The complication sum score: A Delphi-based approach to summarize treatment related complications for esophageal cancer

<h2>Abstract</h2><h3>Background and purpose</h3> Prevention of treatment-related complications remains a major challenge in esophageal cancer (EC) patients undergoing neoadjuvant chemoradiotherapy (nCRT) ± surgery. A single measure, reflecting the total complication burden, may provide a clear overall picture of patient burden and enables a direct comparison of alternative treatment strategies. We developed a Complication Sum Score (CSS) to quantify symptomatic complications. <h3>Materials and methods</h3> A Delphi consensus procedure was used to develop the CCS using the expertise of health professionals to assess the impact of a spectrum of complications. The impact of each complication was scored on a 0–100 scale. Consensus for these scores was defined as an interquartile range ≤ 20. The association between the CSS and hospital/ICU stay, overall survival (OS) at 1 year and quality of life (QoL) was assessed in a multicenter dataset of patients with EC, using multivariable (logistic) regression analysis, correcting for possible confounders. <h3>Results</h3> Forty-five experts completed the two-round Delphi procedure. Consensus was reached for all (36) complications. In 1225 patients, that underwent nCRT and esophagectomy, a higher CSS was significantly associated with a longer hospital (coefficient = 0.43[0.38–0.48], p < 0.01) and ICU stay (coefficient = 0.23[0.19–0.26], p < 0.01), and a worse OS (odds ratio = 1.005[1.004–1.006], p < 0.01). Among the patients that completed a QoL questionnaire after surgery (n = 98) an increased CSS was associated with worse QoL (coefficient = -0.24[-0.01–0.49], p = 0.06). <h3>Conclusion</h3> The CSS offers a comprehensive tool to quantify treatment-related complications in a single score in EC patients that receive nCRT followed by surgical resection.