Treatment of prolactinomas with megavoltage radiotherapy

Challenges and controversies in the treatment of prolactinomas

Recent studies have reported a higher prevalence of pituitary tumors than previously thought. Among these tumors, prolactinomas occur in up to 66% of cases. Since the mid-1980s, the widespread use of dopamine agonists has facilitated the management of the majority of prolactinomas, allowing biological and tumoral control in most cases. The less frequent cases of resistant prolactinomas remain challenging despite a multimodal therapy approach. The understanding of genetic alterations in familial and aggressive pituitary tumors provides new perspectives in the management of some prolactinomas. Genetic screening should be considered, particularly in familial cases but also in young patients with macroprolactinomas, as some mutations can predict potential aggressiveness.

Radiotherapy for prolactin-secreting pituitary tumors

Review the medical and surgical management of patients with prolactinomas and provide an in-depth appraisal of the role of radiotherapy in the treatment of prolactinomas. A thorough review of the pertinent literature was carried out and relevant topics were identified. Topics covered in this comprehensive review include: indications for the use of radiotherapy, choice between conventional radiotherapy and stereotactic radiosurgery, as well as the benefits and potential complications associated with each modality. Due to the excellent response rates with medical management, and rapid symptom relief afforded by resection or debulking surgery in patients who do not respond or tolerate medical therapy, radiotherapy is reserved for patients who do not respond to dopamine agonists and surgery. Both external beam radiotherapy and stereotactic radiosurgery retain important roles in the treatment of refractory or recurrent prolactinomas. Choosing the optimal approach is crucial in maximizing tumor control outcomes and minimizing the risks associated with treatment. The primary determinants of optimal radiation approach are proximity of the tumor to the optic apparatus and tumor size, with radiosurgery being our recommended treatment of choice unless the tumor is larger than 3-4 cm or within 3 mm of the optic nerves, chiasm or tracts. Optimal multidisciplinary management requires the identification of appropriate candidates for radiotherapy in order to take full advantage of treatment options available for each patient.

Radiotherapy in paediatric Cushing's disease: efficacy and long term follow up of pituitary function

Pituitary radiotherapy (RT) is an effective second-line treatment for paediatric Cushing's disease (CD). We report long-term efficacy and anterior pituitary function in a cohort of paediatric CD patients treated with RT. Between 1988 and 2008, from our cohort of 48 paediatric CD patients, eight paediatric CD patients (5 males and 3 females) underwent second-line pituitary RT (45 Gy in 25 fractions), following unsuccessful transsphenoidal surgery. Out of eight whose long term follow up is available, four patients were cured by RT. Minimum follow up of 2 years is available for all patients. Four patients achieved cure after RT. Two patients were not cured even after follow up of 60 and 132 months, respectively. Out of four uncured patients, two of them had suppressible low dose dexamethasone cortisol with altered circadian rhythm suggesting possibility of response in near future with follow up of just 26 months. Five patients were hypogonadal and one patient was hypothyroid. All patients were below their target height at the time of last follow up. None of the patients had posterior pituitary dysfunction. This series of patients illustrates the efficacy and long-term follow up of pituitary function in children with CD treated with RT. This study also emphasizes the need of growth hormone statues assessment and timely intervention.

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).

DESIGN

We followed 35 prolactinoma patients (25.7% microprolactinomas, 74.3% macroprolactinomas) treated with LGK irradiation. The mean follow-up period was 75.5 months. Prior to LGK irradiation, patients were treated with DA and 10 of them (28.6%) underwent neurosurgery. Indications for LGK irradiation were: DA intolerance (31.4%), DA resistance (45.7%) and efforts to reduce the DA dose or shorten the period of administration (22.9%). Pituitary function was monitored regularly at 6-month intervals. The central radiation dose range was 40-80 Gy (median 70 Gy), and the minimal peripheral dose was 20-49 Gy (median 34 Gy).

RESULTS

Normoprolactinaemia was achieved in 37.1% of the patients who discontinued DA and in 42.9% of patients who continued DA treatment after LGK irradiation. The median time to prolactin normalization after discontinuation of DA was 96 months. No relapse was seen in any patient. After LGK irradiation, the prolactinoma stopped growing or decreased in size in all but one patient (97.1%).

CONCLUSION

LGK treatment resulted in normoprolactinaemia in 80.0% of the patients, all of whom had failed pharmacological treatment due to DA resistance or intolerance. After achieving normoprolactinaemia, no relapse of hyperprolactinaemia was observed in any patient. The size of the adenoma decreased even in those patients in whom it was not changed by previous DA treatment.

Applications of radiotherapy and radiosurgery in the management of pediatric Cushing's disease: a review of the literature and our experience

Surgical extirpation of pituitary adenomas is considered the mainstay of therapy in pediatric patients with Cushing's disease. However, a small subset of patients will require adjuvant therapy either due to tumor invasiveness, or disease recurrence. Conventional radiation therapy (or radiotherapy) delivers ionizing radiation to control hormonally active cells in fractionated doses (spread out over time) in order to give normal cells time to recover, while radiosurgery involves focusing a high dose of radiation structures in a single treatment session to the adenoma while generally sparing the normal gland and surrounding of any substantial amount of radiation. This paper reviews the effectiveness of radiation in the treatment of pediatric Cushing's disease.

Intensity-modulated radiotherapy for pituitary adenomas: The preliminary report of the Cleveland Clinic experience

PURPOSE

Intensity-modulated radiotherapy (IMRT) is being increasingly used for the treatment of pituitary adenomas. However, there have been few published data on the short- and long-term outcomes of this treatment. This is the initial report of the Cleveland Clinic's experience.

METHODS AND MATERIALS

Between February 1998 and December 2003, 34 patients with pituitary adenomas were treated with IMRT. A retrospective chart review was conducted for data analysis.

RESULTS

With a median follow-up of 42.5 months, the treatment has proven to be well tolerated, with performance status remaining stable in 90% of patients. Radiographic local control was 89%, and among patients with secretory tumors, 100% had a biochemical response. Only 1 patient required salvage surgery for progressive disease, giving a clinical progression free survival of 97%. The only patient who received more than 46 Gy experienced optic neuropathy 8 months after radiation. Smaller tumor volume significantly correlated with subjective improvements in nonvisual neurologic complaints (p = 0.03), and larger tumor volume significantly correlated with subjective worsening of visual symptoms (p = 0.05). New hormonal supplementation was required for 40% of patients. Younger patients were significantly more likely to require hormonal supplementation (p = 0.03).

