Pattern Of Nodal Recurrence In Locally Advanced Siewert Type Ⅱ And Ⅲ Adenocarcinoma Of Gastroesophageal Junction After Curative Resection And Its Implication On The Lymphatic Target Volume Design

Objective To investigate the recurrence pattern and distritution of nodal relapse in patients with locally advanced Siewert type Ⅱ and Siewert type Ⅲ adenocarcinoma of the gastroesophageal junction (AGE) after curative resection, and to provide evidence to the clinical target volume (CTV) delineation of elective lymph node irradiation.Methods From January 2009 to December 2013, we retrospectively reviewed the clinical data of patients with adenocarcinoma of the gastroesophageal junction (AGE) in our institute, inclusion criteria includes:(1) curative resection, (2) histopathologically diagnosed with locally advanced AGE (T3/4 or any N+), (3) Siewert type Ⅱ and Siewert type Ⅲ defined by endoscopy, upper gastroenterography, macroscopic examination during the course of the operation, or recordings of gross tumor from pathologist, (4) no history of radiotherapy, (5) confirmed of node recurrence in follow-up CT images and all the recurrence sites were clearly and fully displayed. First regional recurrence was recorded and two diagnostic radiologists with specialty of gastrointestinal tract independently investigated. All epicenters of recurrent LNMs were registered proportionally by referencing the surrounding landmarks onto simulation computed tomography images of a standard patient. A 3-dimensional (3-D) coordinate system was established to quantify the extent of LNM distribution.Results Seventy eight patients meet the enrolled criteria. The median recurrence time was 10 months (1～48 months), and 90% of the recurrence was observed within 2 years after the surgery. The lymph nodes with highest risk of recurrence were No.l6b1 (38.5%), No.16a2 (37.2%), No.9 (29.5%) and No. 11p (25.6%), respectively. Following were No.16b2 (20.5%), No.7 (19.2%) and No.8 (19.2%). No difference was observed between Siewert types (Type Ⅱ vs Type Ⅲ) in different nodes stations (P=0.090-1.000). For non-N3 patients, the most frequent recurrence sites were No.11p, No.16b1, No.16a2, No.9, No.8 and No.7; and for N3 patients, the most commonly involved recurrent nodes were No.16b1, No.16a2, No.9, No.16b2, No.11p and No.7. Patients with N3 disease had higher risk of failure at No.16 station than those with non-N3 disease (66.7% vs 33.3%, P=0.004; OR=4.00,95% CI:1.54-10.37) and involved lower station (No.16b2). The distribution of LNMs were mapped to display 3-D recurrence model and possible boundaries of CTV with satisfying coverage were identified.Conclusions The most prevalent nodal recurrence in patients with Siewert type Ⅱ and Siewert type Ⅲ AEG after curative resection was around the abdominal aorta and the celiac bifurcation. N3 patients had higher risk of relapse at No.16 station than non-N3 patients. Inclusion of the above vessel basin and consideration of N status in target delineation of AEG type Ⅱ and Ⅲ patients is suggested.