Artikel
Radiosurgery (RS) and stereotactic radiotherapy (SRT) for residual or recurrent pituitary adenomas
Radiochirurgie (RS) und stereotaktische Radiotherapie (SRT) bei Rest- oder Rezidiv-Hypophysenadenomen
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Autoren
Veröffentlicht: | 4. Mai 2005 |
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Gliederung
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Objective
RS as a single high dose and SRT as a fractionated dose delivery, both are highly precise stereotactic radiation techniques which ensure reduction of the normal tissue volume being irradiated compared to conventional external radiation therapy. Therefore RS or SRT should be used if radiotherapy was chosen to treat growing residual or recurrent pituitary adenomas.
Methods
Between May 2000 and May 2004, 51 patients with residual or recurrent pituitary adenomas were treated, among them 16 (14 secretory) small adenomas with RS (distance from visual pathways 6 mm) and 35 (5 secretory) adenomas in close proximity to or even compressing the optic chiasm with SRT. The results until now with a mean follow-up of 36 months (10-54 mo.) were analysed. In case of the RS-treated patients the tumour volumes ranged from 0.1 to 2.2 ccm and the delivered prescription isodose (80%) reached 12-16 Gy. The 35 patients treated with SRT (their irregular tumour volume ranged from 2.2 to 62.7 ccm) received a total dose of 50–54 Gy in standard fractions of 1.8 or 2 Gy per fraction (isocenter dose values).
Results
Until now, no tumour growth occurred. A tumour regression (more than 20%) was proved in 5/16 RS-treated and in 21/35 SRT-treated cases. 2 patients developed a mild increase in visual disturbances on the most affected eye, in 6 cases visual function improved. No patient got a new neurological deficit. Decreased or normal serum hormone values were seen in 5/14 cases with secretory adenomas after RS, in 2/5 cases after SRT.
Conclusions
For residual or recurrent pituitary adenomas, RS and SRT are low risk and effective treatment options for tumour control, but less effective for hormonal normalization. Due to the slow radiobiological effects, RS and SRT are more recommended for nonsecreting adenomas. Particularly in cases with cavernous sinus-invading tumours, RS or SRT can be the treatment of choice.