The Iranian Study of Opium and Cancer (IROPICAN): Rationale, design, and initial findings

Maryam Hadji, Hamideh Rashidian, Maryam Marzban, Mahin Gholipour, Ahmad Naghibzadeh-Tahami, Elham Mohebbi, Elmira Ebrahimi, Bayan Hosseini, Ali Akbar Haghdoost, Abbas Rezaianzadeh, Afarin Rahimi-Movaghar, Abdolvahab Moradi, Monireh Sadat Seyyedsalehi, Reza Shirkoohi, Hossein Poustchi, Sareh Eghtesad, Farid Najafi, Roya Safari-Faramani, Reza Alizadeh-Navaei, Ali Reza Ansari MoghadamMahdieh Bakhshi, Azim Nejatizadeh, Masumeh Mahmudi, Soudabeh Shahid-Sales, Saideh Ahmadi-Simab, Omid Nabavian, Paolo Boffetta, Eero Pukkala, Elisabete Weiderpass, Farin Kamangar, Kazem Zendehdel

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Background: The International Agency for Research on Cancer (IARC) recently classified opium use as a Group 1 carcinogen. However, much remains to be studied on the relation between opium and cancer. We designed the Iranian Opium and Cancer (IROPICAN) study to further investigate the association of opium use and cancers of the head and neck, bladder, lung, and colon and rectum. In this paper, we describe the rationale, design, and some initial results of the IROPICAN Study. Methods: The IROPICAN is a multi-center case-control study conducted in 10 provinces of Iran. The cases were all histologically confirmed and the controls were selected from hospital visitors who were free of cancer, were not family members or friends of the cancer patients, and were visiting the hospital for reasons other than their own ailment. The questionnaires included detailed questions on opium use (including age at initiation, duration, frequency, typical amount, and route), and potential confounders, such as tobacco use (e.g., cigarettes, nass and water-pipe), and dietary factors. Biological samples, including blood and saliva, were also collected. Results: The validation and pilot phases showed reasonably good validity, with sensitivities of 70% and 69% for the cases and controls, respectively, in reporting opium use. The results also showed excellent reliability, with intra-class correlation coefficients of 0.96 for ever opium use and 0.88 (95% CI: 0.80, 0.92) for regular opium use. In the main phase, we recruited 3299 cancer cases (99% response rate) and 3477 hospital visitor controls (89% response rate). The proportion of ever-use of opium was 40% among cases and 18% among controls. Conclusion: The IROPICAN study will serve as a major resource in studies addressing the effect of opium on risk of cancers of the head and neck, bladder, lung, and colon and rectum.

Original languageEnglish
Pages (from-to)167-176
Number of pages10
Issue number3
Publication statusPublished - 2021
Publication typeA1 Journal article-refereed


  • Bladder cancer
  • Colorectal cancer
  • Head and neck cancer
  • Lung cancer
  • Opium
  • Protocol

Publication forum classification

  • Publication forum level 1

ASJC Scopus subject areas

  • Medicine(all)


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