Variation in Number of Lymph Nodes Assessed in Colorectal Cancer Resection: Surgeon, Pathologist, Or Hospital?
Hari Nathan*1, Andrew D. Shore1, Robert a. Anders2, Susan L. Gearhart1, Timothy M. Pawlik1
1Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD; 2Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD
Introduction: American Society of Clinical Oncology / National Comprehensive Cancer Network quality guidelines recommend the examination of ≥12 lymph nodes (LN) following colorectal cancer (CRC) resection. Compliance with this 12-LN standard may be a function of patient, surgeon, pathologist, or hospital factors. We sought to identify factors associated with adherence to the 12-LN guideline to better inform targeting of quality improvement (QI) efforts.Methods: SEER-Medicare data (1998-2002) were used to identify patients with Medicare Part A and Part B coverage undergoing a first CRC resection. The treating surgeons, pathologists, and hospitals were also identified. Multilevel mixed-effects logistic regression was used to evaluate adherence to the 12-LN standard.Results: Study criteria identified 31,815 eligible patients with median age 76 years, of whom 54% were female. Most patients had colon tumors (80%). CRC surgery was performed by a general surgeon in most cases (79%), and less commonly by a colorectal surgeon (13%) or other specialist (8%). The majority of patients were treated at teaching hospitals (54%), and 23% were treated at ACOSOG-participating hospitals. A median of 10 LN were evaluated per patient, and only 41% of patients had ≥12 LN examined. In the multivariable model (Table), predictors of increased adherence to the 12-LN standard included colon vs. rectal primary, resection by a colorectal vs. general surgeon, treatment at a teaching or ACOSOG hospital, and hospital CRC resection volume. Notably, neither surgeon nor pathologist case volume was associated with 12-LN examination. Of the variation in guideline compliance that was not explained by the factors in the model or by other patient-related factors, 82% was hospital-related, 17% pathologist-related, and 1% surgeon-related.Conclusions: Adherence to the 12-LN standard for CRC resection is poor. Non-compliance is largely attributable to differences among hospitals and pathologists rather than variation among surgeons. QI efforts should be targeted at underperforming hospitals.
Predictors of Adequate Lymph Node Assessment
| Variable | Odds Ratio | 95% Confidence Interval | P-Value |
| Age (per decade) | 0.94 | 0.91 — 0.97 | 0.001 |
| Female vs. male | 1.19 | 1.13 — 1.25 | < 0.001 |
| Year of operation (per year) | 1.10 | 1.08 — 1.12 | < 0.001 |
| Colon vs. rectum | 1.60 | 1.50 — 1.71 | < 0.001 |
| Colorectal vs. general surgeon | 1.11 | 1.00 — 1.22 | 0.04 |
| Teaching hospital | 1.29 | 1.13 — 1.48 | < 0.001 |
| ACOSOG hospital | 1.48 | 1.22 — 1.80 | < 0.001 |
| Surgeon case volume (per 10x ↑) | 1.07 | 0.99 — 1.17 | 0.09 |
| Pathologist case volume (per 10x ↑) | 0.98 | 0.88 — 1.08 | 0.6 |
| Hospital case volume (per 10x ↑) | 1.19 | 1.03 — 1.37 | 0.02 |
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