361. PROGNOSTIC EFFECT OF POSITIVE RADIAL MARGIN AFTER MACROSCOPIC TUMOR CLEARANCE IN ESOPHAGECTOMY FOR ESOPHAGEAL SQUAMOUS CELL CANCER

Abstract

<p>Background</p><p>Complete resection is linked to better survival for esophageal squamous cell cancers. The definition of positive margin depends on the pathologic reporting system used. Despite precise definitions by pathological examination, the concept of residual disease from involved radial margin is not clearly understood surgically. No actual barrier exists between the thoracic esophagus and surrounding structures like the pleura, trachea and aorta. Cancer cells are commonly detected at the radial margin even after precise anatomical dissection of the primary tumor away from adjacent structures. This study aims to investigate the prognostic impact of positive radial margin after macroscopic tumor clearance(R1).</p><p>Methods</p><p>In a single tertiary center between 2002 and 2020, patients who underwent three-phase esophagectomy for pT3/ypT3 esophageal squamous cell cancer were studied. Only histologically-proven R0/RM+ resections were included, proximal/distal margin involvement and R2 disease were excluded. Clinicopathological data was analyzed from a prospectively managed database. <strong>Positive radial margin</strong> is defined as: in <strong>Analysis I</strong>—cancer found within 1 mm of the radial margin (close-R1); in <strong>Analysis II</strong>—microscopic involvement of the radial margin (true-R1). The rate and pattern of recurrence and overall survival of R0 resections were compared with close- or true-R1.</p><p>Results</p><p>Of 97 patients, in <strong><em>Analysis I:</em></strong> R0&<strong>close-R1</strong> resection were achieved in 37(38.1%) & 60(61.9%) patients; & in <strong>Analysis II:</strong> R0&<strong>true-R1</strong> were 82(84.5%) & 15(15.4%) patients. Patient demographics, neoadjuvant therapy & pTNM-stages were not different between R0 & either <strong>close</strong>/<strong>true-R1</strong> resections.</p><p>Local recurrence rate with R0 patients was not statistically different from <strong>close-R1</strong> (29.7%vs.48.3%,p = 0.071); it was significantly lower when compared with <strong>true-R1</strong> patients (35.4vs.73.3%,p = 0.006). All <strong>true-R1</strong> patients with disease recurrence developed local recurrence (n = 11).</p><p>Overall median survival was not significantly different when R0 patients were compared to <strong>close-R1</strong> (158.6vs.93.9 months,p = 0.076). Similarly this was not different between R0 & <strong>true-R1</strong> (139.1vs.75.8 months,p = 0.599).</p><p>Conclusion</p><p>When only pT3/ypT3 tumors were studied, <strong>true-R1</strong> margin better-stratified patients who would develop local recurrence. Overall survival with R0 resections were better although statistically insignificant, regardless of the definition of radial R1 margin.</p>