PhD Scientific Days 2021

CL_III_L: Clinical Medicine III. Lectures

New Insights Into the Site-specific Metastasis Pattern of Small Cell Lung Cancer

Text of the abstract

Introduction: Lung cancer is the leading cause of cancer-related mortality. Although the presence of organ metastases is a major factor for unfavorable prognosis in small cell lung cancer (SCLC), our current understanding of the mechanisms and resulting patterns of SCLC dissemination is limited.

Aims: The aim of our study was to investigate the metastasis pattern of SCLC with regards to organ specificity and timing of the blood-borne metastases in a comprehensive large cohort of patients diagnosed with SCLC.

Methods: In this retrospective non-interventional study of 1009 Caucasian SCLC patients, we investigated the correlation between the distinct locations of primary tumor and metastatic sites during disease progression. Endoscopically visible primary SCLCs were defined as central, otherwise as peripheral tumors.

Result: The most commonly affected organs were the liver, the brain and the bones. The onset of bone (p<0.001), brain (p<0.001) and pericardial (p=0.02) metastases were late events, whereas adrenal gland (p=0.005) and liver (p<0.001) metastases occurred earlier during tumor progression. When comparing central and peripheral tumors, no significant differences were found in the distribution of early versus late metastases. By subsequent analysis, we found that patients with bone metastases had a higher than expected likelihood of having liver metastases, whereas brain metastases tended to appear together with adrenal gland metastases. As for intrathoracic metastases, pleural, lung and pericardial metastases also appeared more frequently together than expected. In secondary exploratory analyses, we found that patients with central primary tumors have decreased median overall survival (OS) compared to those with peripheral tumors, although this tendency does not appear to be statistically significant (p=0.078). As for the number of metastases, as expected, patients with at least one metastatic site at diagnosis exhibit significantly worse OS than those with no metastasis (p<0.0001).

Conclusion: This comprehensive large cohort study demonstrates metastatic site- and sequence-specific variations in patients with SCLC. A better understanding of metastasis distribution patterns might help to improve patient selection and treatment in this devastating disease.

University and Doctoral School

Semmelweis University, Károly Rácz Doctoral School of Clinical Medicine