CONCLUSIONS

Intensity-modulated radiation therapy is a safe and effective treatment for pituitary adenomas over the short term. Longer follow-up is necessary to determine if IMRT confers any advantage with respect to either tumor control or toxicity over conventional radiation modalities.

Advances in the treatment of prolactinomas

Prolactinomas account for approximately 40% of all pituitary adenomas and are an important cause of hypogonadism and infertility. The ultimate goal of therapy for prolactinomas is restoration or achievement of eugonadism through the normalization of hyperprolactinemia and control of tumor mass. Medical therapy with dopamine agonists is highly effective in the majority of cases and represents the mainstay of therapy. Recent data indicating successful withdrawal of these agents in a subset of patients challenge the previously held concept that medical therapy is a lifelong requirement. Complicated situations, such as those encountered in resistance to dopamine agonists, pregnancy, and giant or malignant prolactinomas, may require multimodal therapy involving surgery, radiotherapy, or both. Progress in elucidating the mechanisms underlying the pathogenesis of prolactinomas may enable future development of novel molecular therapies for treatment-resistant cases. This review provides a critical analysis of the efficacy and safety of the various modes of therapy available for the treatment of patients with prolactinomas with an emphasis on challenging situations, a discussion of the data regarding withdrawal of medical therapy, and a foreshadowing of novel approaches to therapy that may become available in the future.

Hypothalamo-pituitary-adrenal axis integrity after cranial irradiation for childhood posterior fossa tumours

BACKGROUND

The evolution of anterior pituitary deficits after treatment for pituitary tumours has been largely attributed to local irradiation, but may be influenced as much by tumour mass or surgery. Other than growth hormone (GH) insufficiency, the late endocrinopathies after survival from non-central brain tumours have been little documented. The aim of this study was to investigate the hypothalamic-pituitary-adrenal (HPA) axis in long-term survivors of cranial irradiation for childhood posterior fossa tumours.

PROCEDURE

We studied long-term data in patients treated prepubertally for posterior fossa brain tumours and systematically referred by radiation oncologists for growth and pubertal monitoring to the London Centre for Paediatric Endocrinology over the last 25 years. They must have undergone HPA axis assessment twice, first prepubertally at documentation of growth failure, and second at completion of growth and puberty. Data on sixteen patients (12 males, 4 females; median age: 5.7 years, range: 2.5-8.8 years), who had undergone excision surgery with high dose cranial irradiation and/or chemotherapy for childhood posterior fossa tumours, were examined. Patients were followed for a median of 11.0 (range: 6.8-21.4) years after radiotherapy. HPA axis assessment was undertaken with the insulin-induced hypoglycaemia test (ITT). Basal thyroid, cortisol and gonadal function tests were undertaken annually throughout the follow-up period and any deficits replaced.

RESULTS

At each ITT, all patients mounted an inadequate GH response. By the end of the follow-up period all patients remained severely GH deficient, two (12.5%) had partial ACTH insufficiency, one (6.3%) had secondary hypothyroidism but none were gonadotropin deficient or hyperprolactinaemic.

CONCLUSIONS

Unlike the severe, evolving multiple pituitary deficits after treatment of pituitary or central tumours in adults, these findings in children with posterior fossa tumours suggest that, with the exception of GH, neurotoxicity due to irradiation per se is associated with a low prevalence of anterior pituitary hormone deficiencies, even at a long follow-up. Since the children in this study were selected for assessment on the basis of growth failure, the high prevalence of GH insufficiency at first testing is to be expected; however, the early onset (within 1-3 years of irradiation) and permanence we have identified supports the view that GH is the most sensitive hormone to radiation injury.

Growth following malignancy

Disturbed growth in the child surviving cancer is multifactorial. This chapter examines the evidence for, and the difficulties in determining, individual drug treatment or disease effects at multiple endocrine levels influencing growth and against a changing baseline of adjuvant cancer therapies with potentially additive toxicity. The evolutionary pattern and potential aetiology of the neuro-endocrine deficit and growth-plate disturbance, the (unrandomized) effects of hormone replacement therapy and areas which require further study are also addressed. The reasons why growth hormone (GH) secretion is so exquisitely sensitive to disturbance, even though deficiencies soon after lesser cranial insults can be difficult to detect, are explored with evidence cited from the few existing prospective and interventional studies. The extent and nature of the hypothalamo-pituitary disturbance needs further prospective interventional study and disease-site- and treatment-specific comparisons. Practical treatment and surveillance strategies to optimize growth potential, age-appropriate development, peak bone mineral accretion, hair re-growth and future health and well-being are also suggested. Health-related outcomes resulting from today's newer therapies and enhanced surveillance need documenting in future (inter)national cancer trials, where randomized studies of hormonal intervention may also become possible.

Long-term follow-up of prolactinomas: normoprolactinemia after bromocriptine withdrawal

Bromocriptine (BRC) and other dopamine agonist drugs are the first-choice treatment for prolactinomas. However, the major disadvantage is the need for prolonged therapy. We retrospectively studied 131 patients [62 microprolactinoma (MIC), 69 macroprolactinoma (MAC)], who achieved serum prolactin (PRL) normalization during BRC use. Twenty-seven percent of them (31% MIC and 69% MAC) underwent previous surgery. Twenty-seven patients (20.6%: 25.8% MIC and 15.9% MAC) persisted with normoprolactinemia after a median time of 44 months of BRC withdrawal. The median time of BRC use was 47 months. There were no statistically significant differences regarding age, gender, BRC initial dose, length of BRC use, tumor size, pregnancy during treatment, previous surgery, or radiotherapy among patients who persisted with normoprolactinemia and those who did not, using both univariate and multivariate analysis. BRC-induced prolactinoma cell alterations are highly controversial; and so, whether the mechanism of PRL normalization after BRC withdrawal is related to BRC use or whether it is attributable to natural history is a matter for debate. A periodic assessment of PRL levels during BRC (and other dopamine-agonist drugs) withdrawal is recommended to avoid the unnecessary maintenance of therapy in a subset of patients with prolactinomas.

