Radiotherapy of pituitary adenomas: state of the art

[Stereotactic radiotherapy of intracranial benign tumors]

Stereotactic radiotherapy can be delivered in one fraction or in multiple fractions schedule. It is used in benign tumours such as meningiomas, mainly localized in the base of the skull, for acoustic schwannoma and pituitary tumours. Whatever the tumour, results with the Gamma Knife(®) are the most numerous, but those obtained by linear accelerators, adapted or dedicated, are comparable. The peripheral dose is preferred to the dose delivered to the isocentre. One fraction stereotactic irradiation should be proposed in small lesions and fractionated treatment for tumours larger. Whatever the tumour, the results are satisfactory with a control rate of 90%. However, this value reflects a disparity assessment, radiological stability for meningiomas, radiological stability and preservation of useful hearing in schwannoma and radiological stability and a decrease in hormonal secretions for pituitary adenomas. Overall complication rates are low. In total, the treatment of benign lesions with stereotactic irradiation gives satisfactory results with few complications.

Transcranial approach to pituitary adenomas invading the cavernous sinus: A modification of the classical technique to be used in a low-technology environment

Objective:

Pituitary adenomas invading the cavernous sinus represent a therapeutic challenge. Those tumors have been traditionally treated with incomplete surgical removal, observation and/ or adjunctive medical therapy, and radiotherapy. In relatively recent years, some authors have suggested a main direct surgical approach to cavernous sinus (CS) with the aim of complete removal of the adenoma, either by a modified trans-sphenoidal route, using or not an endoscopy-assisted approach, or by a transcranial direct approach. The latter has the advantage of allowing direct exposure of the lesion with a view of the surgical field unhindered by important neurovascular structures.

Materials and Methods:

We report a technical modification of the classical epidural approach for CS adenoma removal. This was used in 14 patients. Surgical technique included a fronto-orbito-zygomatic craniotomy with extradural anterior clinoidectomy, and intradural approach to the Hakuba’s triangle for intracavernous dissection. The tumors were removed under direct vision.

Results:

Total macroscopical removal was achieved in all but one case. This patient required postoperative radiation therapy as well as adjuvant dopaminergic regime for achieving control of preoperatively increased hormonal values. No other case required radiotherapy. Hormonal and/ or clinical control was also achieved in all the remaining cases. Out of the remaining 13 cases, all appeared to be tumor free at an average postoperative observation at 78 months (34 to 90 months). Significant surgical sequels were detected in only 1 case (persistent 3^rd nerve palsy and moderate hemiparesis).

Conclusions:

This experience, though limited, would suggest that the transcranial limited CS exposure through the Hakuba’s triangle may allow adequate removal of intracavernous pituitary adenomas with very good long-term results and acceptable complication rate.