Opium use as an independent risk factor for pancreatic cancer: A case-control study

1

Introduction

One of the most lethal cancers worldwide is pancreatic cancer. PC is the seventh leading cause of death of cancers in both genders and according to the GLOBOCAN, the pancreatic cancer accounted for 4% of deaths [ 1 ]. In 2018, PC was fourteenth common cancer in Iran; and cause of 3.8 % of cancer deaths [ 2 ].

Research has shown that pancreatic cancer has several modifiable risk factors including high body mass index (BMI) and diabetes [ 3 ]. However, cigarette smoking is the strongest known environmental risk factor for PC [ 4 ], but the relationship between smoking and different cancers in Iran has often been much less strong than what is seen in Western countries [ 4567 ]. Accordingly, several meta-analyses have shown the risk of PC due to cigarette smoking, to be depended on the duration and frequency of smoking, the odds ratios (OR) range from 1.5 to 2.0 [ 5 ]. The results of pooled analysis of case-control studies support a moderate increased risk of pancreatic cancer with heavy daily alcohol consumption ; however, there was no evidence for a role of light or moderate alcohol drinking in pancreatic carcinogenesis, but the increased risk was seen only for heavy drinking [ 7 ].

Recently the long-term effects of opium consumption, especially its carcinogenic effects have been assessed [ 8 ]. Previous studies have addressed the effects of opium use on the incidence of cancers like esophagus [ 910111213 ], stomach [ 14 , 15 ], larynx [ 16 ], lung [ 17 , 18 ] colorectal [ 19 , 20 ], bladder [ 21222324 ], head and neck [ 25 , 26 ] Brain, and liver [ 27 ] cancers. However, there are few studies on the effect of opium use on the incidence of PC [ 2 , 28 ].

Opium is a substance commonly used for recreational and medical purposes in some people in different regions throughout the world. Besides, Based on the national survey which was done among Iranian workers, opium was the most popular substance used 2.7 %, but the simultaneous biochemical assessment conforms this predominance with 14.4 % positive results [ 29 ].

In Kerman, one of the southern cities of Iran, due to geographical conditions, the rate of opium usage is high, and in several studies, it is estimated to be between 11 and 15 % [ 303132 ]. This substance is mostly used orally or smoked [ 8 ]. In a recent study in Kerman, on hospitalized patients and their healthy companions, the rate of self-reported opium use was 36.5 % in patients and 19.3 % in healthy companions [ 33 ].

Recent studies in north of Iran, known as region with high opioid use, have found a relationship between pancreatic cancer and opium use [ 2 , 28 ].

According a study of International Agency for Research on Cancer on the carcinogenicity of opium, the positive association has been established between larynx, lung, and bladder; however, the evidence was limited for other cancers such as pancreatic cancer [ 34 ].

Hence, this case-control study aimed to assess the relation between opium usage and the risk of PC in Iran. According to the limitation of the current evidence in this issue, this study could be a valuable study to show this gap. It also explores the impact of cigarette smoking and alcohol use on the risk of PC.