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Impact of Mediating and Confounding Variables on the Volume–Outcome Association in the Treatment of Pancreatic Cancer

  • Pancreatic Tumors
  • Published:
Annals of Surgical Oncology Aims and scope Submit manuscript

Abstract

Background

High-volume centers (HVC), academic centers (AC), and longer travel distances (TD) have been associated with improved outcomes for patients undergoing surgery for pancreatic adenocarcinoma (PAC). Effects of mediating variables on these associations remain undefined. The purpose of this study is to examine the direct effects of hospital volume, facility type, and travel distance on overall survival (OS) in patients undergoing surgery for PAC and characterize the indirect effects of patient-, disease-, and treatment-related mediating variables.

Patients and Methods

Using the National Cancer Database, patients with non-metastatic PAC who underwent resection were stratified by annual hospital volume (< 11, 11–19, and ≥ 20 cases/year), facility type (AC versus non-AC), and TD (≥ 40 versus < 40 miles). Associations with survival were evaluated using multiple regression models. Effects of mediating variables were assessed using mediation analysis.

Results

In total, 19,636 patients were included. Treatment at HVC or AC was associated with lower risk of death [hazard ratio (HR) 0.90, confidence interval (CI) 0.88–0.92; HR 0.89, CI 0.86–0.91, respectively]. TD did not impact OS. Patient-, disease-, and treatment-related variables explained 25.5% and 41.8% of the survival benefit attained from treatment at HVC and AC, reducing the survival benefit directly attributable to each variable to 4.9% and 6.4%, respectively.

Conclusions

Treatment of PAC at HVC and AC was associated with improved OS, but the magnitude of this benefit was less when mediating variables were considered. From a healthcare utilization and cost–resource perspective, further research is needed to identify patients who would benefit most from selective referral to HVC or AC.

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Funding

Research reported herein was supported in part through funding from the John Wayne Cancer Foundation (Costa Mesa, CA, USA).

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Authors and Affiliations

  1. Department of Surgery, Brooke Army Medical Center, Fort Sam Houston, TX, USA

    Phillip M. Kemp Bohan MD, Elizabeth L. Carpenter MD, Alexandra M. Adams MD & Timothy J. Vreeland MD

  2. Center for Cardiovascular Analytics, Research and Data Science (CARDS), Portland, OR, USA

    Shu-Ching Chang PhD & Gary L. Grunkemeier PhD

  3. Department of Surgery, William Beaumont Army Medical Center, Fort Bliss, TX, USA

    Holly V. Spitzer DO & Daniel W. Nelson DO

Authors
  1. Phillip M. Kemp Bohan MD
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  2. Shu-Ching Chang PhD
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  3. Gary L. Grunkemeier PhD
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  4. Holly V. Spitzer DO
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  5. Elizabeth L. Carpenter MD
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Correspondence to Daniel W. Nelson DO.

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Kemp Bohan, P.M., Chang, SC., Grunkemeier, G.L. et al. Impact of Mediating and Confounding Variables on the Volume–Outcome Association in the Treatment of Pancreatic Cancer. Ann Surg Oncol 30, 1436–1448 (2023). https://doi.org/10.1245/s10434-022-12908-z

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  • DOI: https://doi.org/10.1245/s10434-022-12908-z

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