Pancreatic cancer represents a serious public health problem worldwide. Due to its high mortality, efforts on identifying risk factors are very important since only a few risk-related factors have been well established. The present study aimed to address this knowledge gap by estimating the risk of pancreatic cancer associated with opium use. We performed a thorough literature search of PubMed, Web of Science and Scopus, which yielded 3 case-control and 1 cohort study which were included in the analysis. A meta-analysis was conducted using the DerSimonian and Laird inverse-variance approach as the random effects method. The pooled risk ratio for pancreatic cancer in opium users was significantly increased (RR=1.98, 95 % CI 1.33–2.96, p = 0.0008) compared to never users. Subgroup analyses identified a significantly increased risk for pancreatic cancer in men (RR=1.74, 95 % CI 1.22–2.47, p = 0.002), in persons who consumed both raw teriak and refined shireh opium (RR=4.21, 95 % 1.27–13.93, p = 0.02) and in persons who smoked opium (RR=4.21, 95 % 1.27–13.93, p = 0.02). The findings of this study will help in efforts aimed at prevention of pancreatic cancer. Still, further epidemiological research is necessary.
- • Pancreatic cancer represents a serious public health problem worldwide.
- • Pancreatic cancer risk is significantly increased in opium users.
- • Raw teriak and refined shireh opium users and men are especially at risk.
- • Findings of this study will help pancreatic cancer prevention efforts.
Pancreatic cancer is the 7th most common cause of cancer death in the world: in 2020, pancreatic cancer caused almost 470,000 deaths in both sexes (i.e. about 4.7 % of all cancer deaths globally) . In 2020, almost 500,000 patients were diagnosed with pancreatic cancer (i.e. about 2.6 % of all cancer cases globally) . Based on GLOBOCAN 2020 estimates, pancreatic cancer is ranking as the 3rd most frequent cause of cancer death in both sexes in 11 countries (the United States of America and 10 European countries) . In the last decades, the highest incidence and mortality rates of pancreatic cancer were reported in the developed countries; in 2020 in the world, the highest rates were registered in Hungary .
To date, only a few risk-related factors for pancreatic cancer have been well established, including smoking, obesity, alcohol use, genetics, diabetes, diet, inactivity, infections . Although some studies have shown an association between pancreatic cancer and opium use, the findings were not consistent . Opium is a minimally processed derivate of the opium poppy plant that is highly addictive . The main types of opium products are raw opium also known as teriak, refined opium also known as shireh and opium dross also known as sukhteh. The two main routes of consumption include smoking and ingestion (chewing, drinking, swallowing). A recent meta-analysis of cancer risk and consumption of opium found a significantly increased risk of pancreatic cancer in ever users of opium, but the authors noted that there were insufficient data to assess the risk for different types of opium used or routes of use . Cohort and case-control studies have shown conflicting results regarding this association, particularly when looking at different types of opium used, different intensity of consumption, different routes of consumption .
The latest monograph of the International Agency for Research on Cancer which evaluated the carcinogenicity of opium, classified opium as carcinogenic to humans (Group 1 carcinogen) and identified positive association between opium use and cancer of the pancreas, but the evidence was limited . However, the association between consumption of opium and pancreatic cancer has not yet been fully elucidated.
In order to address the identified knowledge gap, the aim of this study was to assess the risk for pancreatic cancer associated with opium use by performing a meta-analysis.