The efficacy of conventional radiation therapy in the management of pituitary adenoma

PURPOSE

To evaluate the efficacy of conventional radiotherapy for reducing tumor size and endocrine hypersecretion of pituitary adenomas.

METHODS AND MATERIALS

We reviewed the records of 91 patients with pituitary adenoma, who were first treated between 1969 and 1994 and had been followed for more than 2 years (median, 8.2 years.) Of these patients, 86 had received postoperative radiotherapy, and 5 had received radiotherapy alone. The median total dose was 51 Gy. Clinical symptoms related to mass effects or endocrine hypersecretion were assessed. The efficacy of radiotherapy was evaluated before treatment and during the follow-up period (1-14 years; median, 3 years) by estimating tumor size on computed tomography or magnetic resonance imaging in 56 patients, as well as by endocrine testing in the 22 patients who had secreting adenomas. Local control rate, prognostic factors, and side effects were analyzed.

RESULTS

Mass-effect symptoms improved in 72% and 79% of patients who had such symptoms due to nonsecreting adenomas and secreting adenomas, respectively. Symptoms of endocrine hypersecretion abated in 67% of patients who had such symptoms. Excessive hormone levels normalized in 74% of patients who showed endocrine hypersecretions. The greatest size reduction was seen 3 years after the completion of radiotherapy (24% CR, 62% PR, 12% NC, and 3% PD in nonsecreting adenomas, and 32% CR, 36% PR, 27% NC, and 5% PD in secreting adenomas). Three patients with secreting adenomas (2 with prolactinoma and 1 with Cushing's disease) showed a mismatch between reduction in tumor size and normalization of endocrine hypersecretion. The 10-year local control rates were 98%, 85%, 83%, and 67% for nonsecreting adenoma, growth-hormone-secreting adenoma, prolactinoma, and Cushing's disease, respectively. Univariate analyses showed that disease type and radiation field size were significant prognostic factors. Brain necrosis occurred in 1 patient who received a 60-Gy dose of irradiation.

CONCLUSION

We conclude that conventional external radiotherapy with 50 Gy is safe and sufficient to control pituitary adenoma. Careful observation is required in the management of secreting adenomas because the effects on tumor size and endocrine hypersecretion may be mismatched in some secreting adenomas.

Growth-hormone and prolactin excess

The treatment of acromegaly and hyperprolactinaemia has been improved by the availability of effective and well-tolerated slow-release somatostatin analogues and dopamine agonists with long-lasting activity, such as cabergoline. The use of these drugs has extended the possibility of treatment to patients who would have responded poorly to the previously available compounds, such as octreotide or bromocriptine, and to those who were intolerant to pharmacotherapy. Moreover, the improvement in the management of acromegaly has enabled the reversal, at least partly, of cardiomyopathy and sleep apnoea, two important risk factors for morbidity and mortality in these patients.

Normal final height and apparent cure after pituitary irradiation for Cushing's disease in childhood: long-term follow-up of anterior pituitary function

Pituitary-dependent Cushing's syndrome is rare in childhood. Two patients are reported who had unsuccessful transsphenoidal microadenomectomy and therefore underwent pituitary radiotherapy. In both patients there was progressive normalization of hypothalamo-pituitary-adrenal function and at 8 and 10 years after radiotherapy their Cushing's syndrome remained in remission clinically and biochemically. Most importantly, they have both achieved adult heights within their respective expected ranges with close clinical observation and replacement growth hormone therapy. Thyroid and gonadal function is normal and neither patient requires any other hormone replacement therapy. Pituitary radiotherapy is thus a safe, effective and well tolerated second-line therapy for paediatric Cushing's disease. Collaboration between the paediatric and adult departments and an experienced radiotherapist contributed to the successful outcome of these two patients.

Pituitary tumors: surgical and medical management

The pituitary gland has been termed the 'master gland' because of the myriad of hormones that emanate from it that are vital for normal homeostasis as well as growth and development. Primary tumors of this region are frequent and account for up to 10% of intracranial tumors. Pituitary tumors are monoclonal in origin, and may arise from any of the different cell types of the pituitary gland. Hence, these tumors may be manifest by their hormonal secretions. This may lead to profound and striking physiological changes attributable, for example, to prolactin, growth hormone, or ACTH excess. The central location of the pituitary gland also leads to characteristic compressive symptoms. This review will explore the clinical presentations of growth hormone, ACTH, and prolactin secreting tumors as well as the non-secreting pituitary tumors. Advances in neuroimaging and neuropharmacology have resulted in changes in our treatment of these tumors. Treatment modalities including surgical, medical, and radiation therapy will be addressed. The treatment of choice is dictated by the type of tumor and the nature of the excessive hormonal expression. Outcomes and efficacy of treatment are discussed.

MIB1 immunopositivity is associated with rapid regrowth of pituitary adenomas

Pituitary adenomas are generally regarded as benign tumours, but they may recur. We identified eight patients with pituitary adenomas that showed rapid regrowth within 2 years of initial surgery. We estimated the percentage of cells in each specimen that showed positive immunostaining for MIB1 (a novel anti-Ki-67) and compared the values to those of 40 adenomas that showed no regrowth. The mean MIB1 index for 40 adenomas that showed no evidence of regrowth was 0.19 +/- 0.06%. This was significantly (p < 0.0001) lower than that for adenomas that showed rapid regrowth (1.27 +/- 0.31%), based on the initial resected specimens. Immediately after detection of rapid regrowth and in adenomas that were resistant to bromocriptine or irradiation, the MIB1 index was always greater than 1.0%. Most patients with rapidly regrowing adenomas were well controlled by radiation therapy. Our results suggest that a MIB1 index greater than 1.0% may be a useful predictor of rapid regrowth of pituitary adenomas and may be useful for planning of therapy.

Investigation, management and therapeutic outcome in 12 cases of childhood and adolescent Cushing's syndrome

OBJECTIVE

Cushing's syndrome in childhood and adolescence is rare. We analysed the clinical presentation, investigation, management and therapeutic outcome in 12 paediatric patients with Cushing's syndrome.

