Short communicationCranial nerve palsies in metastatic prostate cancer—results of base of skull radiotherapy
Introduction
The skull is a common site for metastatic spread in prostate cancer [2], which can lead to very distressing and debilitating symptoms including cranial nerve palsies when the neural-foramina are compromised by tumour growth or new bone formation. Cranial nerve palsies can be single or multiple and may be confused with meningeal carcinomatosis or infection. Metastatic spread of prostate cancer to the parenchyma of the brain is very rare [5] and therefore cranial nerve compromise is most likely due to metastases to the bone of the skull.
The diagnosis of skull base metastases can usually be made using isotope bone scan; however, CT or MRI may be needed for confirmation especially if there is a significant soft tissue component [1], [5]. In a study of 32 cases of skull base metastasis (SBM), radiological confirmation of metastatic spread to the base of skull was found in only 77% of patients [3]. It is therefore often necessary to make the diagnosis of SBM on clinical grounds.
Cranial nerve dysfunction caused by SBM is traditionally treated by mega-voltage (MV) external beam radiation therapy using parallel-opposed beams in conjunction with high dose corticosteroids. Due to the relative infrequency of the syndrome in prostate cancer and its occurrence late in the course of the disease, very little data exists on the response and toxicity of therapy. We performed this analysis in order to better define the role of external beam radiotherapy in the management of the condition.
Section snippets
Materials and methods
We examined the Royal Marsden Hospital prostate cancer database for patients with prostate cancer who were treated with external beam radiotherapy to the base of skull between 1st January 1995 and 31st December 2002. Patient case notes were then examined in order to determine the reason for base of skull radiotherapy. All patients with documented cranial nerve palsy were included. Data obtained included radiological findings, radiation dose and fractionation, and response to treatment.
Response
Statistics
The method of Kaplan and Meier was used to determine actuarial survival [4]. Stepwise logistic regression analysis was used to perform multivariate analysis of factors predicting for a response to therapy. A P value <0.05 was regarded as statistically significant.
Results
A total of 32 patients with a median age of 73 years (range 49–85) were identified as fulfilling the inclusion criteria. Patient characteristics are demonstrated in Table 1. Patients in the cohort had a median of three previous hormone manipulations at the time of base of skull radiotherapy and all had failed first line androgen deprivation therapy. Ten patients (31%) had documented nodal metastases and three (9%) had lung metastases. The median survival following base of skull radiotherapy was
Discussion
This study represents the largest series to our knowledge of patients with metastatic prostate cancer causing cranial nerve dysfunction. In this cohort external beam radiation therapy in combination with high dose steroids is shown to be an effective treatment with a 50% overall response rate. This response rate, while relatively good considering the advanced nature of the disease, is lower than expected from previous reports in the literature. Svare et al. [7] described 11 patients with
Acknowledgements
This work was undertaken in The Royal Marsden NHS Trust who received a proportion of its funding from the NHS Executive; the views expressed in this publication are those of the authors and not necessarily those of the NHS Executive. This work was supported by the Institute of Cancer Research, the Bob Champion Cancer Trust and Cancer Research UK Section of Radiotherapy.
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