PARTICLE-BEAM THERAPY (HADRONTHERAPY) - BASIS FOR INTEREST AND CLINICAL-EXPERIENCE

The particle or hadron beams deployed in radiotherapy (protons, neutro ns and helium, carbon, oxygen and neon ions) have physical and radiobi ological characteristics which differ from those of conventional radio therapy beams (photons) and which offer a number of theoretical advant ages over conventional radiotherapy. After briefly describing the prop erties of hadron beams in comparison to photons, this review discusses the indications for hadrontherapy and analyses accumulated experience on the use of this modality to treat mainly neoplastic lesions, as pu blished by the relatively few hadrontherapy centres operating around t he world. The analysis indicates that for selected patients and tumour s (particularly uveal melanomas and base of skull/spinal chordomas and chondrosarcomas), hadrontherapy produces greater disease-ti ee surviv al. The advantages of hadrontherapy are most promisingly realised when used in conjunction with modern patient positioning, radiation delive ry and focusing techniques (e.g. on-line imaging, three-dimensional co nformal radiotherapy) developed to improve the efficacy of photon ther apy. Although the construction and running costs of hadrontherapy unit s are considerably greater than those of conventional facilities, a co mprehensive analysis that considers all the costs, particularly those resulting from the failure of less effective conventional radiotherapy , might indicate that hadrontherapy could be cost effective. En conclu sion, the growing interest in this form of treatment seems to be fully justified by the results obtained to date, although more efficacy and dosing studies are required. (C) 1998 Elsevier Science Ltd. All right s reserved.