Patients
Esophageal cancer patients who underwent transmediastinal esophagectomy or transthoracic esophagectomy with gastric conduit reconstruction via the posterior mediastinal route between January 2010 and December 2014 at the University of Tokyo Hospital were candidates for this study. All these patients were staged preoperatively using esophagogastroduodenoscopy with biopsies and computed tomography scans. Transmediastinal esophagectomy was performed using a robotic surgical system as described in our previous clinical study verifying the safety and utility of robotic transmediastinal esophagectomy [7]. The indications for transthoracic or transmediastinal esophagectomy are (1) histologically proven esophageal cancer, (2) sufficiently good general condition to tolerate conventional open esophagectomy, and (3) a tumor clinically staged as T1-3 N0-1 M0 according to the 7th edition of the American Joint Committee on Cancer tumor-node-metastasis (TNM) classification. In addition, written informed consent to undergo robot-assisted surgery without receiving financial support from the national health insurance system was required for transmediastinal esophagectomy. The QOL survey was performed after excluding those of the above-described patients who met the following exclusion criteria: (1) patients who had a recurrent lesion or who were under treatment for other malignancies; (2) patients who had a history of surgeries of another malignancy; (3) patients who had undergone a reoperation because of complications after esophagectomy. Between January 2010 and December 2014, 128 esophageal cancer patients underwent transthoracic esophagectomy or transmediastinal esophagectomy. Of the 128 patients, 17 patients had died before this study began, 18 patients developed disease recurrence, and 2 patients had a history of reoperation for postoperative complications after esophagectomy. According to the exclusion criteria, consequently, 64 patients, 26 transmediastinal esophagectomy patients, and 38 transthoracic esophagectomy patients, were subjects in the present study, in which we assessed the QOL scores of post-esophagectomy patients and compared the transmediastinal esophagectomy and the transthoracic esophagectomy group scores. This study was approved by The University of Tokyo’s institutional review board. All study participants provided informed consent, and all 64 patients gave their consent.
Surgical methods
The robot-assisted transmediastinal esophagectomy with three-field lymphadenectomy was performed in three stages, all with the patient in the supine position. In the first stage, lymph node dissections in the cervical and the abdominal fields were performed simultaneously by two surgical teams. The cervical procedure was performed via a collar incision under mediastinoscopic guidance. The abdominal procedure was performed via a laparoscopic approach. In the second stage, the robotic surgical device, da Vinci S (Intuitive Surgical, Sunnyvale, CA, USA), was brought in to perform the transhiatal robotic procedure through the abdominal ports. In the dissections consisting of the cervical procedure via the collar incision and the da Vinci procedure via the transhiatal approach, the entire esophagus as well as dissected mediastinal lymph nodes was freed from adhesions and attachments. Upon completion of the mediastinal dissection, the da Vinci S robotic system was moved away from the surgical field. The last stage included the harvest of surgical specimens, reconstruction with a gastric tube conduit, and cervical anastomosis.
Transthoracic esophagectomy patients underwent a right anterolateral thoracotomy via the fourth intercostal space with two- or three-field lymphadenectomy and intrathoracic anastomosis. The creation of the gastric conduit was performed by the same procedure as that performed in the transmediastinal esophagectomy: a gastric conduit with a diameter of 4 cm was created with linear staplers. Pyloroplasty was performed by the same procedure in both transthoracic esophagectomy and transmediastinal esophagectomy. The posterior mediastinal route was used with only one exception, and the anastomosis was performed using a 25-mm circular stapler.
Quality of life measurement
The cross-sectional QOL survey evaluated patients at intervals of more than 3 months since their esophagectomy or the last administration of chemotherapeutic agents from October 2014 to September 2015. Patients who met the above criteria were asked to participate in this study on their regular follow-up visit. The participants were given a self-administered questionnaire and were asked to send it back by mail after filling out the queries.
Patients’ quality of life was assessed using the validated European Organization for Research and Treatment of Cancer Quality of Life Core Questionnaire (EORTC QLQ-C30) [8] as well as the esophageal site-specific module (EORTC QLQ-OES18) [9]. The EORTC QLQ-C30 consists of the patient’s global health status, five functional scales (physical, role, emotional, cognitive, and social functioning), three symptom scales (fatigue, pain, and nausea and vomiting) and six single-item measures (dyspnea, insomnia, appetite loss, constipation, diarrhea, financial difficulties). It can assess functional aspects of QOL and symptoms that commonly occur in patients with cancer. The EORTC QLQ-OES18 consists of nine symptom scales (eating, reflux, pain, trouble swallowing saliva, choking when swallowing, dry mouth, trouble with taste, trouble with coughing, and trouble speaking), and was designed to assess patients treated for esophageal cancer by procedures including esophagectomy, chemoradiation, endoscopic palliation, or palliative chemotherapy and/or radiotherapy. High scores in the global health status and the function scales represent a higher level of function and enhanced global health status. On the other hand, higher scores in symptom scales represent more severe symptoms. The reliability and validity of the Japanese version of the EORTC QLQ-C30 and OES-18 have been demonstrated [10, 11].
Statistical analysis
All statistical analyses were performed using JMP 11.0 (SAS Institute Inc. Cary, NC, USA). Wilcoxon’s rank-sum test was used for the analysis of group differences and Fisher’s exact test was used for the proportional differences. A P value less than 0.05 was considered statistically significant.