The role of opioid use in the progression of cancer has caused concerns, despite little existing literature of human clinical studies.
A study led by UC Irvine and Duke University, presented at the 2017 American Academy of Pain Medicine meeting in Orlando, examined the association between opioid therapy and melanoma progression in patients diagnosed with the disease.
An association between opioid use and tumor growth progression was previously reported in research using animal models. However, limited research has focused on the relationship in humans. 

The researchers conducted a retrospective review of electronic health records between 2014 and 2015. They identified a total of 45 patients diagnosed with melanoma and determined whether or not they were treated with opioids after diagnosis, and then examined the difference in melanoma progression using the Fisher’s exact test.
Out of the 22 patients examined with melanoma progression, the researchers found no difference in time to progression between patients taking or not taking opioids before their diagnosis. Overall, the researchers did not find evidence of a statistically significant association between opioid use and cancer progression in patients with melanoma.
Kandil A, Gulur P, Ong E. Abstract 196. Role of opioid therapy in cancer progression. Presented at: American Academy of Pain Medicine 33rd Annual Meeting. Mar. 16-19, 2017. Orlando, Florida.
Afsharimani B, Cabot P, Parat M-O. Morphine and tumor growth and metastasis. Cancer Metastasis Rev 2011;30(2):225–38. Funding: None
Borner C, Warnick B, Smida M, et al. Mechanisms of opioid-mediated inhibition of human T cell receptor signaling. J Immunol [Internet] 2009;183(2):882–9. Available from:
 McCarthy L, Wetzel M, Sliker JK, Eisenstein TK, Rogers TJ. Opioids, opioid receptors, and the immune response. Drug Alcohol Depend 2001;62(2):111–23.