Temporal development in survival, and gender and regional differences in the Swedish population of patients with synchronous and metachronous metastatic colorectal cancer

Abstract

Background

Survival in patients with metastatic colorectal cancer (mCRC) has markedly improved in patients included in clinical trials. In population-based materials, improvements were seen until about a decade ago, but it is unclear if survival has continued to improve. It is also unclear if regional or gender differences exist.

Material and methods

All patients with mCRC (N = 19,566) in Sweden between 2007 and 2016 were identified from the national quality register, SCRCR, with almost complete coverage. Overall survival (OS) from diagnosis of metastatic disease was calculated in two calendar periods, 2007–2011 and 2012–2016. Differences between groups were compared using Cox regression.

Results

Median age was 72 years, 55% were males, synchronous presentation was seen in 13,630 patients and metachronous in 5936. In synchronous disease, the primary tumour was removed more often during the first than the second period (51% vs 41%, p < 0.001). Median OS (mOS) was 14.0 months. It was longer in those with metachronous than synchronous disease (17.6 vs 13.1 months, p < 0.001) and in males (15.0 vs 12.8 months, p < 0.001), and markedly influenced by age and primary location. It was longer in patients diagnosed during the second period than during the first (14.9 vs 13.1 months, HR 0.89 (95% CI 0.86–0.92), p < 0.001). This difference was seen in all subgroups according to sex, age, presentation, and sidedness. mOS was about one month shorter in 1/6 healthcare regions, most pronounced during the first period. Differences in median of up to 5 months were seen between the region with the shortest and longest mOS.

Conclusions

Overall survival in Swedish patients with mCRC has improved during the past decade but is still substantially worse than reported from clinical trials/hospital-based series, reflecting the selection of patients to trials. Regional differences were seen, but they decreased with time. Women did not have a poorer prognosis in multivariable analyses.

Keywords:

• Metastatic colorectal cancer
• population
• survival
• regional differences
• gender differences

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Additional information

Funding

This work was supported by the Swedish Cancer Society [grant number 190382].