From McKeown to Ivor Lewis, the learning curve for thoracic lymphadenectomy over the first 100 robotic esophagectomy cases: a retrospective study

BACKGROUND: Lymphadenectomy is an essential but challenging part of the surgical treatment for esophageal cancer. However, the previously reported learning curve for robotic esophagectomy primarily focused on only one surgical approach (McKeown or Ivor Lewis). However, both approaches must be mastered by a mature robotic surgical team to deal with different clinical conditions and satisfy patients’ needs. This study aimed to show how an experienced esophageal surgical team became proficient in both McKeown and Ivor Lewis robotic esophagectomy. METHODS: A retrospective review of the first 100 cases of robot-assisted minimally invasive esophagectomy (RAMIE) by a single surgical team was performed. The cumulative sum (CUSUM) analysis was used to distinguish the change point during the learning course. A subgroup analysis was performed according to a surgical approach (McKeown or Ivor Lewis) to determine the effect of experience from one surgical approach on learning the other RAMIE technique. RESULTS: According to the tendency of the CUSUM plot, the learning curve was divided into four phases. The subgroup analysis indicated the decline of the CUSUM plot in the 3rd phase originated from the start of the Ivor Lewis approach. The attending surgeon took 23 cases to achieve a significant improvement in the number of harvested thoracic lymph nodes using the McKeown approach. Regardless of the acquired experience of McKeown RAMIE, it took another 18 cases for the surgical team to achieve significant improvement in harvesting thoracic lymph nodes using the Ivor Lewis approach. CONCLUSIONS: Twenty-three cases were needed for an experienced surgical team to improve thoracic lymphadenectomy results using McKeown RAMIE. There was another learning phase during the transition from McKeown to Ivor Lewis esophagectomy. Importantly, the acquired experience from performing McKeown RAMIE could shorten how long it takes to learn Ivor Lewis RAMIE.