Pathologic Responses to Neoadjuvant Chemoimmunotherapy in Primary Limited-Stage Small Cell Lung Cancer

Abstract Background Immunotherapy has been proved its gigiantic influence in extensive-stage small cell lung cancer (ES-SCLC), however, the role of immunotherapy in limited-stage small cell lung cancer (LS-SCLC) is still unkonwn. Methods A retrospective study of 6 patients with LS-SCLC who were treated with neoadjuvant chemoimmunotherapy (durvalumab plus etoposide combined with cisplatin) was performed. Patients were evaluated by the safety, feasibility and pathologic responses of neoadjuvant chemoimmunotherapy. Results Neoadjuvant chemoimmunotherapy was associated with few immediate adverse events and did not delay planned surgery. All patients achieved partial pathologic response (pPR) instead of major pathologic response (mPR) or pathologic complete response (PCR). No association was observed between programmed death-ligand 1 (PD-L1) expression in tumor specimens and the pathologic response. However, tumors with high expression of FoxP3 + regulatory T cells (Tregs) had a better pathologic response than tumors with low expression of FoxP3 + Tregs (Pearson’s r = 0.7280; P = 0.04). Conclusions Neoadjuvant chemoimmunotherapy achieved pPR with few side effects in all resected tumors with LS-SCLC. The FoxP3 + Tregs in tumor microenvironment might play an important role in the chemoimmunotherapy in LS-SCLC.