Low Income Has a Negative Effect on Survival Following Diagnosis of Metastatic Colorectal Cancer-A Population-Based Cohort Study.

BACKGROUND

Treatment for metastatic colorectal cancer (mCRC) has seen great advances but may not be equally available for all patients.

AIM: To evaluate the impact of socioeconomic status on cancer-specific survival after diagnosis of mCRC, with emphasis on potential temporal trends in the effect of income.

METHODS

This population-based cohort study, based on 90,620 patients diagnosed with colorectal cancer in Sweden during 2007-2021 and registered in CRCBaSe, identified 33,498 patients with mCRC through 2022. We used relative survival to estimate excess mortality rate ratios (EMRRs) with 95% confidence intervals (CIs) comparing net survival by income quartiles, adjusting for sex, age, calendar year, education, marital status and birth country.

RESULTS

One-year relative survival improved from 55% in 2007-2012 to 63% in 2017-2022. In the first years after the diagnosis of metastases there was an income gradient with the biggest contrast between high-income and low-income patients (EMRR (95% CI) at one year: 0.84 (0.81-0.88)). Year of mCRC diagnosis did not alter the effect of income on survival.

CONCLUSIONS

Despite significant improvements in cancer-specific survival for mCRC over the last decades, socioeconomic disparities, particularly based on income, continue to affect survival outcomes. The impact of income remains consistent from 2007 to 2021.