***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: We found no randomised controlled trials on this topic. We included six non-randomised studies (five retrospective) that compared laparoscopic versus open transhiatal oesophagectomy (334 patients: laparoscopic = 154 patients; open = 180 patients); five studies (326 patients: laparoscopic = 151 patients; open = 175 patients) provided information for one or more outcomes. Most studies included a mixture of adenocarcinoma and squamous cell carcinoma and different stages of oesophageal cancer, without metastases. All the studies were at unclear or high risk of bias; the overall quality of evidence was very low for all the outcomes. The differences between laparoscopic and open transhiatal oesophagectomy were imprecise for short-term mortality (laparoscopic = 0/151 (adjusted proportion based on meta-analysis estimate: 0.5%) versus open = 2/175 (1.1%); RR 0.44; 95% CI 0.05 to 4.09; participants = 326; studies = 5; I² = 0%); long-term mortality (HR 0.97; 95% CI 0.81 to 1.16; participants = 193; studies = 2; I² = 0%); anastomotic stenosis (laparoscopic = 4/36 (11.1%) versus open = 3/37 (8.1%); RR 1.37; 95% CI 0.33 to 5.70; participants = 73; studies = 1); short-term recurrence (laparoscopic = 1/16 (6.3%) versus open = 0/4 (0%); RR 0.88; 95% CI 0.04 to 18.47; participants = 20; studies = 1); long-term recurrence (HR 1.00; 95% CI 0.84 to 1.18; participants = 173; studies = 2); proportion of people who required blood transfusion (laparoscopic = 0/36 (0%) versus open = 6/37 (16.2%); RR 0.08; 95% CI 0.00 to 1.35; participants = 73; studies = 1); proportion of people with positive resection margins (laparoscopic = 15/102 (15.8%) versus open = 27/111 (24.3%); RR 0.65; 95% CI 0.37 to 1.12; participants = 213; studies = 3; I² = 0%); and the number of lymph nodes harvested during surgery (median difference between the groups varied from 12 less to 3 more lymph nodes in the laparoscopic compared to the open group; participants = 326; studies = 5). The proportion of patients with serious adverse events was lower in the laparoscopic group (10/99, (10.3%) compared to the open group = 24/114 (21.1%); RR 0.49; 95% CI 0.24 to 0.99; participants = 213; studies = 3; I² = 0%); as it was for adverse events in the laparoscopic group = 37/99 (39.9%) versus the open group = 71/114 (62.3%); RR 0.64; 95% CI 0.48 to 0.86; participants = 213; studies = 3; I² = 0%); and the median lengths of hospital stay were significantly less in the laparoscopic group than the open group (three days less in all three studies that reported this outcome; number of participants = 266). There was lack of clarity as to whether the median difference in the quantity of blood transfused was statistically significant favouring laparoscopic oesophagectomy in the only study that reported this information. None of the studies reported post-operative dysphagia, health-related quality of life, time-to-return to normal activity (return to pre-operative mobility without caregiver support), or time-to-return to work. There are currently no randomised controlled trials comparing laparoscopic with open transhiatal oesophagectomy for patients with oesophageal cancers. In observational studies, laparoscopic transhiatal oesophagectomy is associated with fewer overall complications and shorter hospital stays than open transhiatal oesophagectomy. However, this association is unlikely to be causal. There is currently no information to determine a causal association in the differences between the two surgical approaches. Randomised controlled trials comparing laparoscopic transhiatal oesophagectomy with other methods of oesophagectomy are required to determine the optimal method of oesophagectomy.
Output:

Randomised controlled trials are the best types of studies to find out whether one treatment is better than another since it ensures that similar types of people receive the new and the old treatment. But we did not find randomised controlled trials; we identified six relevant non-randomised studies with a total of 334 patients, which compared laparoscopic and open surgeries. Since one of the studies did not provide usable results, five studies, with 326 patients, provided information for this review; laparoscopic surgery = 151 patients and open surgery = 175 patients. In four of these studies, historical information was collected from hospital records. In one study, new information was collected. In general, new information is considered to be more reliable than information from hospital records. The differences between laparoscopic and open transhiatal oesophagectomy were imprecise for: deaths during the short-term and long-term, the percentage of people with major complications, narrowing of the new junction between the gut, created after removing the oesophagus, cancer returning during the short-term and long-term, and the proportion of people who required blood transfusion. The proportion of patients with any complications and the average lengths of hospital stay were less in the key-hole group than the open cut group. There was lack of clarity about the difference in the amount of blood transfused between the two groups. None of the studies reported difficulty in swallowing after surgery, health-related quality of life, the amount of time it took to return to normal activity (same mobility as before surgery), or work. The quality of the evidence was very low. This was mainly because it was not clear whether participants who received laparoscopic surgery were similar to those who had open surgery. This makes the findings unreliable. Well-designed randomised controlled trials are necessary to obtain high-quality evidence on the best method to perform oesophagectomy.