DESIGN

Retrospective review of case notes.

PATIENTS

Twelve patients, 7 males and 5 females, aged 7.6-17.8 years with Cushing's syndrome who were admitted to St Bartholomew's Hospital between 1978 and 1993, were studied. Aetiologies of the Cushing's syndrome patients were: Cushing's disease (9), adrenal adenoma (1), nodular adrenocortical dysplasia (1) and ectopic ACTH syndrome (1). One further male patient, aged 17.8 years who presented with Nelson's syndrome after bilateral adrenalectomy for Cushing's disease in 1978, is described.

MEASUREMENTS

Presenting symptoms, endocrine tests for hypercortisolism, imaging studies, simultaneous bilateral inferior petrosal sinus sampling and therapeutic strategies are discussed.

RESULTS

The dominant clinical features were obesity, short stature, virilization, headaches, fatigue and emotional lability. Investigations confirmed Cushing's syndrome by demonstrating absent cortisol circadian rhythm and impaired suppression on low dose dexamethasone test and differentiated Cushing's disease from other aetiologies by high dose dexamethasone and hCRH tests. In Cushing's disease, pituitary CT scan identified a microadenoma in 4 out of 9 subjects. In 5 of the 9 patients (3 with a normal pituitary CT, 2 with a suggested microadenoma), a pituitary MRI scan was performed and confirmed the CT findings. Inferior petrosal sinus catheterization for ACTH in 4 patients confirmed excess pituitary ACTH secretion, correctly lateralizing the tumour in all cases. Cushing's disease was treated by transsphenoidal surgery alone in 6 patients and combined with pituitary irradiation in 3 patients. Of these 9 patients, 7 are cured and 2 are in remission. The patient with Nelson's syndrome is cured after total hypophysectomy.

CONCLUSIONS

This series describes the clinical features, aetiologies and management of juvenile Cushing's syndrome. Investigation with low and high-dose dexamethasone suppression tests and hCRH test identified the aetiology in each case. Collaboration between paediatric and adult endocrine units together with an experienced neurosurgeon and a radiotherapist contributed to the successful therapeutic outcome of these patients.

Prolactinoma in 53 men: clinical characteristics and modes of treatment (male prolactinoma)

The data of 53 men treated for hyperprolactinemia were reviewed retrospectively to determine the efficacy of the medical and surgical treatment. The clinical assessment, radiological and neuro-ophthalmological investigations and hormonal measurements were performed before treatment as well as during the follow-up period. Imaging evaluation included computed tomography and/or nuclear magnetic resonance of the pituitary. The hormonal profile examined was PRL, FSH, LH and testosterone, as well as TSH, T4, T3 and cortisol. Thirty patients were treated solely by dopamine agonists (DA), twenty-two men had pituitary surgery in addition to DA treatment, and one patient was operated with no need for medical treatment. Decreased sexual function was the most frequent presenting symptom (85% of the men). Most of the patients had large invasive macroadenomas, with suprasellar extension. More than 40% had visual field defects. Baseline PRL (mean +/- SE) was 51,842 +/- 9,292 mU/L and decreased to a level below 575 mU/L in 70% of the patients after DA therapy. Mean testosterone, FSH, and LH levels increased slightly but significantly from the low baseline values. Complete clinical response to DA was achieved in 49% of the men and the tumor mass disappeared entirely in 21%, and incompletely in 42%. The surgical success rate (transsphenoidal or trans-cranial operation) was low--only one of the 23 patients operated recovered completely, and most of the patients were left with hormonal deficits and hyperprolactinemia. These findings indicate that continuous medical treatment with DA should be the preferred mode of treatment for male prolactinomas. Removal of these large tumors is recommended only when the tumors are life-threatening or if drug resistance or severe adverse reactions to DA develop.

Endocrine functions in long-term survivors of low-grade supratentorial glioma treated with radiation therapy

Endocrine functions were studied in long-term survivors of low-grade glioma treated with radiotherapy. Hypothalamic-pituitary dysfunction has recently been reported to occur more frequently than generally considered. Because endocrine dysfunction is a treatable condition, careful testing and, if necessary, supplementary treatment may enhance quality of life. Thirteen adult patients treated with radiotherapy because of supratentorial low-grade glioma at least one year before (range 1-11.5 years) were tested. Focal brain radiotherapy (45-61.2 Gy), with calculated dose to the hypothalamic-pituitary area ranging from 0 to 50 Gy (mean 36.1) had been applied to all patients. Serum levels of pituitary hormones, cortisol and thyroid hormone were determined before and after stimulation with hypothalamic hormones. In 10 out of 13 patients one or more hormonal values were out of the normal range. Most disturbances were demonstrated in the pituitary-adrenal axis (8 patients) and the GH-axis (4 patients). None of the patients had clinical symptomatology of adrenal, thyroid or gonadal dysfunction. Careful endocrine testing after cranial radiotherapy may reveal (subclinical) hypothalamic-pituitary dysfunction in long-term survivors. Follow-up testing in these patients seems warranted.

Pituitary tumors. Current concepts in diagnosis and management

Diagnostic advances have resulted in earlier and more frequent recognition of pituitary tumors. Pituitary tumors cause problems owing to the hormones they secrete or the effects of an expanding sellar mass--hypopituitarism, visual field abnormalities, and neurologic deficits. Prolactin-secreting tumors (prolactinomas), which cause amenorrhea, galactorrhea, and hypogonadism, constitute the most common type of primary pituitary tumors, followed by growth hormone-secreting tumors, which cause acromegaly, and corticotropin-secreting tumors, which cause Cushing's syndrome. Hypersecretion of thyroid-stimulating hormone, the gonadotrophins, or alpha-subunits is unusual. Nonfunctional tumors currently represent only 10% of all clinically diagnosed pituitary adenomas, and some of these are alpha-subunit-secreting adenomas. Insights into the pathogenesis and biologic behavior of these usually benign tumors have been gained from genetic studies. We review some of the recent advances and salient features of the diagnosis and management of pituitary tumors, including biochemical and radiologic diagnosis, transsphenoidal surgery, radiation therapy, and medical therapy. Each type of lesion requires a comprehensive but individualized treatment approach, and regardless of the mode of therapy, careful follow-up is essential.

