Survival and prognostic factors of lung cancer patients with preexisting connective tissue disease: a retrospective cohort study

Abstract

Background: Connective tissue diseases (CTDs) are a group of special commodities in lung cancer (LC). This study aimed to analyze the survival and prognostic factors of LC patients with preexisting CTDs.

Methods: A total of 84 LC patients with preexisting CTDs that presented at Peking Union Medical College Hospital (PUMCH) were retrospectively recruited in this study between January 2000 and June 2017. Patient survival was compared using the Kaplan-Meier method. Univariate and multivariate Cox proportional hazard models were used to assess prognostic variables.

Results: Of the 84 LC patients, 36 (41.8%) had underlying rheumatoid arthritis (RA), 20 (23.8%) had idiopathic inflammatory myopathy (IIM), 18 (21.4%) had Sjögren syndrome (SS), 6 (7.1%) had systemic sclerosis (SSc), and 4 (4.8%) had systemic lupus erythematosus (SLE). The median overall survival (OS) was 21 months (IQR, 8-72 months), and the 1-, 3-, and 5-year survival rates were 61.3%, 36.7%, and 29.5%, respectively. The survival rates between different CTD subgroups, histopathologies, and disease stages were significantly different (P<0.05). Multivariate analysis showed that the independent prognostic factors for OS were IIM [hazard ratio (HR), 3.61; 95% confidence intervals (CI), 1.69-8.21; P=0.002], SS (HR, 2.72; 95% CI, 1.01-7.33; P=0.048), and radical resection (HR, 0.11; 95% CI, 0.04-0.35; P<0.001).

Conclusions: Different CTD subtypes and the radical resection of LC are closely related to patient prognosis. This indicates a need for both identifications of CTD types and active treatment strategies for LC.

Keywords: Lung cancer; connective tissue disease (CTDs); prognostic factors; survival.

Figure 1

Flow chart of inclusion criteria, exclusion criteria, and follow-up of LC patients with preexisting CTDs. CTD, connective tissue disease; LC, lung cancer; IIM, idiopathic inflammatory myopathy; RA, rheumatoid arthritis; SS, Sjögren syndrome; SSc, systemic sclerosis; SLE, systemic lupus erythematosus.

Figure 2

Comparisons of LC-CTD intervals between the five CTD groups. CTD, connective tissue disease. LC, lung cancer; IIM, idiopathic inflammatory myopathy; RA, rheumatoid arthritis; SS, Sjögren syndrome; SSc, systemic sclerosis; SLE, systemic lupus erythematosus. **P<0.01; ****P<0.0001.

Figure 3

Survival curves. (A) Survival curve for LC patients with all CTDs; (B) survival curves for LC patients according to the five CTD subgroups; (C) survival curves for LC patients according to surgical-pathological stages; (D) survival curves for LC patients according to the two major histopathological subgroups; (E) comparison of survival between epithelial tumors. LC, lung cancer; CTD, connective tissue disease; OS, overall survival; IIM, idiopathic inflammatory myopathy; RA, rheumatoid arthritis; SS, Sjögren syndrome; SSc, systemic sclerosis; SLE, systemic lupus erythematosus.

Figure 4

Survival curves of different treatments. (A) Comparison of survival curves for early stage LC-CTD patients with/without radical resection. (B) Comparison of survival curves for late-stage LC-CTD patients with/without chemotherapy. (C) Comparison of survival curves for late-stage LC-CTD patients with/without targeted therapy. (D) Comparison of survival curves for late-stage LC-CTD patients with/without radiotherapy. LC, lung cancer; CTD, connective tissue disease; IIM, idiopathic inflammatory myopathy; RA, rheumatoid arthritis; SS, Sjögren syndrome; SSc, systemic sclerosis; SLE, systemic lupus erythematosus. The early stage is defined as stage I-IIIa LC. Late-stage is defined as stage IIIb to IV LC.