Background: Adequate nodal harvest (≥12 lymph nodes) in colorectal cancer has been shown to optimize staging and has been proposed as a quality indicator of colorectal cancer care. We previously demonstrated a population-based improvement in adequate nodal harvest over time, particularly with the use of an audit and feedback strategy. The goal of this current study is to evaluate the impact of improved adequate nodal harvest on 3 relevant clinical outcomes: node positivity rate, use of adjuvant chemotherapy, and survival.
Methods: This current population-based study included all patients undergoing resection for primary stage I-III colorectal cancer in Nova Scotia, Canada, from January 1, 2001 to December 31, 2005. Linkage of the provincial cancer registry with other administrative databases (hospital discharge data, physician claims data, and national census data) provided clinical, demographic, diagnostic, treatment event, and survival data. The association between increase in adequate node harvest and relevant clinical outcomes was examined for all patients and in a subgroup analysis of patients who received care in a health district that used audit and feedback to improve nodal harvest.
Results: Among the 2,250 patients, the median nodal harvest was 8, and the overall node positive rate was 35.9%. Despite significant improvement in the proportion of patients undergoing adequate nodal harvest over time (P<.0001), no significant change was observed in the node positivity rate (P=.51), proportion of patients undergoing adjuvant chemotherapy (P=.83), or survival (P=.25). In the subgroup analysis confined to patients where audit and feedback was used to improve nodal harvest rates, clinical outcomes were not improved.
Conclusions: Although improvements in the rate of adequate nodal harvest did occur over time, no corresponding meaningful improvement in clinical outcomes was noted. Given the need that quality indicators not only be associated with outcome, but also that outcome improves as such indicators are optimized, this study questions the inclusion of a nodal harvest≥12 lymph nodes as a quality indicator of colorectal cancer care.