Remarkable response to PD-1 inhibitor in a patient with extensive-stage small cell lung cancer: a case report and literature review

Abstract

We report a case of a 59-year-old male diagnosed with extensive-stage small cell lung cancer (SCLC). He received first-line platinum doublet chemotherapy and second-line topotecan-based regimen, but experienced disease progression after each line of therapy. He was then treated with Sintilimab, a PD-1 inhibitor, in combination with nab-paclitaxel in the third-line setting, which resulted in significant tumor shrinkage. Restaging scans showed a partial response per RECIST criteria with 62% reduction in tumor burden. This case highlights the application and efficacy of immune checkpoint inhibitors in extensive-stage SCLC.

Keywords: CEA; NLR; PD-1; immune checkpoint inhibitors; small cell lung cancer.

Figure 1

Treatment timeline.

Figure 2

Imaging changes during treatment. CT images demonstrating diagnosis, treatment responses, and progression. [(1, 2) Small cell lung cancer was first diagnosed (December 2021), CT scan showed a 3.8×2.2cm pulmonary nodule and brain metastases. (3). Minimal lung lesions during first-line chemotherapy (February 2022), CT scan showed a 0.8×1.4cm pulmonary nodule. (4). Progression after completion of first-line chemotherapy (May 2022), CT scan showed a 1.3×1.7cm pulmonary nodule. (5). Progression after completion of second-line chemotherapy (September 2022), CT scan showed a 2.1×1.6cm pulmonary nodule. (6). Partial remission was achieved after immunotherapy (February 2023), CT scan showed a 0.9×0.5cm pulmonary nodule).