In this study, we retrospectively analyzed the data of 419 patients with ESCC at a single cancer center in Xinjiang area, which is one of the high-risk regions for esophageal cancer in China. The results showed that the adjuvant therapy for majority of patients were insufficiency by conducting postoperative therapy analyses. In addition to tumor stage, the regions of patients and nationality were also an independent prognostic factor. In further subgroup analysis, we confirmed that nationality was the main factor affecting the prognosis of patients from rural areas.
Our finding that ESCC patients had poor survival and our statistics indicating a lack of postoperative treatment revealed that multidisciplinary treatments, especially adjuvant therapy were essential for patients. Our results also revealed that the future management of these patients from rural area needed to be enhanced with further long-term follow-up data to support clinical decisions and interventional strategies. All of these will have a significant impact on the prognosis of patients by influencing the doctor's follow-up strategy.
In our study, most of them were male and over 60 years old. This is consistent with the results of epidemiological investigations that carcinomas of the esophagus in China occur mainly in people aged 60–74 years and the incidence of EC in men was twice as many as that in women’ . In our study, only about 23.6% of the patients were diagnosed with early stage 0 or 1 ESCC, and most of the patients were in middle or late stage. Our stage results are also consistent with the findings from other studies [12, 13]. It has been acknowledged that morbidity of ESCC in the Kazakh population in Xinjiang was far higher than other ethnic minorities . In our study, a worser prognosis was observed in Kazakh patients with ESCC. This is consistent with other study.
Additionally, in our multivariate analysis, we found that the source of patients is an important factor affecting the prognosis. This is in agreement with the previously reported data [7, 15, 16]. Kou et al. analyzed the possible reason for this discrepancy in their finding may lie in the difference of socioeconomic status (SES) disparities in the populations. Our results of subgroup analysis suggested that Kazakh patients from rural area even had a shorter prognosis than other populations living in the same area. This suggest that more attention should be paid to the sources of patients during clinical treatment.
In addition, our results suggested that the adjuvant therapy for majority of patients were insufficiency. The treatment of ESCC depends on the characteristics of the patient including health status and TNM stage. Current guidelines suggest additional treatment of patients with ≥ T2 tumors, although the risk of node-negative T2 lesions is low . The characteristics of esophageal resection alone can be considered (< 2 cm and well-differentiated), but most subjects with esophageal cancer was locally advanced (> T2 and / or N+) when they were diagnosed . For these patients, to reduce primary tumor bulk chemotherapy, radiotherapy or chemo-radiotherapy isessential. Since about 87% of our patients were in middle or late stage, adjuvant therapy was recommended for most of them according to EC guidelines ; however, only 165 subjects received post-surgery treatments. Noticeably, we found that several patients did not receive complete postoperative treatment either for that they lived far from the hospital or for the side effects of the treatment. Our follow-up results revealed that postoperative management of patients with esophageal squamous cell carcinoma needs to be strengthened.
Our results showed that the 1-, 3-, and 5-year OS rates of this patients with ESCC were 84.8%, 47.5%, and 37.3%, which was worse than that was reported in a previous study . In our univariate analysis of the overall survival of the 419 patients, tumor length, nerve invasion, vascular cancer embolus, sources of patients, nationality, tumor differentiation, tumor stage, lymph node metastasis, stage of disease and pathological type were related to OS. The association with tumor length, pT category, pN category, and TNM stage were consistent with the results of other studies [20–22]. It is accepted that smoking and drinking alcohol can increase the risk of ESCC from the results of a meta-analysis . However, in our study, age, history of smoking, using thoracoscopy and region of patients were unrelated to their OS. Insufficient adjuvant therapy, diet or environmental factors may lead to lower OS. Therefore, they interferes with other prognostic factors. Some studies showed that older age was a prognostic factor [12, 13]. In our univariate analysis, age was not related to OS. Owing to improvements in surgical safety, age is less of a risk factor for the prognosis of ESCC. What's more, one of our findings disaccorded with others was that the OS of patients with a family history of cancer was longer than the OS of those with no history. This may be due to more active screening and treatments are conducted by patients with a family history of cancer.
This study has some limitations. It is a single institution, retrospective study. The retrospective nature of this study may undermine its power. However, our cancer center is the largest in Xinjiang, which is one of the high-risk regions for esophageal cancer in China. So we believe that our data may provide a better understanding of ESCC in Xinjiang. Until now, few large cohort studies focused on postoperative adjuvant therapy of ESCC in Xinjiang, our results will be useful for the whole management of esophageal cancer. Of course, further follow-up studies are required to confirm our findings and develop new therapeutic strategies for these patients.