Exploring the multifactorial nature of postoperative nausea and vomiting in women following surgery for breast cancer.

Background: Postoperative nausea and vomiting (PONV) are two of the most frequent and distressing complications following surgical procedures, with as many as 80% of patients considered to be at risk. Despite recognition of well-established risk factors and the subsequent use of clinical guidelines, 20-30% of women do not respond to antiemetic protocols, indicating that there may be a genetic risk.

Objective: The purpose of this pilot study was to describe the incidence and explore the risk factors associated with PONV after surgery in women diagnosed with early stage breast cancer.

Methods: A prospective cohort design was employed to measure PONV in women recruited prior to surgery. DNA was extracted from saliva samples collected prior to discharge. Polymorphisms for seven candidate genes with a known role in one of the neural pathways associated with PONV were included in this study; serotonin receptor (HTR3A), serotonin transport (SLC6A4), tryptophan (TPH), dopamine receptors (DRD2/ANKK and DRD3), catechol-O-methyltransferase (COMT) and histamine (H1).

Results: Twenty-nine (29.8%) women experienced nausea and 10 (11%) experienced nausea and vomiting while in the PACU despite administration of multiple antiemetic medications. Women who experienced PONV had higher levels of pain and received more opioids than those women who did not experienced PONV. Odds ratios demonstrated that alleles for the COMT, DRD3, and TPH genes were associated with decreased PONV.

Conclusion: The understanding of the multifactorial nature of PONV and the recognition of genetic risk will ultimately lead to the development of personalized interventions to manage these frequent and often debilitating symptoms.