Effect of bone metastasis on efficacy of immune checkpoint inhibitors in treatment of advanced non-small cell lung cancer

Objective To investigate the effect of bone metastasis on the efficacy of immune checkpoint inhibitors (ICI) in treatment of advanced non-small cell lung cancer (NSCLC).

Methods A retrospective analysis was conducted in 248 patients with advanced NSCLC who received ICI therapy. The patients were divided into bone metastasis group (110 cases) and non-bone metastasis group (138 cases) based on the presence of bone metastasis. Clinical characteristics, objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS) were compared between the two groups. The correlations of factors such as bone metastasis with the survival prognosis of NSCLC patients were analyzed using the Cox proportional hazards regression model. A total of 60 treatment-naive NSCLC patients with bone metastasis were selected from research objects, with 30 patients receiving ICI combined with conventional chemotherapy (combination group) and 30 patients receiving conventional chemotherapy alone (chemotherapy group). The therapeutic effects and incidence of treatment emergent adverse events (TEAE) were compared between the two groups.

Results There were no statistically significant differences in ORR and DCR between the bone metastasis and non-bone metastasis groups (P>0.05). The PFS of the bone metastasis group (5.53 months) was shorter than that of the non-bone metastasis group (7.72 months) (χ²=3.674, P=0.045). However, there was no statistically significant difference in OS between the bone metastasis group and the non-bone metastasis group (16.98 versus 17.56 months, χ²=1.333, P=0.248). Multivariate Cox regression analysis showed that bone metastasis was an independent prognostic factor for PFS in NSCLC patients (HR=1.52, 95%CI, 1.10 to 1.98, P=0.003), but not a prognostic factor for OS (P>0.05). The ORR and DCR in the combination group were 43.33% and 93.33%, respectively, which were higher than 26.67% and 76.67% in the chemotherapy group (P < 0.05). The PFS in the combination group was longer than that in the chemotherapy group (χ²=4.023, P=0.036). However, there was no statistically significant difference in OS between the two groups (χ²=1.235, P=0.267). There were no statistically significant differences in the overall incidence of TEAEs or the incidence of ≥grade 3 TEAE between the two groups (P>0.05).

Conclusion Although the occurrence of bone metastasis has an adverse effect on the efficacy of ICI therapy in advanced NSCLC, patients with bone metastasis can still achieve better therapeutic effects through ICI combined with chemotherapy compared with chemotherapy alone.