Association between serotonin transport polymorphisms and postdischarge nausea and vomiting in women following breast cancer surgery

Abstract

Purpose/objectives: To examine the association of the serotonin transport gene and postdischarge nausea and vomiting (PDNV) in women following breast cancer surgery.

Design: A cross-sectional study.

Setting: A comprehensive cancer center in Pittsburgh, PA.

Sample: 80 post-menopausal women treated surgically for early-stage breast cancer.

Methods: Data were collected using standardized instruments after surgery but before the initiation of chemotherapy. Blood or saliva were used for DNA extraction and analyzed following standardized protocols. Data were analyzed using descriptive statistics and logistic regression.

Main research variables: Serotonin transport gene (SLC6A4), nausea, vomiting, pain, and anxiety.

Findings: Women who inherited the LA/LA genotypes were at greater risk for nausea and vomiting when compared to women who carried any other combination of genotypes. Twenty-one percent of women reported nausea and vomiting an average of one month following surgery and prior to initiation of adjuvant therapy. Those women who experienced PDNV reported significantly higher anxiety and pain scores.

Conclusions: Findings of this study suggest that variability in the genotypes of the serotonin transport gene may help to explain the variability in PDNV in women following breast cancer surgery and why 20%-30% of patients do not respond to antiemetic medications.

Implications for nursing: Nurses need to be aware that women who do not experience postoperative nausea and vomiting following surgery for breast cancer continue to be at risk for PDNV long after they have been discharged from the hospital, and this frequently is accompanied by pain and anxiety.

Keywords: breast cancer; genetics; nausea/vomiting.