cell therapy, produced a 28.6% response rate in a small study of 20 patients who had received multiple prior lines of treatment. Importantly, no severe cytokine release syndrome (CRS) was observed. This is important to note given that severe CRS is a common side effect in CAR-T-cell therapy.
Looking Beyond the Tumor
A survey conducted by Lung Cancer Europe found 66.2% of people affected by SCLC reported a negative impact on their mental health after the SCLC diagnosis. However, 59% were never offered any form of mental health support. Mental health is an important component of quality of life and mental health services should be offered as part of survivorship discussions with people living with SCLC.
Looking Ahead
WCLC 2026 showed SCLC care moving toward more options, fewer side effects, and treatment matched to each tumor's biology. Stay tuned for our highlights from the 2026 European Society of Molecular Oncology (ESMO) conference for more updates on the progress in SCLC research.