The global incidence of esophageal cancer has increased in the past decades [1
], and it has one of the highest malignant potentials of any type of tumor. As per the data of the American Joint Committee on Cancer, the postoperative 5-year survival rate of stage I esophageal cancer is about 90%, and decreases to 45% for stage II, 20% for stage III, and only 10% for stage IV patients [3
]. Although the effectiveness of extended lympadenectomy for esophageal cancer remains to be demonstrated by randomized prospective studies, better survival was obtained after 3-field lymph node dissection than 2-field lymph node dissection in Japan [4
]. Three-field lymph node dissection, including dissection of cervical, mediastinal, and abdominal lymph nodes, is the standard procedure employed for surgically curable esophageal cancer located in the middle or upper thoracic esophagus in Japan. The majority of Western surgical groups differ with Japanese groups on their strategy for surgical management of esophageal carcinoma. Many investigators in Europe and the United States have reported that the results of concurrent chemoradiotherapy are comparable to those of surgery [6
]; however, most of the surgical procedures in such studies are not as radical as the Japanese standard procedures, and the overall survival rate after surgery is lower than that of the Japanese standard. Nevertheless, some Western surgeons have asserted the importance of radical lymph node dissection [8
Extended lympadenectomy is extremely invasive and leads to high operative morbidity, particularly because of pulmonary complications [5
]. Since the first report of thoracoscopic esophagectomy by Cuschieri et al. [10
] in 1992, the adoption of minimally invasive esophagectomy has increased in many countries [11
]. Minimally invasive esophagectomy might minimize injury to the chest wall and is believed to reduce surgical invasiveness. Moreover, several reports have indicated its feasibility and curative efficacy [12
]. Although the incidence of minimally invasive surgery is increasing in Japan, only 20% of esophagectomies performed in 2009 were conducted using a minimally invasive approach [16
]. Three-field lymphadenectomy is the standard surgical method employed in Japan; the same degree of lymph node dissection must be performed even for a minimally invasive esophagectomy. Minimally invasive surgery is used less often for esophagectomy, considering the technical challenges of esophagectomy accompanied by extensive lymphadenectomy, which is the Japanese standard surgical method.
Although thoracoscopic esophagectomy has been promoted due to its minimal invasiveness, another distinctive advantage of minimally invasive esophagectomy is the magnifying effect of the thoracoscope, as very small structures can be clearly identified. Thus, the surgery can be performed with more precision, preserving the nerves and vessels.
It has still not been clearly demonstrated whether minimally invasive surgery is associated with lower morbidity and mortality. Furthermore, the oncologic outcomes after minimally invasive surgery are still controversial. Hence, a prospective randomized study of open versus minimally invasive surgery is needed. However, although the incidence of esophageal cancer is increasing, and it is among the 10 most common cancers worldwide, few patients are candidates for potentially curative resection. In addition, a prospective randomized study would be difficult to complete within a reasonable timeframe. Because the technique of minimally invasive surgery is not standardized, even in high volume centers, it is very difficult to set up multi-institutional studies.