Incidence of acute peripheral neurotoxicity after deep regional hyperthermia of the pelvis

Background: After observing rather severe acute neurotoxicity in a few patients following deep hyperthermia treatment for a pelvic turnout, we evaluated the incidence of neurotoxicity in all patients treated with deep hyperthermia of the pelvis between June 1990 and April 2004. Materials and methods: Hyperthermia treatment registrations and hospital charts of all 736 patients were reviewed. Differences between the incidence of neurotoxicity in subgroups of patients were evaluated by 2 x 2 exact tests. Results: Grade 2 or 3 acute neurotoxicity occurred in 2.3% of patients, grade 3 in 0.7%. The duration of symptoms was longer than 3 months in 6 patients (0.8%). Neurological examination in 5 patients showed that the most commonly involved structures are the sacral and lower lumbar nerve roots and the sacral plexus. Acute neurotoxicity occurred only after November 1999 and only in patients treated for primary cervical cancer. Comparison of applied powers and achieved temperatures in patients developing neurotoxicity did not show differences between treatment sessions which resulted in neurotoxicity and sessions not resulting in neurotoxicity. Conclusion: Acute neurotoxicity following hyperthermia for pelvic tumours is a rare complication, but can result in symptoms affecting the activities of daily life. We found no patient, tumour or treatment characteristics predictive for a risk of neurotoxicity.