Introduction of a colorectal cancer screening programme: results from a single-centre study

Improved stage and survival for patients in the Aotearoa New Zealand colorectal cancer screening program 2012-2019

BACKGROUND

Colorectal cancer (CRC) screening was introduced in Aotearoa New Zealand at Waitematā District Health Board (WDHB) in late 2011. This study reviewed patterns of disease, treatment received, and survival of patients with national bowel screening program (NBSP)-detected CRC versus non-NBSP patients at WDHB 2012-2019.

METHODS

Data collected retrospectively for all patients with adenocarcinoma of the colon or rectum at WDHB 2012-2019. Patient records were manually reviewed. Chi-square, Fisher's exact test and the Mann Whitney U-test used as appropriate. Kaplan-Meier and Cox proportional hazards regression modelling for survival analysis.

RESULTS

1667 patients included (360 NBSP and 1307 non-NBSP). 863 (51.8%) were male. Median age at diagnosis 73 years (range 21-100); NBSP patients were younger (median 68 vs. 76 years, P < 0.001). NBSP patients had significantly lower T, N, M and overall TNM stage than non-BSP patients. Median survival estimate on Kaplan-Meier analysis was 94 months for all patients. Statistically significant (P < 0.05) predictors of mortality on multi-variate regression analysis included increasing overall TNM stage compared with stage I (stage II HR 1.63 (95% CI 1.14-2.34), stage III HR 2.86 (95% CI 2.03-4.03), stage IV HR 7.73 (95% CI 5.59-10.68)), diagnosis within NBSP (HR 0.51 (95% CI 0.37-0.71)), increasing age in years (HR 1.03 (95% CI 1.02-1.03)), urgent/emergency surgery (HR 1.66 (95% CI 1.36-2.01)) and formal resection of primary tumour (HR 0.31 (95% CI 0.25-0.38)).

CONCLUSION

Patients diagnosed within the Aotearoa New Zealand NBSP were found to be younger and have earlier stage CRC. Diagnosis within the NBSP is an independent predictor of survival for patients with CRC.

IMPACT OF SCREENING ON SHORT-TERM MORTALITY AND MORBIDITY FOLLOWING TREATMENT FOR COLORECTAL CANCER

BACKGROUND AND AIMS

The aim of this study was to describe short-term changes in morbidity and mortality associated with the implementation of screening for colorectal cancer in Denmark.

MATERIALS AND METHODS

Prospective cohort study with inclusion of all patients aged 50-75 years treated for colorectal cancer between 1 March 2014 and 31 December 2015 in Denmark. Adjusted hazard ratios were calculated for 30 and 90 days mortality using Cox Regression. We made two adjusted models-a "basic" adjusted for screening status, sex, age, smoking, alcohol consumption, and cancer type and an "advanced" that also included body mass index and American society of Anesthesiologists score in analyses. Relative risks were calculated for postoperative surgical and medical complications.

RESULTS

In total, 5348 patients were included. In the "basic model," adjusted risk of 30 and 90 days total mortality was reduced in the screen-detected group (p < 0.01, HR = 0.43, CI = 0.24-0.76) and (p < 0.01, HR = 0.45, CI = 0.30-0.69). In the "advanced model," only 90 days total mortality was significantly reduced in the screen-detected group (p = 0.01, HR 0.59, CI = 0.39-0.90). No significant changes were found with regard to surgical and medical complications, respectively, (p = 0.05 (CI = 0.76-1.00) and p = 0.47(CI = 0.74-1.15)).

CONCLUSION

This nationwide study showed that screening for colorectal cancer was associated with a lower 90 days total mortality although no significant improvements were seen with regard to morbidity.