***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: From 2667 references, we identified two randomized studies, in six reports, that included 431 participants. All participants were clinically staged to have at least T3 and/or node positive thoracic esophageal carcinoma, 93% of which was squamous cell histology. The risk of methodological bias of the included studies was low to moderate. High-quality evidence found the addition of esophagectomy had little or no difference on overall survival (HR 0.99, 95% CI 0.79 to 1.24; P = 0.92; I² = 0%; two trials). Neither study reported PFS, therefore, freedom from loco-regional relapse was used as a proxy. Moderate-quality evidence suggested that the addition of esophagectomy probably improved freedom from locoregional relapse (HR 0.55, 95% CI 0.39 to 0.76; P = 0.0004; I² = 0%; two trials), but low-quality evidence suggested it may increase the risk of treatment-related mortality (RR 5.11, 95% CI 1.74 to 15.02; P = 0.003; I² = 2%; two trials). The other pre-specified outcomes (quality of life, treatment-related toxicity, and use of salvage procedures for dysphagia) were reported by only one study, which found very low-quality evidence that use of esophagectomy was associated with reduced short-term QoL (MD 0.93, 95% CI 0.24 to 1.62), and low-quality evidence that it reduced use of salvage procedures for dysphagia (HR 0.52, 95% CI 0.36 to 0.75). Neither study compared treatment-related morbidity between treatment groups. Based on the available evidence, the addition of esophagectomy to chemoradiotherapy in locally advanced esophageal squamous cell carcinoma, provides little or no difference on overall survival, and may be associated with higher treatment-related mortality. The addition of esophagectomy probably delays locoregional relapse, however, this end point was not well defined in the included studies. It is undetermined whether these results can be applied to the treatment of adenocarcinomas, tumors involving the distal esophagus and gastro-esophageal junction, and to people with poor response to chemoradiation.
Output:

We included two randomized studies, in six published reports, with 431 participants with locally advanced esophageal cancer. We searched biomedical databases, clinical trial registries, conference proceedings, and reference lists up to 7 February 2017 for studies. The quality of evidence ranged from very low to high, depending on the outcome being assessed, because the trials were small and at unclear or high risk of bias (a systematic error or deviation from the truth that affects the results, favouring one treatment over another). We found evidence that adding surgery reduced the risk of the cancer recurring at the primary site, but did not improve overall survival. Moreover, there were more treatment-related deaths in the group of participants who underwent surgery.