Geographic variation in diagnostic and treatment interval, cancer stage and mortality among colorectal patients - An international comparison between Denmark and Scotland using data-linked cohorts

High polygenic risk score is a risk factor associated with colorectal cancer based on data from the UK Biobank

Colorectal cancer (CRC) is a common cancer among both men and women and is one of the leading causes of cancer death worldwide. It is important to identify risk factors that may be used to help reduce morbidity and mortality of the disease. We used a case-control study design to explore the association between CRC, polygenic risk scores (PRS), and other factors. We extracted data about 2,585 CRC cases and 9,362 controls from the UK Biobank, calculated the PRS for these cases and controls based on 140 single nucleotide polymorphisms, and performed logistic regression analyses for the 11,947 cases and controls, for an older group (ages 50+), and for a younger group (younger than 50). Five significant risk factors were identified when all 11,947 cases and controls were considered. These factors were, in descending order of the values of the adjusted odds ratios (aOR), high PRS (aOR: 2.70, CI: 2.27-3.19), male sex (aOR: 1.52, CI: 1.39-1.66), unemployment (aOR: 1.47, CI: 1.17-1.85), family history of CRC (aOR: 1.44, CI: 1.28-1.62), and age (aOR: 1.01, CI: 1.01-1.02). These five risk factors also remained significant in the older group. For the younger group, only high PRS (aOR: 2.87, CI: 1.65-5.00) and family history of CRC (aOR: 1.73, CI: 1.12-2.67) were significant risk factors. These findings indicate that genetic risk for the disease is a significant risk factor for CRC even after adjusting for family history. Additional studies are needed to examine this association using larger samples and different population groups.

The impact of rurality on patient experience and diagnostic pathway intervals in Scotland's cancer patients: Further results from a national cancer diagnosis audit

BACKGROUND

In Scotland 17 % of the population reside rurally and previous research has demonstrated worse cancer outcomes in this group. The underlying reason for this is unclear. This study aims to determine whether patient presenting factors, GP consultation factors or the diagnostic pathways differ between urban and rural patients within Scotland.

METHODS

This study combined two Scottish National Cancer Diagnosis Audits. Participating GPs collected data on the diagnostic pathway from primary to secondary care for cancer patients diagnosed during the audit period. Using the Scottish Government Urban Rural Classification, patients were designated as rural or urban dwellers and compared in descriptive analyses. Key cancer intervals (primary, diagnostic, secondary and treatment interval) were compared between urban and rural dwellers with an additional adjusted analysis for the main cancer sites.

RESULTS

A total of 4309 cancer diagnoses were included in the study; 22 % were in patients from rural locations. Rural patients had significantly more consultations and investigations prior to referral than their urban counterparts. There was no difference in prolonged cancer pathways between the two groups except in lung cancer patients where rural patients had a significantly increased odds of a diagnostic interval of >90 days.

CONCLUSION

Our findings suggest differences in the interaction between patients and GPs prior to referral in urban and rural settings. However, this does not appear to lead to prolonged patient pathways, except in lung cancer. Further research is needed to determine whether this delay is clinically significant and contributing to poorer outcomes in Scottish rural dwellers with lung cancer.

The association between sociodemographic factors and time to diagnosis for colorectal cancer in northern Sweden

OBJECTIVES

This study examined whether sociodemographic factors, including distance to hospital, were associated with differences in the diagnostic interval and the treatment interval for colorectal cancer in northern Sweden.

METHODS

Data were retrieved from the Swedish cancer register on patients (n = 446) diagnosed in three northern regions during 2017-2018, then linked to data from Statistics Sweden and medical records. Also, Google maps was used to map the distance between patients' place of residence and nearest hospital. The different time intervals were analysed using Mann-Whitney U-test and Cox regression.

RESULTS

Differences in time to diagnosis were found between groups for income and distance to hospital, favouring those with higher income and shorter distance. The unadjusted regression analysis showed higher income to be associated with more rapid diagnosis (HR 1.004, CI 1.001-1.007). This association remained in the fully adjusted model for income (HR 1.004, CI 1.000-1.008), but not for distance. No differences between sociodemographic groups were found in the treatment interval.

CONCLUSION

Higher income and shorter distance to hospital were in the unadjusted models associated with shorter time to diagnosis for patients with CRC in northern Sweden. The association remained for income when adjusting for other variables even though the difference was small.