Increased cancer incidence and mortality among people with opioid use-related disorders: A nation-wide cohort study.

BACKGROUND AND AIMS: Studies on cancer incidence and mortality among people with opioid use-related disorders are lacking. We aimed to measure cancer-specific incidence, mortality and survival among people diagnosed with opioid use-related disorders in Norway during 2010-18.

DESIGN AND

SETTING

This was a cohort study conducted in Norway during 2010-18.

PARTICIPANTS

Individuals (n = 20 710) diagnosed with opioid use-related disorders.

MEASUREMENTS: We conducted a cohort study utilizing a data-linkage of national health and population registers. Information on opioid use-related disorders was extracted from specialized healthcare, malignancies from the Cancer Registry of Norway and deaths from Cause of Death Registry. Cancer incidence and mortality were compared with the general population by calculating sex-specific age-standardized incidence (SIR) and mortality (SMR) ratios. One-year survival rates were computed.

FINDINGS: Compared with the general population, people with opioid use-related disorders were at an increased risk of developing cancer overall [SIR = 1.2, 95% confidence interval (CI) = 1.1-1.3] with a higher than twofold cancer mortality rate (SMR = 2.3, 95% CI = 2.0-2.7). Excess risk was observed for liver (12.6, 95% CI = 9.1-17.0), larynx (4.7, 95% CI = 1.7-10.2), lung (3.5, 95% CI = 2.8-4.3) and pancreas cancer (2.6, 95% CI = 1.6-4.0), whereas reduced risk was found for melanoma (0.5, 95% CI = 0.3-0.9), breast (0.6, 95% CI = 0.4-0.9) and prostate cancers (0.3, 95% CI = 0.1-0.4). Site-specific SMRs were significantly elevated for liver (12.3, 95% CI = 8.5-17.2), lung (3.9, 95% CI = 3.0-5.0), pancreas (3.0, 95% CI = 1.7-4.8) and colon cancers (1.9, 95% CI = 1.1-3.1). The average 1-year survival rate after a cancer diagnosis was low in liver, pancreas and colon cancer, ranging from 10 to 15% less than that of the general population.

CONCLUSIONS

In Norway, cancer incidence and cancer-related mortality appear to be elevated among individuals with opioid use-related disorders.