EKSTERNAL IRRADIATION OF PITUITARY ADENOMAS WITH ARC TECHNIQUE

In the management of pituitary adenomas, radiotherapy is used postoperatively or primary due to inoperability. Arc therapy is one of the treatment techniques for small, centrally located deep-seated tumors. During the period between 1996 and 1998, a total of 12 patients with pituitary adenomas were treated in our department. 4 patients with bilateral opposed fields and 8 patients with bilateral arc rotation were irradiated using 15-25 MV photons with a Linear accelerator. Mean clinical follow-up was 35 months (8-56 months). Visual improvement which is the one of the purpose of the treatment was achieved for 10 patients (83%). Overall response rate observed radiologically was achieved by 83%. Median lens doses were obtained by 90 cGy in patients with arc therapy while 310 cGy with bilateral opposed fields (P<0.01). Treatment complications were not seen in any patients during follow-up. Bilateral arc rotation seems to better dose distribution for target volume while sparing dose to critical organs like lens.

Keywords: pituitary adenoma, arc technique, radiotherapy