An audit of selected patients with non-functioning pituitary adenoma treated by transsphenoidal surgery without irradiation

OBJECTIVE

To determine whether the rate of tumour regrowth in patients with non-functioning pituitary tumour treated by transsphenoidal surgery and selected for observation without post-operative irradiation is acceptably low, and to identify a group of patients who could appropriately avoid pituitary irradiation.

SUBJECTS

One hundred and thirty-two patients treated by transsphenoidal surgery, of whom 98 did not undergo post-operative irradiation. These 98 were selected as having had apparently complete surgical removal, and as lacking features of tumour invasion or rapid growth; 73 of them are being followed by serial pituitary imaging to detect tumour regrowth.

RESULTS

Forty-two patients who have been imaged on two or more occasions or more than two years after operation have shown no sign of tumour regrowth; 25 of them have been imaged at 3 or more years after operation, 13 at more than 5 years, and 4 at more than 10 years. Eight patients have shown regrowth as judged by imaging, although only one had pressure symptoms at the time; 5 out of 6 of these recurrences were found within 5 years of operation (two cannot be timed). The unirradiated group of 73 patients showed 90% recurrence-free survival at 5 years (95% confidence limits 80-100%).

CONCLUSIONS

Provided that careful surgery and meticulous recall mechanisms for imaging can be ensured, patients so selected may be given the information contained in these results and offered the choice of follow-up by imaging alone, without pre-emptive irradiation. We recommend that they should be imaged 6-8 weeks post-operatively, then at either 6 or 12 months depending on the appearance, and then every 3-5 years for at least 15 years. By this means, many patient-years of good health and relative medical independence can be gained, together with some financial saving.

Evaluation of the effects of radiotherapy on macroprolactinomas using the decline rate of serum prolactin levels as a dynamic parameter

The effect of radiotherapy (24- > 50 Gy) on serum prolactin levels was studied in 28 patients with macroprolactinomas. All had been treated with surgery and 21 had also received bromocriptine interim therapy. Serum prolactin levels decreased in a log-linear fashion with time, both in the patients who never received bromocriptine and those who were treated with this drug. The decline rate of serum prolactin, which thus represented the effect of radiotherapy, was independent of intercurrent bromocriptine therapy, radiation dose and variables such as pre-radiation prolactin levels, tumour grade and tumour extension. During the course of follow-up (3-24 years) serum prolactin normalized in eight patients (28.6%). It is proposed to use the decline rates as a dynamic parameter to predict normalization time and time required for continuance of dopaminergic drug therapy.

Malignant prolactinoma with extracranial metastases: a report of three cases

OBJECTIVE

Prolactin-secreting tumours of the pituitary almost never metastasize extracranially. However, we have recently seen three such patients, whose presentation, clinical course and response to treatment are reviewed in order to determine whether they possess unique clinical features, and to assess optimum therapy.

DESIGN AND PATIENTS

Three patients with extracranial metastases from prolactinomas have been retrospectively reviewed.

MEASUREMENTS

Clinical courses, biochemical parameters and imaging modalities (CT, MR and radiolabelled somatostatin analogue scanning) and histopathology were assessed before and during different therapeutic regimens.

RESULTS

All three patients' presentations were initially unremarkable, but later each had persistent and relentlessly increasing serum prolactin concentrations and evidence of distant spread of their tumours. The first patient presented aged 32 and was treated with repeated transsphenoidal resections of the tumour, pituitary radiotherapy, high dose bromocriptine therapy, the somatostatin analogue octreotide and chemotherapy. Nine years after the original diagnosis a liver biopsy revealed carcinoma cells positively immunostaining for prolactin. At autopsy further microscopically similar metastases were seen in both lungs and the left hilar lymph nodes. The second patient presented aged 48 and was treated with external beam pituitary radiotherapy, bromocriptine, transsphenoidal hypophysectomy and chemotherapy. Fifteen years after the original diagnosis bone biopsy revealed carcinoma cells positively immunostaining for prolactin; the patient developed interstitial nephritis and died in renal failure. The third patient presented aged 48 with hypogonadism and bitemporal hemianopia due to a macroadenoma. This was removed transfrontally and followed by external beam radiotherapy. After recurrence, further surgery and radiotherapy were undertaken, but the tumour continued to grow and the patient died suddenly of a pulmonary embolus. At autopsy, tumour was found in thoracic lymph nodes and lung capillaries.

CONCLUSIONS

These three patients may be added to the previous two reported cases of malignant prolactinoma with extracranial spread. Several different therapies were tried but were of limited value in controlling the progression of the disease, although chemotherapy is an important modality to be considered. No particular factor or combination of factors at presentation differentiated these patients from more typical patients whose disease is much less aggressive.

Delayed radiation necrosis of the central nervous system in patients irradiated for pituitary tumours

Four cases of delayed radiation necrosis involving the CNS were found in a group of 46 patients irradiated for pituitary tumours over a six year period. This occurred in three of 11 patients with Cushing's disease representing an incidence of 27% in this group. There were no cases among 11 patients with acromegaly or among seven with prolactinomas. One case (6%) was found in the 17 patients with chromophobe adenomas. Standard doses of radiation were delivered to these patients and the findings support suggestions that the metabolic disturbances of Cushing's disease may reduce tolerance to radiation. Our results and a literature review indicate that if radiotherapy is used to treat Cushing's disease, the total dose should be less than 50 Gy at 2 Gy per day fractionation.

