Comparison of the incidence of skeletal related events (SREs) between non small cell lung cancer (NSCLC) and small cell lung cancer (SCLC)

Aim/Background

The aim of the current study was to evaluate the difference of incidence of SREs between NSCLC and SCLC.

Methods

This study was a retrospective cohort study. Consecutive patients pathologically proven NSCLC or SCLC between 2003 and 2012 in our hospital were reviewed. Patients treated with systemic chemotherapy were included in this study, and in terms of NSCLC patient confirmation of EGFR mutaiton status was required. SREs were defined as (1) pathologic fracture or (2) spinal cord cpmpression or (3) radiation or surgery to bone.

Results

A total of 229 patients (NSCLC: 168, SCLC: 61) were included in this study. Patietns characteristics with NSCLC and SCLC were as follows, NSCLC; median age: 65 years (range 34-87), male/female: 102/66, bone metastasis at initial diagnosis present/absent: 62/106, adenocarcionma/non-adenocarcinoma: 143/25, EGFR mutaion positive/negative 65/103. SCLC; median age 69 years (range 50-83), male/female: 51/10, bone metastasis at initial diagnosis present/absent: 13/48. The cumulative incidence of prophylactic use of bone targeting agents were 19% (32/168) and 4% (3/61) in NSCLC and SCLC patients, respectively. The incidence of patients who developed at least one SREs were 25% in NSCLC (42/168 patients) and 10% in SCLC patients (6/61 patients) (p < 0.05). In NSCLC patients, there was no difference of the incidence of patients who developed at least one SRE between EGFR mutaion positive group and negative group. Multivariate analysis with logistic regression model revealed NSCLC (Odds Ratio [OR]: 3.1, 95% CI: 1.01-7.66) and bone metastasis at initial diagnosis (OR: 8.29, 95% CI: 3.91-16.93) were independent unfavorable facotors for SREs. In terms of SREs observed at initial diagnosis in patients with bone metastasis, NSCLC patients showed high incidence of SREs compared to SCLC patients (39% vs. 8%, p < 0.05). Repeatedly, in NSCLC patients, there was no difference of the incidence of SREs observed at initial diagnosis between EGFR mutaion positive group and negative group. Time to first SRE of SCLC was significantlly longer than that of NSCLC (p < 0.05).

Conclusions

The incidence of SREs was lower in patients with SCLC compared to those with NSCLC.

Clinical trial identification

This study does not have clinical trial identification because of its retrospective design.

Disclosure

All authors have declared no conflicts of interest.