Paraneoplastic neurological syndrome and its impact on the treatment outcomes of small-cell lung cancer: A single-center retrospective analysis

Introduction: Paraneoplastic neurological syndrome (PNS) is associated with small-cell lung cancer (SCLC). However, the frequency and characteristics of PNS and the efficacy of anticancer treatment for these patients have not been investigated in the Japanese/Asian population previously. Therefore, we aimed to better understand PNS by evaluating real-world data from patients with PNS complicated by SCLC.

Methods: Patients diagnosed with Stage II-IV SCLC at a single center between August 2007 and April 2021 were retrospectively analyzed. The primary outcome was the incidence of PNS. The secondary outcomes were the change in performance status (PS) after treatment commencement and outcomes following anticancer treatment, including objective response rate (ORR), progression-free survival (PFS), and overall survival (OS).

Results: A total of 318 patients were evaluated; PNS was present in 2.8% (n = 9) of the overall population. All patients with PNS exhibited poor Eastern Cooperative Oncology Group PS (≥2); moreover, 78% of patients had a PS score of 3-4. An improvement in PS was observed in 56% (n = 5) of patients. Patients with PNS exhibited treatment efficacies similar to patients without PNS (ORR: 89% vs. 83%, p = 1.0; PFS: 7.6 vs. 5.7 months, p = 0.69; OS: not reached vs. 15.6 months, p = 0.23).

Conclusions: A total of 2.8% of patients had SCLC complicated by PNS, with poor PS observed. However, anticancer therapy led to an improvement in PS and comparable ORR, as well as PFS and OS similar to those observed in patients without PNS. Thus, anticancer therapy should be considered in patients with PNS.