Most neurological lesions in cancer patients are progressive, have a profound influence on the quality of life and are life threatening. Management of the situation requires rapid identification of the nature and location of the problem as the treatment outcome depends as much on the speed ofdiagnosis as on the subsequent therapy. While modern neuroimages provides invaluable clues to the diagnosis, they need to be interpreted in the light of clinical data. The clinical examination remains the cornerstone of the differential diagnosis of neurological lesions affecting the cancerpatient. Neurological disorders are a consequence not only of primary tumours of the central and peripheral nervous system but also of systemic malignancy. One in five patients with disseminated malignancy develop neurological complications other than neurogenic pain. The majority of neurologicalproblems are a direct consequence of metastatic disease or the result of metabolic disorders; however, some disorders are due to anti-neoplastic treatments or the administration of drugs. The incidence of CNS infections and vascular lesions is also increased in malignant disease, and a smallproportion of neurological disorders are paraneoplastic, resulting from a remote effect of cancer on the nervous system. This book, written by a neurologist and an oncologist, aims to help the clinician to identify and locate the underlying neurological lesion in a cancer patient, and to make aquick therapeutic decision. Diagnostic and therapeutic algorithms are included with an emphasis on the more common and potentially treatable conditions. It should be read by neuro-oncologists, medical oncologists, radiation therapists, neurosurgeons and all those involved in the management ofcancer patients.

Abstract: Background and purpose For skull base tumors, target definition is the key to safe high-dose treatments because surrounding normal tissues are very sensitive to radiation. In the present work we established a joint ESTRO ACROP guideline for the target volume definition of skull base tumors. Material and methods A comprehensive literature search was conducted in PubMed using various combinations of the following medical subjects headings (MeSH) and free-text words: "radiation therapy" or "stereotactic radiosurgery" or "proton therapy" or "particle beam therapy" and "skull base neoplasms" "pituitary neoplasms", "meningioma", "craniopharyngioma", "chordoma", "chondrosarcoma", "acoustic neuroma/vestibular schwannoma", "organs at risk", "gross tumor volume", "clinical tumor volume", "planning tumor volume", "target volume", "target delineation", "dose constraints". The ACROP committee identified sixteen European experts in close interaction with the ESTRO clinical committee who analyzed and discussed the body of evidence concerning target delineation. Results All experts agree that magnetic resonance (MR) images with high three-dimensional spatial accuracy and tissue-contrast definition, both T2-weighted and volumetric T1-weighted sequences, are required to improve target delineation. In detail, several key issues were identified and discussed: i) radiation techniques and immobilization, ii) imaging techniques and target delineation, and iii) technical aspects of radiation treatments including planning techniques and dose-fractionation schedules. Specific target delineation issues with regard to different skull base tumors, including pituitary adenomas, meningiomas, craniopharyngiomas, acoustic neuromas, chordomas and chondrosarcomas are presented. Conclusions This ESTRO ACROP guideline achieved detailed recommendations on target volume definition for skull base tumors, as well as comprehensive advice about imaging modalities and radiation techniques