Clinical management of prolactinomas: a ten-year experience

A ten-year experience on 36 patients bearing macroprolactinomas (MP) and 86 others bearing microprolactinomas (mP) is reported in this study. Different therapeutical approaches were used: 1) trans-sphenoidal surgery in 24 patients with MP and in 25 with mP; 2) medical therapy with the oral form of bromocriptine (BRC) in all the 24 patients with MP previously subjected to surgery, in 48 patients with mP ab initio, and in 16 out of 25 patients with mP previously subjected to surgery; 3) medical therapy with the long-acting injectable forms of BRC in 12 MP- and 13 mP-bearing patients, and 4) conventional radiotherapy in 12 of the 24 patients with MP previously subjected to surgery. The follow-up, performed five years after surgery, showed that: a) all the 24 patients with MP but one had normal PRL levels during BRC administration, with a rebound of hyperprolactinemia in all cases after withdrawal; b) during the treatment BRC caused normalization of PRL in 15 of the 16 mP-bearing patients surgically treated and in all the 48 mP-bearing patients only treated with BRC; c) in 20 of the 25 patients the treatment with injectable retard BRC caused the normalization of plasma PRL and the shrinkage of the tumor mass in all the patients with MP but one, as revealed by seriate CT scans. In conclusion, the surgical treatment of prolactinomas was ineffective to normalize plasma PRL levels in most patients whereas BRC, in standard or in retard forms, was able to normalize plasma PRL levels, reduce the tumoral mass and preserve the pituitary residual tissue. BRC should be, therefore, used as first choice therapy both for MP and mP.

Long-term follow-up of radiotherapy for pituitary adenoma: the absence of late recurrence after greater than or equal to 4500 cGy

Recent literature has suggested that late recurrence of pituitary adenoma after radiotherapy is common. We hypothesized that late failures might be a result of inadequate dose (less than 4500 cGy). To investigate, we analyzed 105 patients treated at our institution between 1965 and 1986 (analysis, 2/89). The minimum observation time was greater than or equal to 5 years in 58% and greater than or equal to 10 years in 30% of the patients. All patients received megavoltage radiotherapy (range, 4200-5500 cGy; mean, 4821 cGy) at a mean dose per fraction of 172 cGy; 100 patients received greater than or equal to 4500 cGy tumor dose. Twenty-nine patients received radiotherapy alone, and 76 had postoperative radiotherapy after frontal craniotomy (20 patients) or transsphenoidal hypophysectomy (56 patients). At presentation, 71% of patients had extrasellar disease, 57% had visual field deficits, and 50% had endocrinopathy. Of patients treated postoperatively, 74% had gross residual disease. Four local failures occurred at 13, 16, 57, and 64 months after postoperative radiotherapy, all within the irradiated volume (tumor doses of 4700, 4715, 5000, and 5100 cGy). All four patients had presented with moderate to extensive extrasellar disease with visual field defects. Two of the four remain free of second recurrence at 7 and 13 years after salvage transsphenoidal hypophysectomy. The local control rate with radiotherapy (product-limit method) at 10 years was 100% in the radiotherapy-alone group and 92% in the postoperative radiotherapy group (95% for all patients). To prevent bias, seven patients who received bromocriptine, none of whom demonstrated a recurrence, were censored from the local control analysis at the initiation of the drug. No patient in this study suffered recurrence greater than 64 months after radiotherapy, with 31 patients (none with bromocriptine) observed 10 to 21 years. We conclude that treatment of pituitary adenoma with greater than or equal to 4500 cGy in 25 fractions can result in a high (greater than or equal to 90%) probability of stable long-term control.

Megavoltage pituitary irradiation in the management of prolactinomas: long-term follow-up

OBJECTIVE To determine the long-term effects of external beam megavoltage radiotherapy (RT: 4500 cGy via three portals at 180 cGy or less total daily dose) on endocrine function in prolactinomas. DESIGN Longitudinal study following radiotherapy with periodic re-assessment at regular intervals, at least 2 months off dopamine agonist therapy. PATIENTS Thirty-six female patients, age range 19-50 years, with either macroprolactinomas (12 patients) or microprolactinomas (24 patients), but without significant suprasellar extensions. MEASUREMENTS Clinical appraisal, and anterior and posterior pituitary assessment: basal levels at yearly intervals or less, with dynamic screening with TRH, LHRH and hypoglycaemic stimulation every 2-3 years. RESULTS Before RT, serum prolactin (PRL) levels ranged from 1150 to 34,000 mU/l; after RT (mean 8.5 years, range 3-14), serum PRL fell to normal (i.e. less than 360 mU/l) in 18 of the 36 patients (50%), and to just above the normal range (378-780 mU/l) in a further 10 (28%). Two patients had PRL levels at their last follow-up higher than those at presentation, with one patient showing evidence of tumour recurrence on CT scan. A total of eight of the 36 patients (23%) developed post-RT gonadal deficiency by the end of follow-up at 8 +/- 3.1 years (+/- SD, range 3-11), but six were aged over 40 years at that time. GH deficiency was frequent, occurring in 94% of patients, usually from 2 to 3 years post-RT, while TSH deficiency and reduced ACTH reserve was uncommon (each 14%), and occurred later. In the subgroup of 12 patients with macroprolactinomas, results were broadly comparable. CONCLUSIONS Megavoltage RT produces a progressive fall in serum prolactin in the great majority of patients with prolactinomas, with a relatively low incidence of TSH or ACTH deficiency. As it is now clear that dopamine agonist therapy alone provides sufficient management for microprolactinomas, RT may be used for the long-term control of macroprolactinomas, together with interim dopamine agonist therapy. It allows pregnancy to be safely undertaken but, in view of the delayed onset of gonadal deficiency, its administration should be timed with respect to the desired onset of conception in women.

Management of prolactinomas

The management of prolactinomas requires a complex interaction of medical, surgical and radiotherapeutic intervention. With the judicious use of all these modalities, patients can usually be managed with great success and, perhaps more importantly, their presenting complaints (gonadal dysfunction and infertility) are usually completely corrected.

Prolactin and related peptides in pregnancy

This brief review has attempted to portray the complex involvement of prolactin in pregnancy. Pituitary prolactin production and lactotroph proliferation are markedly affected by oestrogens and pregnancy. Enlargement of pre-existing prolactinomas may occur during pregnancy induced with dopamine agonist drugs, and this can be a major clinical problem with larger tumours. Prolactin is produced by late luteal and decidualized endometrium as well as by the pituitary gland, but much less is known about its secretory regulation or its function. The family of prolactin-related protein hormones is rapidly expanding with the recognition of placental lactogens, variant growth hormone, proliferin, decidual luteotropin, and at least two further prolactin-related peptides in rodents. This complex system of related but distinct protein hormones, with different temporal patterns of production during gestation, suggests an important physiological role, but it remains to be seen to what extent they are involved in placental function itself, maternal metabolism or fetal growth.

