Recent data suggest that the mu opioid receptor (MOR), which is commonly the target of constipation treatments, could also be a target for anticancer therapy.
US researchers explored this hypothesis by studying survival data for 229 advanced cancer patients involved in two placebo-controlled trials of the MOR antagonist methylnaltrexone (MNTX) for opioid-induced constipation.
They found that patients who received MNTX survived significantly longer on average, at 76 days, compared with 56 days among those who received placebo. In patients who responded to MNTX with laxation, average survival was even longer at 118 days, while survival in non-responders was similar to placebo at 55 days.
Reporting in the Annals of Oncology (online, 29 August 2016)
, the researchers say the findings support a role for the MOR in cancer progression and prospective studies of MNTX are warranted to confirm the clinical relevance of their results.
 Janku F, Johnson LK, Karp DD et al. Treatment with methylnaltrexone is associated with increased survival in patients with advanced cancer. Annals of Oncology 2016. doi: 10.1093/annonc/mdw317