Immunohistochemistry and Radiomic Features for Survival Prediction in Small Cell Lung Cancer

Background Aim of the study was to evaluate the role of different immunohistochemical and radiomics features in patients with small cell lung cancer (SCLC). Methods Consecutive patients with histologically proven SCLC, with limited n=47 (48%) or extensive disease n=51 (52%), treated with radiotherapy and chemotherapy at our department, were included in the analysis. The expression of different immunohistochemical markers from the initial tissue biopsy such as CD56, CD44, chromogranin A, synaptophysin, TTF-1, GLUT-1, Hif-1 a, PD-1 and PD-L1 and MIB-1/KI-67 as well as the LDH und NSE from the initial blood sample were evaluated. H-Scores were additionally generated for CD44, Hif-1a and GLUT-1. A total of 72 computer tomography (CT) radiomics texture features, from a homogenous subgroup (n=31) of patients, were correlated with the immunohistochemistry, the survival (OS) and the progression free survival (PFS) Results The median OS, calculated from diagnosis, was 21 months for patients with limited disease and 13 months for patients with extensive disease. The expression of synaptophysin correlated with a better OS (HR 0.546 95% CI 0.308-0.966, p=0.03). The expression of TTF-1(HR 0.286, 95% CI: 0.117-0.698, p=0.006) and a lower GLUT-1 H-score (median = 50, HR: 0.511, 95% CI: 0.260-1.003, p=0.05) correlated with a better PFS. Patients without chromogranin A expression had a higher incidence for cerebral metastases (p=0.02) and patients with PD 1 expression had a higher incidence of distant metastases (p=0.02) at diagnosis. Our radiomics analysis did not reveal a single texture feature that correlated highly with OS or PFS. Correlation coefficients ranged between -0.48 and 0.39 for OS and between -0.46 and 0.38 for PFS. Conclusions The role of synaptophysin should be further evaluated, as synaptophysin-negative patients might profit from treatment intensification. We report an at most moderate correlation of radiomics features with overall and progression free survival and no correlation with the expression of different immunohistochemical markers.