Purpose
Radiation-induced taste and smell disturbances are prevalent in patients receiving brain radiotherapy, although the mechanisms underlying these toxicities are poorly understood. We report the results of a single institution prospective clinical trial aimed at correlating self-reported taste and smell disturbances with radiation dose delivered to defined areas within the brain and nasopharynx.
Methods and Materials
22 patients with gliomas were enrolled on a prospective observational trial in which patients underwent a validated questionnaire assessing taste and smell disturbances at baseline, and at 3 and 6 weeks after commencement of brain radiotherapy. 14 patients with glioblastoma, 3 patients with grade 3 gliomas, and 5 patients with low grade gliomas participated. Median dose to tumor volume was 60 Gy (range 45–60 Gy). Dose volume histogram (DVH) analysis was performed for specific regions of interest (ROI) that were considered potential targets of radiation damage including the thalamus, temporal lobes, nasopharynx, olfactory groove, frontal pole and periventricular stem cell niche. The %v10 (percent of ROI receiving 10 Gy), %v40, and %v60 were calculated for each structure. Data from questionnaires and DVH were analyzed using stepwise regression.
Results
20 of 22 patients submitted evaluable questionnaires that encompassed at least the entire radiotherapy course. 10 of 20 patients reported experiencing some degree of smell disturbance during radiotherapy, and 14 of 20 patients experienced taste disturbances. Patients reporting more severe taste toxicity also reported more severe toxicities with sense of smell (r2=0.60, p<0.006). Tumor location in the temporal lobe predicted for increased severity of taste toxicity (F3, 16=1.44, p<0.06). The nasopharynx was the only structure in which the DVH data predicted the presence of radiation-induced taste changes (r2=0.28, p<0.02).
Conclusions
Radiation-induced taste toxicity appears to be more common in temporal lobe tumors, and may be related to the dose received by the nasopharynx.
Background
Cumulative exposure to alkylating agents may produce impaired reproductive function. Temozolomide is an alkylating agent approved for treating malignant gliomas.
Objective
A pilot study was undertaken to investigate the effects of temozolomide on semen integrity in men with newly diagnosed or recurrent malignant gliomas.
Methods
Eligible patients had no known fertility problems or impotence. Comprehensive semen analysis and serum sex hormones were obtained at baseline and following 3 and at least 6 months of temozolomide.
Results
Thirteen men were recruited. Mean age was 42 years (28–58). Three had recurrent and 10 newly diagnosed malignant glioma. Four were unable to ejaculate or were azoospermic at baseline. Four provided samples at baseline and after at least 6 months of temozolomide. Five were unable to complete the study. Two of four patients with paired baseline and 6-month samples received 6 months of standard monthly temozolomide. Two patients received standard radiation and concurrent temozolomide followed by adjuvant temozolomide. At 6 months, three of these four patients demonstrated low sperm motility (two low at baseline); three had abnormally low percent normal forms (one abnormal at baseline); two developed abnormally low sperm density. Sex hormone values were normal in all four patients at all time points.
Conclusion
Changes in semen analysis parameters following 6 months of temozolomide were observed. The small sample size precludes any firm conclusions regarding the importance and duration of these findings and their relation to temozolomide exposure. With validation in a larger study, these results may have important implications for counseling prior to initiation of temozolomide therapy in these patients.
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