eP128 - Lymph Node Metastases in Appendiceal Adenocarcinoma: An Analysis from the National Cancer Database

ePoster Presenter(s)

• 

  Shelbi Olson, MD

  General Surgery Resident
  University of Minnesota
  University of Minnesota
  Minneapolis, MN, United States

  All of the relevant financial relationships listed below have been mitigated.
  This individual has no financial relationships with ineligible companies.

Author(s)

• 

  Shreya Gupta, MD

  Fellow
  University of Minnesota
  University of Minnesota
  Cleveland, OH, United States

  All of the relevant financial relationships listed below have been mitigated.
  This individual has no financial relationships with ineligible companies.
• SM

  Sarah Mott, MS

  Biostatistician
  University of Iowa
  Iowa City, Iowa, United States

  Disclosure information not submitted.
• NA

  Niccolo Allievi, n/a

  Consultant General Surgeon
  Papa Giovanni XXIII Hospital
  Bergamo, Lombardia, Italy

  Disclosure information not submitted.
• 

  Lindsay Welton, MD (she/her/hers)

  General Surgery Resident
  University of Minnesota
  University of Minnesota
  Minneapolis, MN, United States

  All relevant financial disclosures have been managed and will be listed below.
  This individual has no financial relationships with ineligible companies.
• IH

  Imran Hassan, MD

  Adjunct Clinical Professor
  University of Iowa
  Cedar Rapids, Iowa, United States

  All relevant financial disclosures have been managed and will be listed below.
  This individual has no financial relationships with ineligible companies.
• 

  Wolfgang Gaertner, MSc, MD, MBA

  Associate Professor and Chief, Division of Colon & Rectal Surgery
  University of Minnesota - M Health
  University of Minnesota
  Minneapolis, Minnesota, United States

  Disclosure information not submitted.

Senior Author(s)

• PG

  Paolo Goffredo, MD

  Assistant Professor
  University of Minnesota
  Minneapolis, Minnesota, United States

  Disclosure information not submitted.

Purpose/Background: Right hemicolectomy represents the standard oncologic procedure for adenocarcinoma of the appendix, providing adequate lymph node (LN) yield for optimal staging. However, a significant proportion of patients have node negative disease on final pathology. Aims of the current study were to determine the rate of LN metastases in appendiceal adenocarcinoma and the associated risk factors from a national cohort of patients.Methods/Interventions: The National Cancer Database (2004-2018) was queried for adults with non-metastatic appendiceal adenocarcinoma who underwent segmental colectomy with curative intent. All patients had a minimum of 12 LN examined and negative surgical margins. Additional exclusion criteria included missing chemotherapy data, radiotherapy, and unclear T and N staging.Results/Outcomes: A total of 3,185 patients were identified. Of those, 25% were aged 70 or above, 53% were male, and 85% white. The majority of patients (77%) had a Charlson-Deyo Comorbidity Score of 0. Most tumors were moderately differentiated (52%), with 28% well differentiated and 21% poorly differentiated. Over half of cancers were non-mucinous at 53%, 39% were mucinous, and 8% had a signet ring cell histology. Median size was 3.3cm (0.0-98.9), and median number of LN examined was 19 (12-90). Most patients were pN0 (76%), while 17% had pN1 and 7% pN2 disease; 21% were stage I, 55% stage II, and 24% stage III. Adjuvant chemotherapy was administered in 43% of cases. On multivariable analysis, factors associated with LN metastasis were moderately (OR 2.1, 95% CI 1.6-2.7) and poorly differentiated (OR 4.7, 95% CI 3.5-6.4), as well as signet ring cell histology (OR 3.4, 95% CI 2.6-4.6; Table 1). Tumor size was not significantly associated with LN metastasis on univariable analysis, and therefore was not included in multivariable analysis. At 60 months, overall survival was 79% for all patients: 89% for Stage I, 83% for Stage II, and 60% for Stage III. Age 70+, male sex, not insured, increasing Charlson-Deyo Score, tumor grade, pathologic T stage, and pathologic N status were independently associated with worse overall survival at 60 months (p < 0.05), whereas adjuvant chemotherapy was associated with better prognosis (single agent: HR 0.75, 95% CI 0.57-0.99; multi-agent: HR 0.73, 95% CI 0.59-0.91).Conclusion/

Discussion: In this US based cohort, 1 out of 4 patients with appendiceal adenocarcinoma was found to have nodal disease at initial presentation. This observation, in association with the clinical relevance of adjuvant chemotherapy, confirms the key role of segmental colectomy in the staging and treatment of these patients. While tumor grade and histology were associated with LN involvement, size was not, suggesting the lack of correlation between tumor biology and cancer dimensions.Factors Associated with Lymph Node MetastasisMultivariable logistic regression of factors associated with LN positivity. pN+ = at least one LN positive on final pathology.