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Key Words

Radiation therapy, nausea, vomiting, supportive care, ondansetron (Zofran®), dexamethasone. (Definitions of many terms related to cancer can be found in the Cancer.gov Dictionary.)

Summary

Addition of the steroid drug dexamethasone to standard supportive care for patients undergoing radiation therapy to the stomach area provided significantly better complete control of vomiting, lower levels of nausea, and less use of emergency anti-nausea medications during the course of treatment. Dexamethasone is a potentially useful addition to therapy for patients in this setting.

Source

Journal of Clinical Oncology, July 20, 2006 (see the journal abstract).
(J Clin Oncol 2006 Jul 20;24:3458-64)

Background

Radiation therapy is an important part of treatment for many types of cancer. Unfortunately, it can also produce side effects that interfere with patients’ quality of life. These side effects differ depending on the part of the body receiving the radiation. Radiation therapy to the stomach, abdomen, or pelvis can often cause nausea and vomiting.

Currently, the drug ondansetron (Zofran®) is commonly used to control nausea and vomiting in patients undergoing radiation therapy. Recent clinical trials have suggested that the steroid drug dexamethasone is also effective in this regard, without producing additional side effects. The trial described below tested whether the combination of ondansetron and dexamethasone is more effective in controlling radiation-induced nausea and vomiting than ondansetron alone.

The Study

Patients scheduled to receive fractionated radiation therapy (radiation therapy given in several small, equal doses delivered over a period of several days) to the abdomen, pelvis, or both were eligible to participate in the trial. Out of 204 eligible patients, investigators randomly assigned 103 to receive ondansetron alone (standard care group) and 101 to receive both ondansetron and dexamethasone (experimental group).

In both groups, patients received an ondansetron pill twice daily during the first five radiation therapy fractions. A dexamethasone pill was given to the experimental group once a day during the first five radiation therapy fractions. The standard care group received a placebo pill in place of the dexamethasone.

Patients in both groups were given an ‘emergency kit’ consisting of extra medications, in case nausea and vomiting persisted in spite of the use of ondansetron with or without dexamethasone during the first five fractions.

Patients recorded all symptoms experienced during radiation fractions 1 to 15. The investigators evaluated control of nausea and vomiting over two periods of time:

• Whether the combination would be more effective than ondansetron alone in controlling nausea and vomiting during the first five radiation therapy fractions
• Whether the combination would be more effective than ondansetron alone at providing sustained control of nausea and vomiting during fractions 1-15

The investigators also compared side effects, use of emergency anti-nausea medications, and quality of life between groups.

Results

No statistically significant difference in complete or partial control of vomiting during fractions 1-5 was seen between the two groups, though a trend toward complete control of nausea was seen in patients receiving the combination. No difference was seen between groups in the number of patients who took emergency anti-nausea medications during fractions 1-5.

However, the addition of dexamethasone did provide significantly better complete control of vomiting, lower levels of nausea, and less use of emergency anti-nausea medications over the entire study period (fractions 1-15). No significant differences were seen in partial control of vomiting and complete control of nausea during the same time.

The addition of dexamethasone did not significantly increase the incidence of side effects compared to ondansetron alone. The most common side effects seen overall were mild constipation, headache, and upset stomach. One patient receiving dexamethasone developed a gastric ulcer. A trend toward improved overall quality of life was seen with the addition of dexamethasone.

Limitations

Physicians may be hesitant to automatically place all patients on dexamethasone starting with fractions 1 through 5, says Anurag Singh, M.D., a radiation oncologist with the National Cancer Institute’s Center for Cancer Research, because many patients’ nausea is often completely controlled with ondansetron alone.

A question not answered by this study, he explains, is if patients “develop some nausea at the end of treatment, can you still use dexamethasone for rescue?” While dexamethasone reduced nausea and vomiting at the end of treatment in this study, it was administered from the beginning of radiation therapy.

Comments

“Although our study did not demonstrate a statistically significant benefit for the primary end point, (defined as the proportion of patients with complete control of emesis and nausea between days 1 through 5), results on several secondary end points, as well as [quality of life] data, would suggest that benefits do exist with the addition of dexamethasone,” state the authors. They note that in absolute terms, dexamethasone provided an 11 percent benefit in complete control of vomiting and a 6 percent benefit in complete control of nausea for the study period of 15 days.

Still, says NCI’s Singh, the addition of dexamethasone to ondansetron should be evaluated on a patient-by-patient basis because some patients will tolerate steroid drugs better than others, depending on their general state of health.

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