Radiation and hypothalamic-pituitary function

In adults, hypopituitarism is a common consequence of external radiotherapy. The clinical manifestations may be subtle and develop insidiously many years after radiotherapy. Anterior pituitary deficiencies can therefore only be detected by regular testing, including dynamic tests of GH and ACTH reserve. Although the deficiencies most commonly develop in the order GH, gonadotrophins, ACTH then TSH, this sequence may not be predictable in an individual patient and comprehensive testing is therefore required. The tests should ideally be performed annually for at least 10 years after treatment or until deficiency has been detected and treated. It is not only the patients with pituitary disease who are at risk of developing hypopituitarism after radiotherapy. Any patient who receives a total dose of irradiation of 20 Gy or more to the hypothalamic-pituitary axis is at risk of hypopituitarism, although the threshold dose may be lower than this. This is particularly important in the long-term survivors of malignant disease in whom endocrine morbidity may be relatively common and in whom this can be easily treated, with consequent improvement in quality of life. Whilst patients who receive a high total dose of irradiation are at increased risk of developing multiple deficiencies, a higher fraction size also increases the risk of anterior pituitary failure. There is good evidence that the earliest damage to the hypothalamic-pituitary axis after external radiotherapy is at the level of the hypothalamus. However, patients who undergo pituitary ablation with interstitial radiotherapy or heavy particle beams are likely to sustain direct damage to the pituitary. In these patients, the sequence in which individual pituitary hormone deficiencies develop is generally the same as that observed with the hypothalamic damage after conventional external radiotherapy. The increasing use of radiotherapy as a means of treatment for malignant disease means that new groups of patients with potential for endocrine dysfunction are emerging. Whole body irradiation in the preparation for bone marrow transplant is one such treatment and although hypothalamic-pituitary damage appears to be confined to GH deficiency in children, longitudinal experience is limited to date, particularly in adults. The treatment of malignant disease in childhood is of particular importance in terms of the delayed endocrine sequelae. The hypothalamic-pituitary axis may not be the only endocrine tissue damaged by treatment in these patients and management is therefore more complicated. In the growing child, the potential association of growth hormone deficiency, gonadal failure or premature puberty and thyroid dysfunction mean that expert endocrine supervision is essential for optimum long-term outcome.

Radiation-induced hypopituitarism is dose-dependent

Radiation-induced hypopituitarism has been studied prospectively for up to 12 years in 251 adult patients treated for pituitary disease with external radiotherapy, ranging in dose from 20 Gy in eight fractions over 11 days to 45 Gy in 15 fractions over 21 days. Ten further patients were studied 2-4 years after whole-body irradiation for haematological malignancies using 12 Gy in six fractions over 3 days and seven patients were studied 3-11 years after whole-brain radiotherapy for a primary brain tumour (30 Gy, eight fractions, 11 days). Five years after treatment, patients who received 20 Gy had an incidence of TSH deficiency of 9% and in patients treated with 35-37 Gy, 40 Gy and 42-45 Gy, the incidence of TSH deficiency (22, 35 and 52% respectively) increased significantly (P less than 0.001) with increasing dose. A similar relationship was observed for both ACTH and gonadotrophin deficiencies when the 20 Gy group was compared to patients treated with 35-45 Gy (P less than 0.01 and P less than 0.05 respectively). Growth hormone deficiency was universal by 5 years over the dose range 35-45 Gy. In seven patients who were treated with 30 Gy in eight fractions over 11 days, deficiencies were observed at a similar frequency to the 40 Gy group (15 fractions, 21 days). No evidence of pituitary dysfunction was detected in the ten patients who received 12 Gy (six fractions, 3 days). Both total radiation dose and fractionation schedule may determine the incidence of pituitary hormone deficiencies. The dose below which deficiencies do not occur is probably irrelevant to therapeutic irradiation of pituitary and other intracranial neoplasms.

Pituitary adenoma: the efficacy of radiotherapy as the sole treatment

The management of patients with pituitary adenomas by radiotherapy alone, using modern techniques of evaluation and current standards of treatment, has not been examined. This is a retrospective review of 29 such patients with nonfunctional or prolactin secreting pituitary macroadenomas. Patients were analyzed by visual fields, hormone levels, and CT scans. All but one patient received a tumor dose of 4500 cGy in 4 to 5 weeks. The tumor was controlled in 26 of 28 (93%) patients for an observed period of 3 to 14 years. Seventeen of 21 (81%) patients with visual impairment experienced normalization or improvement, and seven of ten (70%) patients with hyperprolactinemia achieved normalization of their serum prolactin levels. Post-treatment CT scanning revealed persistent tumor in nine of 17 patients despite clinical improvement. We conclude that: (a) radiotherapy is an effective treatment for these tumors; (b) doses need not exceed 4500 cGy in 25 fractions; (c) radiation is effective for improving vision; (d) radiation can normalize hyperprolactinemia; and (e) tumor regression is variable and unrelated to observed symptom regression.

Massive prolactinoma with galactorrhoea in a prepubertal boy

An 8 year old prepubertal boy presented with raised intracranial pressure, left proptosis and was noted to have galactorrhoea. Cranial computerized tomography revealed a large pituitary tumour infiltrating the cavernous sinus and left orbit. The serum prolactin was 180,600 mU/l (normal value less than 360 mU/l). Prolactinomas are rare in children and galactorrhoea has not previously been reported in a prepubertal child. The management of massive prolactinomas is difficult, but the child presented has made an impressive response to a combination of treatment with surgery, dopamine agonist therapy and radiotherapy.

