Adequacy of the national quality forum's colon cancer adjuvant chemotherapy quality metric: Is 4 months soon enough?

Objective: To ascertain whether the National Quality Forum-endorsed time interval for adjuvant chemotherapy (AC) initiation optimizes patient outcome. Background: Delayed AC initiation for stage III colon cancer is associated with worse survival and the focus of a National Quality Forum quality metric (<4 months among patients aged <80 years). Methods: Observational cohort study of patients with stage III colon cancer younger than 80 years within the National Cancer Data Base (2003-2010). The primary outcome was 5-year overall survival evaluated using multivariate Cox proportional hazards regression. Aggregate survival estimates for historical surgery-only controls from pooled National Surgical Adjuvant Breast and Bowel Project trial data were also used. Results: Among 51,331 patients (60.8 ± 11.6 years, 50.2% males, and 77.3% white), 76.3% received standard AC (≤2 months) and 21.6% delayed (>2 and <4 months) AC. Earlier AC was associated with better 5-year overall survival [standard AC, 69.8%; delayed AC, 62.0%; late AC (4-6 months), 51.4%; log-rank, P < 0.001]. The survival rate after late AC was similar to surgery alone (51.1%; Wilcoxon rank sum, P = 0.10). Compared with late AC, standard AC (hazard ratio, 0.62; 95% confidence interval, 0.54-0.72) and delayed AC (hazard ratio, 0.77; 95% confidence interval, 0.66-0.89) significantly decreased risk of death. Risk of death was also lower for standard AC compared to delayed AC (hazard ratio, 0.81; 95% confidence interval, 0.77-0.86). Conclusions: One in 5 patients with stage III colon cancer initiates AC within the National Quality Forum-endorsed interval, but does not derive the full benefit. These data support strengthening current quality improvement initiatives and colon cancer treatment guidelines to encourage AC initiation within 2 months of resection when possible, but not beyond 4 months.