Jana Ježková

Gamma knife radiosurgery for acromegaly – long‐term experience

Objective  The Leksell gamma knife (LGK) is one of the treatment options for pituitary adenomas. We report on our long‐term experience treating acromegaly using LGK.

Radiation Tolerance of Functioning Pituitary Tissue in Gamma Knife Surgery for Pituitary Adenomas

OBJECTIVEThis study is intended to contribute to a determination of the sensitivity of preserved hypophyseal function to focal radiation in pituitary adenomas. METHODSWe compared two subgroups of patients followed up for a median of 5 years after gamma knife surgery (GKS). Subgroup 1 (n = 30) showed postirradiation hypopituitarism. Subgroup 2 (n = 33) was continually eupituitary. These subgroups were taken from a previously published study relating to a larger group of 163 patients with pituitary adenomas treated by GKS and evaluated after a median follow-up period of 2 years. A relatively high treatment dose was used in this larger group (median, 20 Gy to the tumor margin for growth control in nonfunctioning adenomas; median, 35 Gy for hypersecreting adenomas). Early results approached those of microsurgery, and there were only a few side effects. In the present study, we compared 16 different variables in the same two subgroups to discover the relationships that caused a delayed appearance of postirradiation hypopituitarism. The main pretreatment and treatment parameters were measured on reconstructed treatment plans. This database was used for statistical evaluation. RESULTSThe relationship between the mean dose and the volume of functioning hypophysis was stronger in terms of worsening of pituitary function than that of the spot dose to different intrasellar structures. We found that for our group of patients, the safe mean dose of radiation to the hypophysis was 15 Gy for gonadotropic and thyrotropic functions and 18 Gy for adrenocorticotropic function. The worsening of pituitary function was also significantly dependent on the dose to different anatomic levels of the infundibulum, but we did not succeed in fully characterizing this relationship. In addition, we discovered significant levels of dependency of postirradiation pituitary damage to different pretreatment and treatment variables. CONCLUSIONKnowledge of the radiation tolerance of functioning pituitary structures subjected to GKS can ensure better preservation of pituitary function after irradiation. This is valid for the group of patients we studied. Our study’s findings can be used as a guideline for GKS treatment of new patients with pituitary adenomas, and it can serve for comparison with the experience of other gamma knife centers.

Use of the Leksell gamma knife in the treatment of prolactinoma patients

Objective  Pharmacological treatment with dopaminergic agonists (DA) is the treatment of choice for prolactinomas. Surgical and radiation treatment is also indicated in certain situations. We describe our 12‐year experience in treating prolactinomas with the Leksell gamma knife (LGK).

Is it possible to avoid hypopituitarism after irradiation of pituitary adenomas by the Leksell gamma knife

OBJECTIVE Radiation therapy is one of the treatment options for pituitary adenomas. The most common side effect associated with Leksell gamma knife (LGK) irradiation is the development of hypopituitarism. The aim of this study was to verify that hypopituitarism does not develop if the maximum mean dose to pituitary is kept under 15 Gy and to evaluate the influence of maximum distal infundibulum dose on the development of hypopituitarism. DESIGN AND METHODS We followed the incidence of hypopituitarism in 85 patients irradiated with LGK in 1993-2003. The patients were divided in two subgroups: the first subgroup followed prospectively (45 patients), irradiated with a mean dose to pituitary <15 Gy; the second subgroup followed retrospectively 1993-2001 and prospectively 2001-2009 (40 patients), irradiated with a mean dose to pituitary >15 Gy. Serum TSH, free thyroxine, testosterone or 17β-oestradiol, IGF1, prolactin and cortisol levels were evaluated before and every 6 months after LGK irradiation. RESULTS Hypopituitarism after LGK irradiation developed only in 1 out of 45 (2.2%) patients irradiated with a mean dose to pituitary <15 Gy, in contrast to 72.5% patients irradiated with a mean dose to pituitary >15 Gy. The radiation dose to the distal infundibulum was found as an independent factor of hypopituitarism with calculated maximum safe dose of 17 Gy. CONCLUSION Keeping the mean radiation dose to pituitary under 15 Gy and the dose to the distal infundibulum under 17 Gy prevents the development of hypopituitarism following LGK irradiation.

Intraoperative Magnetic Resonance Imaging During Endoscopic Transsphenoidal Surgery of Growth Hormone-Secreting Pituitary Adenomas

BACKGROUND The effect of intraoperative magnetic resonance imaging (iMRI) on the extent of sellar region tumors treated endonasally has been described in previous research. However, the effects of iMRI on endocrinologic outcome of growth hormone-secreting adenomas have been studied in only a few small cohort studies. METHODS Inclusion criteria were primary transsphenoidal surgery for growth hormone-secreting adenoma from January 2009 to December 2014, a minimum follow-up of 1 year, complete endocrinologic data, at least 1 iMRI, and at least 2 postoperative magnetic resonance images. The cohort consisted of 105 patients (54 females, 51 males) with a mean age of 48.3 years (range, 7-77 years). There were 16 microadenomas and 89 macroadenomas. RESULTS Endocrinologic remission in the whole cohort was achieved in 64 of the patients (60.9%). Resection after iMRI was attempted in 22 of the cases (20.9%). Resection after iMRI led to hormonal remission in 9 cases (8.6%). Endocrinologic postoperative deficit was observed in 10 cases (12.5%). Postoperative cerebrospinal fluid leakage indicated the necessity to reoperate in 3 cases (3.8%). No neurologic deterioration was observed. CONCLUSIONS iMRI influences not only the morphologic extent of pituitary adenomas resection but also the endocrinologic results. We encourage the routine application of iMRI in pituitary adenoma surgery, including hormone-secreting pituitary tumors.

Diagnosis and treatment of prolactinomas

Prolactinomas account for approximately 40% of all pituitary adenomas. Hyperprolactinemia causes hypogonadism, infertility and galactorrhea. Macroprolactinomas may cause signs of local expansion, such as headache, visual field defects and paresis of oculomotor nerves during suprasellar and parasellar extensions. Compression of healthy pituitary tissue together with the blockade of the flow of hypothalamic released hormones to the pituitary by macroprolactinomas results in the development of hypopituitarism. The aim of treatment is restoration of hypogonadism and fertility in the microprolactinoma patients, as well as tumor shrinkage in macroprolactinoma patients. Primary therapy for prolactinomas is pharmacological treatment with dopamine agonists (DAs). However, surgical or radiation treatment is recommended for prolactinoma patients resistant or intolerant to DAs. In patients with long-term normoprolactinemia and significant tumor shrinkage, a trial of tapering and discontinuation of medical therapy is possible. After discontinuation of DAs, a long-term follow-up is necessary. In cases of recurrence displaying hyperprolactinemia and tumor enlargement, treatment must be resumed.