[The use of granisetron per os in radiotherapy-induced emesis]

Radiation-induced emesis is a quite frequent event when total and half body irradiation or wide fields on the pelvis, abdomen and mediastinum are employed. These symptoms cannot always be controlled by dopamine antagonists as metoclopramide. In these cases the use of 5-HT3 antagonist, widely employed during chemotherapy, can be studied.

We examined 15 patients, 8 males and 7 females, aged 23-79 (mean 49, median 54), with performance status = < 2 (ECOG): 4 seminomas of the testis, 4 cervical carcinomas, 3 recto-sigmoid adenocarcinomas, 2 Hodgkin's lymphomas, 1 prostate adenocarcinoma and 1 lung carcinoma. Radiotherapy was performed on the pelvis in 7 cases, on the lumboaortic and iliac regions in 4 cases, on the lumboaortic and splenic regions in 2 cases, on the lumboaortic region in 1 case and on the mediastinum in 1 case using X-rays of linear accelerator (18 MV). Usual doses and conventional fractionation were employed. During treatment we observed nausea and vomiting grade 2 (RTOG scale) uncontrolled by dopamine antagonists. These symptoms appeared 1-41 days (mean 13.5, median 7) after the start of the radiotherapy, at doses of 1.8-49 Gy (mean 16.7 Gy, median 9 Gy). In all cases we administered oral granisetron 1 mg/day 1-2 hours prior to radiotherapy (5 days/week).

In all patients we observed complete remission of the symptoms in 1-3 days (mean 1.5, median 1). Thirty-three % of the patients had an immediate remission of nausea and vomiting. Granisetron was administered 7-28 days (mean 16.3, median 14). The compliance to the treatment was optimal: 100% in the first week. No adverse events were observed.

The mechanism of radiation-induced emesis is not well known but some studies showed that 5-HT3 receptors are involved, as well as demonstrated for chemotherapy. Age, performance status, anxiety, concomitant pathologies, size of radiation fields and dose fractionation probably play an important role. Most studies concern the use of intravenous granisetron for emesis during total body of half body irradiation and conclude that this drug is very effective in prevention and treatment of this symptom. In our series we observed a very high efficacy of oral granisetron in the treatment of nausea and vomiting during irradiation by wide fields on the pelvis, abdomen and mediastinum, without adverse events. We conclude that the administration of oral granisetron can be effective and useful for radiation-induced emesis when dopamine antagonists have failed.