The multifaceted impact of the COVID-19 pandemic on colorectal cancer care: a systematic review of management disruptions, stage migration, and survival outcomes.

BACKGROUND: The COVID-19 pandemic caused a catastrophic disruption to global healthcare systems. For colorectal cancer (CRC), the world's third most prevalent cancer, the suspension of screening programs and reallocation of resources threatened to severely impact timely diagnosis and treatment, with pre-existing models predicting significant excess mortality from even short delays. OBJECTIVE: This systematic review aimed to assess the impact of the COVID-19 pandemic on the management strategies, treatment outcomes, and survival rates of patients with colorectal cancer. METHODS: A systematic review was conducted following PRISMA guidelines. A comprehensive search of PubMed was performed for studies published from 2020 onwards. Eligible studies included those focusing on adult CRC patients and reporting on changes in care pathways or outcomes due to the pandemic. Data on diagnostic delays, treatment modifications, stage at presentation, and survival were extracted and synthesized narratively. RESULTS: The synthesis of results from the included studies revealed a cascade of negative consequences. There was a severe global reduction in CRC screening, with participation declining by 30-80% and colonoscopy volumes falling by up to 92%, leading to a pool of "missing" diagnoses. This resulted in a significant stage shift, with a higher proportion of patients presenting with advanced stage (e.g., Stage IV) and locally advanced tumors. Treatment protocols were modified, including reduced elective surgical volumes and increased use of neoadjuvant therapy. Consequently, patients diagnosed during the pandemic faced a significantly higher mortality risk, a trend exacerbated by COVID-19 co-infection, which was associated with dramatically worse survival. The pandemic also exacerbated health disparities and imposed a profound psychosocial burden on patients. CONCLUSION: The COVID-19 pandemic had a detrimental impact on every facet of colorectal cancer care, from screening and diagnosis to treatment and outcomes, leading to more advanced disease at presentation and worsening survival. These findings underscore the critical need to develop resilient cancer care systems that can maintain essential services during future public health crises. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42025638100.