Reviewed: Panahi Y, Saadat A, Sahebkar A, et al. Effect of ginger on acute and delayed chemotherapy-induced nausea and vomiting: a pilot, randomized, open-label clinical trial. Integr Cancer Ther. February 7, 2012; [epub ahead of print]. doi:10.1177/1534735411433201.

For those suffering from cancer, the adverse side effects of nausea and vomiting from chemotherapy drugs can be an additional and disruptive burden. This chemotherapy-induced nausea and vomiting (CINV) generally occurs either during the initial 24 hours from chemotherapy (acute), 24 hours after chemotherapy (delayed), or as a result of association with chemotherapy in cancer patients (anticipatory). Antagonists of 5-hydroxytryptamine 3 (5-HT3) receptors are commonly used antiemetic drugs but do not help all patients; additionally, these drugs have limited efficacy for treating delayed and anticipatory CINV, necessitating alternative treatment options.

Ginger (Zingiber officinale, Zingiberaceae) root has been used traditionally as a spice and for gastrointestinal problems in many parts of the world.¹ Although previous studies report several mechanisms for the antiemetic activity of ginger root, including antagonism of 5-HT3 receptors,² clinical trials of its use are not entirely in agreement. This randomized, open-label, clinical trial investigated the use of ginger root along with standard antiemetic drugs in treating acute and delayed CINV in advanced breast cancer patients in initial chemotherapy.

This trial took place at the Oncology Unit of Baqiyatallah Hospital, Tehran, Iran. Included patients were undergoing initial chemotherapy (mostly a combination of the moderately emesis-causing chemotherapy drugs docetaxel, epirubicin, and cyclophosphamide) with a diagnosis of advanced breast cancer. The included patients were not pregnant or lactating, and none were undergoing radiation treatments. Patients enrolled in another trial, who had a bone marrow or stem cell transplantation, or who had other serious illness or suffered from motion sickness were excluded. Enrolled patients were randomly assigned to either a ginger group taking 1.5 g/day of ginger in 3 doses every 8 hours along with the standard antiemetic drugs granisetron (a 5-HT3 antagonist) and dexamethasone, or a control group taking just the pharmaceuticals.

The Iran Herb Medical Society prepared and validated the ginger, but the authors give no description as to how preparation and validation were accomplished. The ginger root (dried and powdered) was encapsulated in 500 mg amounts and manufactured by Razak Laboratories Corporation, Tehran, Iran. The first dose of ginger or placebo was given 30 minutes after the chemotherapy treatment and continued for 4 days with day 1 indicating when chemotherapy started. Patients were asked to eat easily digestible foods and avoid nausea-causing foods. No examples are given.

To assess frequency, duration, and distress of nausea, vomiting, and retching, the Rhodes Index of Nausea, Vomiting, and Retching (RINVR) was used. This scale consists of 8 questions with a score ranging from 0 (no symptoms) to 3 (highest severity). The prevalence and severity of nausea, vomiting, and retching were measured during the first 6 hours after chemotherapy treatment, during the 6-24 hours after chemotherapy, and during days 2, 3, and 4. Patients filled out the RINVR questionnaire daily and also mentioned any adverse side effects.

Of a total of 100 enrolled female patients with an average age of 51.83 ± 9.18 years, 22 were lost to follow-up or were dropped due to non-compliance. This resulted in n=37 in the ginger group and n=41 in the control group who completed the study. During the 6-24 hours after chemotherapy treatment, the prevalence of nausea was significantly reduced in the ginger group as opposed to the control group (35.3% vs. 58.5%, respectively; P=0.04). During the first 6 hours after chemotherapy, as well as on days 2, 3, and 4, no significant differences were observed with the prevalence of nausea, vomiting, and retching between groups. Also, there were no significant differences between the other average RINVR scores for nausea, vomiting, and retching between groups. Lastly, there was no difference between the number of patients experiencing symptoms of various severity as measured by the RINVR.

In summary, the ginger group experienced a significant reduction in the prevalence of nausea but no other outcomes were affected significantly by the ginger supplementation. However, the study emphasized that the non-statistically significant reductions in the prevalence of nausea in the ginger group in the initial 6 hours after chemotherapy (17%), as well as on day 2 (10%) may still be clinically relevant. Weaknesses of the study include an underpowered sample size, no use of treatment blinding, and the fact that all patients had a lower-than-expected severity and prevalence of CINV. Also, the study design of using ginger in conjunction with established antiemetic medication may have induced a “floor effect” and suppressed between-group differences. Future clinical trials with ginger supplementation on its own are needed with stronger designs. Despite these problems, this study suggests that ginger remains a robust candidate for the treatment of CINV in cancer patients.

—Amy C. Keller, PhD

References

1. Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Austin, TX: American Botanical Council; Newton, MA: Integrative Medicine Communications; 2000.
2. Huang QR, Iwamoto M, Aoki S, et al. Anti-5-hydroxytryptamine 3 effect of galanolactone, diterpenoid isolated from ginger. Chem Pharm Bull (Tokyo). February 1991;39(2):397-399.