MP56-16: Surgical Management of Clinically Localized Urachal Carcinoma: Evaluating the Role of Lymphadenectomy as Standard of Care

Kyle Rose*, Erica Roberts, Heather Huelster, Andrew Chang, Logan Zemp, Alice Yu, Michael Poch, Roger Li, Phillippe Spiess, Scott Gilbert, Wade Sexton, Tampa, FL

Introduction: Diverse practice patterns exist in the management of urachal carcinoma (UC). Case series involving this malignancy remain relatively small, precluding evidence-based revisions to clinical practice. Our aim was to utilize a large national dataset to better understand clinical and pathologic factors impacting oncologic outcomes and the role of lymphadenectomy.

Methods: The National Cancer Database (NCDB) was queried for patients with pure adenocarcinoma histology (8140, 8480, 8481, 8490) at expected UC locations (C67.1, C67.3, C67.7). Patients were excluded if there was metastatic disease (cN+M+), incomplete tumor staging or unavailable tumor size. The primary outcome was overall survival (OS) stratified by pathologic tumor and node characteristics. The secondary outcome was the presence of pathologically positive lymph node disease (pN+) based on primary tumor size. Survival data was estimated with Kaplan-Meier method, and evaluated using Log-rank test.

Results: After screening, 629 patients were identified in the NCDB with cN0M0 UC. Median patient age was 59.0 years, and median tumor size was 4.0 cm. Surgical margins were positive in 61 of 516 (12%) patients who had complete margin status documented. Lymphadenectomy was performed at the time of surgery in 326 (52%) patients, of whom 66 (20%) had pN+ disease. Death occurred in 329 (52%) patients, with a median OS of 73 months (95% CI 67.8-79.4). The results of the OS analysis are shown in Table 1. Tumor size >5cm contributed to a lower OS (63 vs. 77.2 months, p=0.05). The incidence of pN+ cancer increased with primary tumor size (Table 2).

Conclusions: High rates of positive surgical margins and lymph node positive disease advocate for wide surgical excision and routine lymphadenectomy as standard of care in patients with UC. Despite excluding patients with cN+M+ UC, study limitations include the presence of surgeon selection bias for lymphadenectomy.

Source of Funding: none