Effect Of Primary Gross Tumor Volume On Prognosis And Treatment Mode Of Upper Thoracic Esophageal Cancer

Objective This study was based on the re delineation of primary tumor volume(GTV-p)of different treatment modes to explore the impact of primary tumor volume on the prognosis and treatment mode of patients with upper thoracic esophageal squamous cell carcinoma(ESCC).Patients and Methods From February 2004 to December 2016,568 patients with upper thoracic esophageal squamous cell carcinoma who received radical treatment in our hospital were collected and retrospectively analyzed,including 238 patients in the surgery[S]group,216 patients in radiotherapy[RT]group and 114 patients in radiotherapy plus surgery[S+RT]group.GTV-p as a continuous variable was entered into the multivariate Cox model using P-splines to determine the optimal cutoff value.Propensity score matching(PSM)analyses were used to adjust the unbalanced characteristics between different subgroups.The clinical features and treatment adverse effects of the different subgroups were compared by Pearson’sχ2 test or Fisher’s exact test.overall survival(OS)and progression-free survival(PFS)rates were calculated using the Kaplan–Meier method,and subgroups were compared using the log-rank test.Cox proportional hazard regression was used for multivariate analysis of clinical characteristics.Results The 5-year OS and PFS were 44.6%and 40.2%respectively.The 5-year OS of S group,RT group and S+RT group were 51.7%,34.2%and 51.0%respectively,and the 5-year PFS were 46.3%,29.0%and 49.6%respectively.GTV-p ranged from 1.85 to 238.99 cm~3,with a median of 19.30 cm~3.P-splines regression confirmed the volume-dependent effect and indicated GTV-p with 30 cm~3 was an optimal cut-off volume for OS and PFS differences.Univariate analysis showed that GTV,gender,c T stage,c N stage,c TNM stage,LNM and tumor length were prognostic factors for OS and PFS of upper thoracic esophageal cancer(P<0.05).Multivariate analysis showed that GTV-p,gender,c T and LNM were independent prognostic factors for OS and PFS.PSM analyses further demonstrated the prognostic value of GTV-p for OS and PFS.As GTV-p was markedly different among S,R,and S+RT groups(P<0.001),we explored the prognostic effect of 3treatment groups stratified by GTV-p.For patients with GTV-p<30 cm~3,no significant survival differences were observed among 3 treatment groups.When GTV-p≥30 cm~3,the 5-year OS rate of RT group and S+RT group was significantly better than that of s group(21.1%and 45.5%vs 14.0%,P<0.05).For PFS,the survival curve of S+RT group was significantly better than that of s group and RT group(5-year PFS rate was 42.8%vs 4.3%and 19.7%,P<0.05).Additionally,S+RT group compared with s group not only did not increase surgical complications,but also compared with RT group significantly reduced the side effects of radiotherapy(P<0.05).Conclusions 30 cm~3 is the best critical value for the difference between the overall survival and progression free survival of gtv-p.GTV-p≥30 cm~3 is an independent prognostic factor for OS and PFS.radiotherapy combined with surgery is the most effective treatment for patients with GTV-p≥30 cm~3.