Evaluation of histopathological findings at the injection site following degarelix administration

Purpose: The aims of the present study were to investigate the incidence of injection site reactions (ISRs) following administration of 240 mg degarelix and identify the risk factors for ISRs. Methods: This study was conducted in 50 consecutive men treated with degarelix for the first time. ISRs after an initial degarelix dose of 240 mg (administered subcutaneously as two 3 ml subcutaneous injection) were evaluated using the five categories of the Common Terminology Criteria for Adverse Events Version 4 of the National Cancer Institute. We also assessed the differences in patient background between patients with and without an ISR. Results: The mean age of patients and prostate-specific antigen (PSA) level just before degarelix administration were 75.6 and 198.4 ng/ml, respectively. Hormonal therapy with degarelix was administered for the first time to 33 patients; 11 of the 50 patients were receiving an oral steroid, 6 for prostate cancer, 1 for hematological disease, and 4 for allergic conditions. ISRs were observed in 25 patients, and all of the ISRs were categorized as grade 1 or 2; however, 2 patients discontinued this procedure due to the ISR. Significant differences in the first experience with subcutaneous therapy (p = 0.007) and rate of combination with a steroid (p = 0.017) were observed between patients with and without ISRs. Conclusion: The incidences of ISRs in patients receiving subcutaneous therapy for the first time and in patients also receiving an oral steroid were 64 and 18 %, respectively. Patients should be provided with information concerning the possible occurrence of ISR due to degarelix prior to the administration, particularly patients who are not receiving steroids and patients who have no experience with subcutaneous injections.