The impact of COVID-19 on colorectal cancer in regional Northern Australia and changes to treatment related to distance to care: A retrospective cohort study

The COVID-19 pandemic has created challenges in the diagnosis and management of colorectal cancer (CRC). It was proposed in regional Northern Australia that the distance to services could further impact cancer outcomes, leading to delayed diagnosis. We compared the outcomes of patients prior and during the pandemic; with a focus on whether patients were presenting in the emergency setting with more advanced disease. The distance to treatment was also analysed to see if there was any impact to the management of patients with colorectal cancer. A retrospective analysis of 444 patients that underwent treatment for colorectal cancer over 2 time periods were examined. Time period 1 (prior to COVID-19); March 2017-July 2019 and time period 2 (during COVID-19); March 2020-July 2022. Only patients with colorectal adenocarcinoma were included if they were primarily treated at a hospital in northern Australia; those with benign pathologies or recurrent disease were also excluded. Data was collected in terms of treatment and outcomes and compared between the two groups. A separate analysis of whether locality affected outcomes and referral times was also performed. In the time period prior to COVID-19 174 patients’ required invasive management, while in the second time period during COVID-19 there were 188 patients managed surgically or endoscopically. Of the patients managed prior to COVID-19 17/174 (9.8%) patients required emergency interventions, during COVID-19 this number increased to 37/188 (19.7%). This difference was deemed to be statistically significant (P =0.008). No substantial difference in cancer staging at presentation was found between the two groups. There was an increase in complication rate found during COVID-19 34.6% vs 25.5% prior to COVID-19 (P =0.046). During COVID-19 the median time between General Practitioner (primary care physician) referral and colonoscopy was actually lower than prior to covid 26.5 vs 36 days (P=0.047). When comparing local to distant patients we found locally based patients had lower rates of neoadjuvant treatment 18.9% vs 30.4% (P=0.018) and higher rates of open surgery 39.1% vs 26.5%, P =0.012. An increase in time between colonoscopy and outpatient department review (OPD) was seen in patients not from the local area 13 vs 18 days (P =0.006). We found during the COVID-19 pandemic a greater proportion of patients were presenting with colorectal cancer that required emergency intervention. This may be due to decreased presentations to general practitioners due to lockdown causing potential delays in diagnosis. We did not see more advanced disease in these patients presenting emergently, between the two groups. Further assessment of local patients’ vs patients from distant sites, showed difference in how patients were managed but similar outcomes. Our large catchment area with distance to treatment in Northern Australia may further impact the management of colorectal cancer in the future.