Impact of travel time and rurality on presentation and outcomes of symptomatic colorectal cancer: a cross-sectional cohort study in primary care

Abstract

Background: Several studies have reported a survival disadvantage for rural dwellers who develop colorectal cancer, but the underlying mechanisms remain obscure. Delayed presentation to GPs may be a contributory factor, but evidence is lacking.

Aim: To examine the association between rurality and travel time on diagnosis and survival of colorectal cancer in a cohort from northeast Scotland.

Design and setting: The authors used a database linking GP records to routine data for patients diagnosed between 1997 and 1998, and followed up to 2011.

Method: Primary outcomes were alarm symptoms, emergency admissions, stage, and survival. Travel time in minutes from patients to GP was estimated. Logistic and Cox regression were used to model outcomes. Interaction terms were used to determine if travelling time impacted differently on urban versus rural patients.

Results: Rural patients and patients travelling farther to the GP had better 3-year survival. When the travel outcome associations were explored using interaction terms, the associations differed between rural and urban areas. Longer travel in urban areas significantly reduced the odds of emergency admissions (odds ratio [OR] 0.62, P<0.05), and increased survival (hazard ratio 0.75, P<0.05). Longer travel also increased the odds of presenting with alarm symptoms in urban areas; this was nearly significant (OR 1.34, P = 0.06). Presence of alarm symptoms reduced the likelihood of emergency admissions (OR 0.36, P<0.01).

Conclusion: Living in a rural area, and travelling farther to a GP in urban areas, may reduce the likelihood of emergency admissions and poor survival. This may be related to how patients present with alarm symptoms.

Keywords: access; cancer symptoms; early diagnosis; geography; primary care; rurality.

Figure 1.

Differences in association between rural and urban areas, with and without interaction terms. 1a–4a show differences in association between rural and urban areas (from Table 2, models 1d–4d). The lines show modelled association between travel time and alarm symptoms (1a), emergency admission (2a), Dukes’ stage (3a), and 3-year survival (4a). 1b–4b show the difference in the rural versus urban slope, along with 95% CIs. These differences are statistically significant where the CIs do not cross the zero line.