A Modified Textbook Outcome (mTO) Results in Superior Outcome for Patients with Stage III Colon Cancer

Keywords: Colon cancer, adjuvant chemotherapy

Synopsis: Textbook Outcome (TO) is a composite multidimensional measure of desired short-term quality metrics following an operation. It represents the ideal or “textbook” postoperative outcome. However, for high-risk colon cancer patients, long-term outcomes are also dependent on receipt of adjuvant therapy, which TO does not consider. Thus, we propose a modified TO (mTO) concept, one that incorporates adjuvant therapy. We assessed the impact of mTO on OS for patients with stage III colon cancer.

Methods: The National Cancer Database was queried to evaluate 225,842 patients diagnosed with Stage III colon cancer between 2004 - 2017 and underwent resection. TO was defined as achieving negative margins, ≥12 lymph nodes retrieved, no mortality within 90 days of surgery, no readmission within 30 days of surgery, and length of stay < 75th percentile. Patients were classified into 4 subgroups: (1) mTO, (2) TO without chemotherapy, (3) non-TO with chemotherapy, and (4) non-TO without chemotherapy. The Chi-square test was used to analyze categorical variables. The Kaplan-Meier method and log-rank test were used to compare overall survival (OS) between subgroups. Univariate and multivariable Cox proportional regression models were used, adjusting for clinical and demographic variables.

Results: Of the 225, 842 patients identified, 55.1% achieved TO while only 34.4% achieved mTO. The 5-yr OS for the entire TO and non-TO cohorts was 67% and 46%, respectively (P<0.0001). The highest 5-yr OS rate was observed in the mTO subgroup (73%) while the lowest rate was seen in the non-TO without chemotherapy subgroup (23%) (P<0.0001). Multivariable analysis demonstrated that mTO was an independent predictor of outcome; compared to mTO, the HR for non-TO with chemo was 1.35 (95% CI: 1.3-1.4), TO without chemo was 1.86 (95% CI: 1.8-1.9), and non-TO without chemo was 3.71 (95% CI: 3.6-3.8).

Conclusions: Patients with resected stage III colon cancer who achieved a textbook outcome and receipt of adjuvant chemotherapy (mTO) had superior outcomes compared to those who did not receive either a textbook outcome or chemotherapy following resection.