All the statistical analyses were performed using SPSS version 16.0 software (SPSS Inc., Chicago, IL, USA). Overall survival (OS) was determined as the time (in months) between the 1st day of therapy and the last follow-up or the date of death. Progression-free survival (PFS) was calculated from the date of CCRT initiation to the date of documented failure (local recurrence or metastasis occurrence) or the date of the last follow-up for those still alive. Survival curves were determined using the Kaplan–Meier method. Given that a small portion of our raw data (<5%) was considered as missing data, we imputed these missing data with mean substitution. Predictive factors of survival were analyzed by a univariate analysis and further evaluated by multivariate Cox regression analysis to estimate the hazard ratio with 95% confidence interval (CI). All statistical analyses were performed with a two-sided significance value of 0.05.
Patients and tumor characteristics
A total of 82 patients were eligible for analysis. Clinical baseline characteristics are detailed in Table 1. The mean age was 76.41 years, ranging from 70 to 87 years. Sixty-seven patients were male and 15 were female, with a sex ratio of 4.5:1.0; majority of patients (76.8%) had a good ECOG PS score (0–1). Approximately 36.6% patients had a severe dysphagia ≥2, and 30.5% had an initial weight loss >10% in 6 months. The median Charlson score was 2, and the most common comorbidity for this cohort was hypertension (n=37). Diabetic (30.5%) and peripheral vascular or cerebrovascular disease (12.2%) were ranked second and third in the data.
Detailed tumor characteristics before treatment are listed in Table 2. There were mainly T3–4 stage tumors (92.7%) and squamous cell carcinoma (n=74, 90.2%). Approximately 69.5% (n=57) patients were recorded with stage III–IV tumors with tumor locations as follows: upper-third (19/82, 23.1%), middle-third (37/82, 45.1%), and lower-third (13/82, 15.9%). A majority of tumors were more than 5 cm in length (72.0%).
Treatment compliance and tumor response to CCRT
All patients completed the first cycle of chemotherapy. Three patients refused the second cycle of chemotherapy, one patient developed refractory peritonitis during treatment and the other two got fever after occurrence of grade 4 leukopenia and grade 3 thrombocytopenia. These patients also gave up radiation. Eleven (13.4%) patients required dose reduction in the second cycle of chemotherapy for hematological toxicity, and the actual dose of PTX and CDDP was reduced to 105 and 25 mg/m2, respectively. Approximately 71 (86.6%) patients completed radiation, including four patients with radiation delay. A total of 66 (80.5%) patients finished CCRT on schedule, including 55 (67.1%) patients in whom treatment regimen was not changed.
A total of 81 patients were eligible for response evaluation, which was done after 4 weeks following the last radiotherapy session. Twenty-nine patients were considered to have had a complete response (CR), resulting in a 35.8% CR rate, and 25 patients experienced no treatment effect (including 18 stable diseases and seven in progression). At the end of the last follow-up, 55 patients experienced disease recurrence. Primary recurrent sites included the following: 34 locoregional and local residual disease, 15 distant, and six in both sites.