Early colorectal cancer treatment and outcomes in Scotland: real world evidence from national linked administrative data


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Elizabeth Lemmon1, Elizabeth Lemmon1, Peter Hall1, Catherine Hanna2, Katharina Diernberger1, Eva Morris3
1University of Edinburgh, 2University of Glasgow, 3University of Oxford

Abstract

Background

Colorectal cancer (CRC) is the third most common type of cancer in Scotland and the second leading cause of cancer death. Despite improvements in CRC survival over time, Scotland lags behind its UK and European counterparts. Linked administrative datasets can provide a real-world representation of current care. In this study, we aim to provide up to date, population level evidence on CRC treatment and survival outcomes in Scotland.

Method

We conducted a retrospective analysis of adults with an incident CRC registered on the Scottish Cancer Registry (ICD-10 C18-20) between January 2006 and December 2018. We linked cancer incidences to hospital inpatient records and carried out descriptive analysis on all patients (n = 44,875). Specifically, we described their demographic, diagnostic and treatment characteristics. Subsequently, we identified a curative cohort (n = 26,204) and estimated Cox-Proportional Hazards regressions to assess the factors affecting overall survival (OS) and CRC specific survival (CRCS). Since the disease trajectories and treatment pathways are quite different for patients with rectal compared to patients with colon cancer, analysis was carried out separately for these two disease sites.

Results

Overall, 32,690 (73%) and 12,184 (27%) patients had a diagnosis of colon and rectal cancer respectively. Patients with rectal cancer had a higher comorbidity score compared to those with colon cancer (1.17 versus 1.04) and were more likely to be diagnosed with stage I (21% versus 13%) or unknown disease (24% versus 15%). Patients with colon cancer were less likely to receive chemotherapy (30% versus 42%) and radiotherapy (2% versus 39%). Five year OS (CRCS) for the curative cohort was 71% (81%) and 75% (82%) for patients with colon and rectal cancer respectively. The adjusted regression models show that several factors significantly affect the risk of death from any cause or CRC specifically for both groups of patients. 

Conclusion

In a Scottish population of patients with CRC treated with curative intent, even after accounting for tumour characteristics and comorbidity, there are significant differences in survival for patients depending on their sex and geography.  

Impact statement

National linked administrative datasets have the ability to provide real-world representation of the treatments and outcomes for patients with cancer.