Detrimental impact of symptom-detected colorectal cancer

Abstract

Background: The incidence and mortality rates of colorectal cancer (CRC) have been steadily decreasing, largely attributable to screening colonoscopies that either remove precancerous lesions or identify CRC earlier. We aimed to assess the prognostic difference between colorectal cancers diagnosed by screening (SC), diagnostic (DC), or surveillance (SU) colonoscopies.

Methods: All 1809 surgically treated patients with primary CRC diagnosed through colonoscopy at our tertiary center (2004-2015) were extracted from a prospectively maintained database. Oncologic outcomes were compared, including multivariate Cox regression.

Results: Diagnostic patients presented with more advanced disease (15.0% vs. 53.2% (SC) and 55.3% (SU) AJCC I, P < 0.001), subsequently leading to impaired survival and higher recurrence rates (P < 0.001). After adjustment for age, ASA-score and gender, oncologic outcomes remained significantly worse after DC. Hazard ratios (HR) of overall mortality (OS) compared to DC were 0.36 for SC and 0.58 for SU (P < 0.001). Adjusted HRs of disease-free survival (DFS) were 0.43 and 0.32, respectively (P < 0.001). Worse outcomes in OS withstood adjustment for stage, tumor site and (neo)adjuvant treatment (SC: HR 0.46, P < 0.001; SU: HR 0.73, P = 0.036). The benefits of SC were particularly seen in colon cancer, stages I-II and female patients. With regard to DFS, outcomes were less profound and mainly true in early stage disease and surveillance patients.

Conclusions: This study demonstrates the enormous impact of asymptomatic screening in CRC. Patients with CRC diagnosed through screening or surveillance had a significantly better prognosis compared to patients who presented symptomatically. This emphasizes the importance of screening.

Keywords: Colonoscopy; Colorectal cancer; Disease recurrence; Early detection; Survival.