Does Waiting Time from Diagnosis to Treatment Affect Outcome in Locally Advanced Rectal Cancer? Real World Data Analysis

Abstract

Introduction: Rectal cancer is a common and lethal disease, with approximately 44,180 new cases of diagnosed annually in the United States and a five-year survival of 67% [1, 2]. The interval from diagnosis to chemoradiation treatment, or waiting time (WT), is considered to be an important quality indicator for cancer care and has been demonstrated to be associated with oncologic outcomes in various cancers [3, 4]. The current recommendation for pre-treatment staging evaluation includes rigid proctoscopy, PET CT, transrectal ultrasound (TRUS) and often rectal MRI. These diagnostic procedures may significantly postpone the start of treatment. We aim to examine the effect of WT on overall survival (OS) and disease free survival (DFS) of rectal cancer patients. Methods: Retrospective analysis was performed in a detailed database of patients with resectable primary rectal cancer who underwent chemoradiation between January 2000 and January 2019. Univariate and multivariate cox proportional hazard regressions were conducted in order to evaluate the effect of WT on oncological outcomes. Results: 387 patients were enrolled in our database; of them 297 patients were eligible by the inclusion criteria. Median WT was 6.3 weeks (IQR 4.3-8.7). Multivariate analysis showed adjusted Hazard Ratio (HR) for OS increases by 1.07 for each additional week of therapeutic delay in all age groups (p=0.025). Furthermore, focusing on the majority of patients in the age group 45 - 70 years, adjusted HR for OS increases by 1.12 for each additional week of therapeutic delay (p=0.011). Adjusted HR for DFS increases by 1.06 for each additional week of therapeutic delay in all age groups (p=0.045) and an increment by 1.09 for each additional week of therapeutic delay in age group 45-70 years (p=0.02). Conclusion: Prolonged WT leads to significant poorer overall survival in patients with primary rectal cancer who underwent chemoradiation and curative surgical treatment. This marks the importance of efficient diagnostic evaluation and clinical multidisciplinary decision making in a timeframe of 6 weeks in order to not jeopardize oncological outcomes.