Abstract: Objective  To analyze the correlation of heat shock protein 70(Hsp70) and imaging parameters of 18F-fluorodeoxyglucose-positron emission tomography(18FDG-PET) with the prognosis of early-stage limited-disease small cell lung cancer(LD-SCLC). 
Methods  A total of 57 patients with early-stage LD-SCLC and 57 healthy people(NC group) were enrolled to analyze the relationship of Hsp70 and imaging parameters, including metabolic tumor volume(MTV), maximum standardized uptake values(SUVmax), mean standardized uptake values(SUVmean), and integrated standardized uptake values(iSUV), with the prognosis of LD-SCLC. 
Results  The gastrin releasing peptide precursor, neuron-specific enolase, lactate dehydrogenase, Hsp70, MTV, SUVmax, SUVmean and iSUV in patients with early LD-SCLC were higher than those in healthy people(P＜0.05). Hsp70, MTV and iSUV had high sensitivity and specificity in the early diagnosis of LD-SCLC. The lung cancer specific survival(LCSS) rate and disease progression-free survival rate(DFS) in the Hsp70≥3.24 μg/L subgroup were lower than those in the Hsp70 ＜3.24 μg/L subgroup(P＜0.05). The 5-year overall survival(OS) and PFS were higher in MTV ＜64.63 cm3 subgroup than in the MTV≥64.63 cm3 subgroup(P＜0.05). The 5-year overall survival(OS) and LCSS rate were higher in the iSUV ＜316.78 subgroup than in the iSUV≥316.78 group(P＜0.05). Cox model regression analysis showed that clinical stage, gastrin releasing peptide precursor, neuron-specific enolase, Hsp70, MTV and iSUV were independent risk factors for the prognosis of early LD-SCLC. 
Conclusion  MTV, iSUV and Hsp70 are closely related to the prognosis of early LD-SCLC patients undergoing early surgery, radiotherapy and chemotherapy treatment. A larger sample size is recommended in future clinical research.

Key words: small cell lung caancer, heat shock protein 70, chemoradiotherapy