Cerebral necrosis after 25Gy radiotherapy in childhood followed 28 years later by 54Gy radiotherapy.

The development of brain necrosis is life-long risk of repeat radiation therapy, even after a long time interval and a moderate radiation dose. We report on a 34-year-old patient who had prophylactic cranial irradiation with 25Gy and adjuvant chemotherapy in childhood for leukaemia and in adulthood, 28 years later, therapeutic radiotherapy with 54Gy for an atypical (WHO grade II) meningioma. About 2 years later he developed a contrast-enhancing lesion on MRI-scan that was indicative of a tumor according to a thallium-201 ((201)Tl) SPECT scan. Histopathology of the operated contrast-enhancing lesion showed extensive radionecrosis. Radiation necrosis is a small but serious risk after repeat radiation therapy, even after a very long-term interval, the delivery of small fractions and an average cumulative total dose. Patients undergoing repeat radiotherapy therefore need to be followed life-long for potential late radiation toxicity.

Hypofractionation in glioblastoma multiforme.

PURPOSE: To compare conventional fractionation with hypofractionation in patients with a glioblastoma multiforme. Endpoints of the analysis are overall survival and palliative effect. MATERIALS AND METHODS: From 1988 to 1998, 155 patients with pathologically confirmed glioblastoma multiforme were prospectively analysed. Patients without irradiation and patients receiving an interstitial boost were excluded from this analysis. Three different radiation schemes were used in subsequent periods; 33x2, 8x5 and 4x7 Gy. In the last 5 years a scheme of 4x7 Gy conformal irradiation was given to poor prognosis patients. The more favourable group received the conventionally fractionated scheme up to 66 Gy. RESULTS: Median survival was 7, 5.6 and 6.6 months for the 33x2, 8x5 and 4x7 Gy, respectively. In general, patients in the hypofractionation group had far worse prognostic factors compared with patients treated with the conventional scheme. The period of neurological improvement or stabilisation was similar between the 4x7 and 33x2 Gy group. CONCLUSION: An extreme hypofractionation scheme of 4x7 Gy conformal irradiation in poor prognostic glioblastoma patients is well tolerated, convenient for the patient and provides equal palliation without negative effects on survival compared with conventional fractionation.

Perineural tumor extension along the trigeminal nerve: magnetic resonance imaging findings.

OBJECTIVE: To evaluate the magnetic resonance imaging (MRI) findings of 15 patients with perineural tumor extension along the trigeminal nerve in correlation with clinical data. METHODS: The clinical records and MRI studies of 15 patients with perineural tumor extension along the trigeminal nerve were retrospectively reviewed. Imaging studies included plain and contrast-enhanced thin section T1-weighted spin echo (T1-WSE) MRI with and without fat-suppression. The studies were compared to determine which sequence provided greatest tumor conspicuity and best depiction of tumor extent. The conspicuity of these tumors was assessed on the available sequences by two observers by consensus. RESULTS: The contrast-enhanced T1-weighted spin echo fat-suppressed images (T1-WSECEFS) demonstrated greatest tumor conspicuity and best depiction of tumor extent in the extracranial head and neck and skull base region. The conventional T1-weighted spin echo pre- and postcontrast images were, however, diagnostic of perineural tumor extension in 11 patients due to the presence of considerable tumor bulk and extension well above the skull base. In the other four patients the perineural tumor was poorly visualized on the conventional T1-WSE images and well visualized on the fat-suppressed images. The mandibular division of the trigeminal nerve (V3) was most commonly involved (n = 10), followed by the maxillary (V2; n = 5) and ophthalmic (V1; n = 2) division. Two patients had both mandibular as well as maxillary nerve involvement. The finding of perineural tumor extension had significant impact on patient management: based on the MR imaging study, the primary tumor was considered inoperable (n = 13), the extent of surgery was expanded (n = 2) and radiation therapy (RT) ports were extended (n = 12). CONCLUSION: Complete trigeminal nerve imaging is recommended when evaluating (suspected) head and neck malignancies with a high risk for perineural extension. In these cases thin section axial and coronal precontrast T1-WSE MR images and postcontrast T1-WSE MR images with fat-suppression should be obtained. In the rare event that artifacts degrade the quality of the fat-suppressed images, contrast-enhanced T1-WSE sequences without fat-suppression can additionally be used.