Early Stage Lung Cancer Detection in Systemic Sclerosis Does Not Benefit Survival

A recent study published in the journal PLOS One reports the results of a comprehensive clinical assessment review in patients with Systemic sclerosis and lung cancer.

Systemic sclerosis (SSc) is a connective tissue disorder characterized by immune dysregulation and accumulation of extracellular matrix constituents resulting in organ dysfunction with pulmonary involvement, eventually leading to SSc-related mortality. Patients with SSc have a 3–4 fold greater risk of developing lung cancer, with males having a higher standardized incident ratio than females.

Prior studies of SSc-associated lung cancer have identified the presence of the Scl-70 antibody and interstitial lung disease (ILD) as potential risk factors for lung cancer. However, radiographic abnormalities and details of pulmonary function testing (PFTs) are lacking research.

In order to provide the first description of the immunohistochemical and molecular profile of SSc associated lung cancers, in the study entitled “Early Stage Lung Cancer Detection in Systemic Sclerosis Does Not Portend Survival Benefit: A Cross Sectional Study”, Jeremy Katzen from the Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine in Chicago and colleagues conducted a review of patients with SSc that also had lung cancer. They collected clinical, radiographic, and detailed pathologic data from the Northwestern Memorial Healthcare Electronic Data Warehouse (EDW), an electronic repository of health data. Risk factors and cancer characteristics were compared with the National Cancer Institute SEER Cancer Statistics (NCI SEER) data.

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A total of 17 patients with SSc and lung cancer were identified. Results showed that an 88% prevalence of lung cancers were diagnosed after the onset of SSc. A total of 65% of the patients were also found to be tobacco users. Results from the Serologic tests revealed that 50% of the cases were Scl-70 positive, and that 12 cases had radiographic evidence of SSc lung involvement. Only 6 had limiting physiology on the tests of pulmonary function. A total of 13 cases had pulmonary nodules prior to lung cancer, and of these 13 were adenocarcinoma.

A total of 10 patients had molecular mutational examination and the researchers found that 1/10 had EGFR mutation and 2/8 had KRAS mutation. More of the non-small cell lung cancers were diagnosed at localized disease (56%) than in the NCI SEER database. However, 5-year survival among the stage I cases was 25% versus 54% of expected survival.

Based on the results, the researchers concluded that their method resulted in a high identification of adenocarcinomas. They also found that lung cancers were diagnosed at an early stage, however this did not confer a survival advantage. A high proportion of patients who developed lung cancer had interstitial lung disease.