ABSTRACT
Objective To investigate the value of 18 F-fluorodeoxyglucose FDG) positron emission tomography (PET)-computed tomography (CT) in predicting the progression-free survival (PFS)and overall survival (OS) of patients with esophageal squamous cell carcinoma (ESCC) after threedimensional (3D) radiotherapy.Methods A retrospective analysis was performed on 98 ESCC patients,who underwent FDG PET-CT before 3D radiotherapy from 2004 to 2010,to investigate their 1-,3-,and 5-year PFS and OS rates.The relationship of maximum standard uptake value (SUVmax),mean SUV (SUVmean),metabolic target volume (MTV),length of primary tumor on PET-CT before radiotherapy,and number of tumors on PET with PFS and OS were analyzed.The SUVs and clinical data were analysed by independent samples t-test or Hotelling T2 test; the Kaplan-Meier method was used for calculating PFS and OS rates,and the Logrank test was used for survival difference analysis;the prognostic factors were analysed using the Cox proportional hazard model.Results The follow-up rate was 100％ ;56 patients were followed up for at least 3 years,and 27 for at 5 years.The SUVmax SUVmean and MTV of primary tumor,length of primary tumor on PET-CT before radiotherapy,and number of tumors on PET were correlated with PFS and OS (x2 =8.99-41.82,all P ＜ 0.01).The Cox regression analysis showed that PFS could be well predicted based on SUVmean (x2 =4.41,P =0.036,RR =1.398) and number of tumors on PET (x2 =6.79,P =0.009,RR =3.650) and that OS could be well predicted based on number of tumors on PET (x2 =5.03,P =0.025,RR =3.740).Conclusions When estimating the long-term response to precise radiotherapy in patients with ESCC,SUV mean and number of tumors on PET may be used to predict PFS,and number of tumors on PET may be used to predict OS.