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2003, Number 2

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Acta Med 2003; 1 (2)

Fractional stereotactic radiotherapy or One-dose stereotactic radiotherapy (radiosurgery) in treatment of pituitary adenomas

García SM

Language: Spanish
References: 20
Page: 97-101
PDF size: 54.70 Kb.


ABSTRACT

Pituitary tumors have different pathologic types that cause neurologic, endocrine, or mixed clinical manifestations. Sterotactic radiotherapy delivers with precision a high dose of ionizing radiation to a small target volume of pathologic tissue while protecting the neighboring normal tissues. It can be delivered with 60Co gamma rays or with photons from a linear accelerator, in one dose (ODSR) or in fractionate dosis (FDSR). Stereotactic radiotherapy is prescribed as an adjuvant to surgery, complementary to surgery, primary palliative, and in prolactin-producing adenomas. Planning stereotactic radiotherapy is a complex procedure that requires strict quality control in all stages. The administered doses are specific for each technique. In functioning adenomas criteria to accept a cure are strict. Surgery offers the best results in the short term. After stereotactic radiotherapy, cure is delayed from 18 months to 6 years; medical treatment is needed throughout this time. Rate of cure is 67%. In adenomas with mass effect, surgical decompression improves symptoms in a few months, but 30 to 50% of patients have recurrences. Administering stereotactic radiotherapy after surgery diminishes recurrences to 10%, with a 75% control rate at 5 years and 10 to 20% of recurrences over the same period. When comparing ODSR with FDSR, it is found that at present statistical evidence for therapeutic effect and complications and sequels of ODSR is not reliable. ODSR has an advantage in stabilizing functioning adenomas in the short term. There are no long-term results comparing ODSR with FDSR. Based on present-day results, it is rather improbable that ODSR will surpass FDSR results after 10 years. Stereotactic radiotherapy late complications, and sequels are usually permanent and require treatment or rehabilitation. Risk of complications and sequels is related to dose/volume of tissues and organs exposed. Frequency of neurologic lesions is higher with ODSR that with FDSR. Risk of developing endocrine sequels is also higher with ODSR than with FDSR. There is a need to carry on well-designed prospective clinical research to know the relative value of each modality of stereotactic radiotherapy in treatment of pituitary adenomas.


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