Long-term effects of megavoltage radiotherapy in acromegaly

The progress of 41 Chinese patients with acromegaly treated with megavoltage radiotherapy was reviewed after a mean follow-up of 4.5 (one-ten) years. Nine received prior surgery. Radiotherapy was delivered by a 3-field technique to a total of 4000-5000 cGy in 25 fractions. By life table analysis successful treatment of growth hormone (GH) hypersecretion, as defined by a mean GH concentration of less than or equal to 10 mu/L, could be expected in 6, 11, 26, 64 and 67% of the patients after one, two, five, eight and ten years respectively. Median intervals before achieving a mean GH level of less than or equal to 10 mu/L were 6.6 and 8.6 years following radiotherapy with the higher (4500-5000 cGy) and lower (4000 cGy) doses respectively, suggesting a tendency towards earlier response following radiotherapy with the higher dose. The prevalence of acquired hypopituitarism in patients followed up for over five years was 40% for gonadotrophins, 30% for TSH and 20% for ACTH deficiency respectively. In the majority of patients, acquired hypopituitarism was not apparent within five years after radiotherapy. No mortality or major side effects were noted following radiotherapy. In 34 patients on long-term bromocriptine treatment, mean GH concentrations were normalised in 26.5% of patients. We conclude that with judicious selection of patients and use of adjunctive medical therapy, megavoltage radiotherapy remains a safe and satisfactory form of treatment for acromegaly especially if expert transphenoidal surgery is not readily available.

Treatment of CNS tumours with conventional radiotherapy: the importance of dose & volume factors in tumour control & CNS radiation tolerance

Improved localisation of central nervous system (CNS) tumours resulting from newer diagnostic imaging techniques may allow the therapeutic irradiation of smaller volumes than currently practiced with the possibility of less normal tissue injury and/or the use of higher radiation doses. The influence of radiation dose and volume on the control rates for various types of CNS tumour and on the radiation tolerance of CNS tissue is imperfectly understood. Available data on these fundamental issues in the radiation treatment of CNS tumours is reviewed.

Prolactinomas presenting as primary amenorrhoea and delayed or arrested puberty: response to medical therapy

Fourteen patients presented with arrested pubertal development associated with prolactin-secreting pituitary tumours; serum prolactin ranged from 4000-104,300 mU/l in the ten females and 920-68,000 in four males. Skull X-ray showed a markedly expanded pituitary fossa in eight patients. CT scan and/or air encephalography showed macroadenomas in nine, of whom seven had large suprasellar extensions to their tumours, yet only five had complained of headache and only two had visual field defects. All were treated with bromocriptine (7.5-60 mg/day) which lowered prolactin substantially in all and into the normal range in 11 (range less than 60-3090, median 105 mU/l). Puberty thereafter progressed spontaneously in 13, but in one patient, whose prolactin did not suppress completely, menarche could be induced only with clomiphene. Anterior pituitary function improved on bromocriptine. In seven patients with macroadenomas, tumour shrinkage into the pituitary fossa was complete and in two others incomplete shrinkage was followed by transsphenoidal hypophysectomy. Seven patients received pituitary irradiation, six after bromocriptine-induced shrinkage and one after transsphenoidal surgery. At follow-up 6 months to 10 years (median 5 years) after presentation, ten remain on bromocriptine with a suppressed serum prolactin, one has a normal prolactin after surgery, and three are off bromocriptine with residual hyperprolactinaemia (418-4680 mU/l). To date, four females have become pregnant and one male has fathered two children. Prolactinomas are an important, albeit rare, cause of arrested puberty and should therefore be sought. Most patients respond well to bromocriptine, with or without pituitary irradiation.

Prognostic factors and results of radiotherapy alone in the management of pituitary adenomas

Prognostic factors and results of therapy were analyzed in a retrospective review of 70 patients with pituitary adenomas treated with radiotherapy alone from January 1954 through December 1982 at the Radiation Oncology Center, Mallinckrodt Institute of Radiology. The 10-year overall and disease-free survival was 77.8 and 76.0%. The expected survival for an age-, sex-, and race-matched population was not significantly greater at 87.2%. The 10-year disease-free survival for the distinct tumor types was 100% for Cushing's disease, 82.3% for patients with amenorrhea/galactorrhea, 79.6% for non-functioning adenomas, 69.0% for acromegaly, and 66.7% for Nelson's syndrome. Prognostic variables analyzed were age, race, sex, tumor type, tumor extent, visual field defects at diagnosis, and volume irradiated. Only the presence of visual field defects at diagnosis conferred a poor prognosis (p less than 0.001). There was a tendency toward superior tumor control with radiation doses greater than 4500 cGy (p = 0.15). The median time to progression of disease was 4.2 years, with the last failure occurring at 12 years following the completion of radiotherapy. Severe complications were apparent in 5 patients (7.1%), including one death from central nervous system radionecrosis.

The management of pituitary tumours and post-operative visual deterioration

The indications and results of transsphenoidal surgery for pituitary adenomas are analysed. The advantages and disadvantages of Bromocriptine and radiotherapy are considered. Transsphenoidal surgery does not damage pre-existing pituitary function. It produces excellent results in micro and mesoadenomas, curing about 70-80% of patients irrespective whether the tumour produces ACTH, prolactin or growth hormone. Moreover there is a very small relapse rate. Macroadenomas of non-functioning type are also well treated by transphenoidal surgery, with a small recurrence rate as judged by CT scan follow-up. But macroadenomas secreting prolactin or growth hormone are less effectively treated by transsphenoidal surgery, only about 40% being cured. Invasive macro prolactinomas are not helped by surgery and should be treated with Bromocriptine and radiotherapy. Radiotherapy should be used sparingly and has inevitable complications. Post-operative delayed visual deterioration is caused either by recurrent tumour or radiotherapy. There is no good evidence to support the secondary empty sella syndrome as a cause of such delayed visual deterioration.

Therapeutic applications of bromocriptine in endocrine and neurological diseases

Bromocriptine, or 2-bromo-alpha-ergocryptine, is a semisynthetic ergot alkaloid. The basis of its therapeutic application in endocrine and neurological diseases is its action as a potent dopamine agonist. Its ability to inhibit prolactin secretion has led to its successful use in suppression of puerperal lactation and in the treatment of pathological hyperprolactinaemia causing galactorrhoea, infertility or hypogonadism. It has been shown to be safe in pregnancy. The ability of bromocriptine to reduce the size of large prolactin-secreting pituitary tumours has resulted in the recovery of pituitary function and correction of visual field defects. Bromocriptine is less effective in acromegaly but is useful as adjuvant therapy to radiotherapy and/or surgery which has been the standard mode of treatment. It has been shown to be efficacious either alone or in combination with levodopa in the treatment of Parkinson's disease. Therapy with low doses appears to be effective and is associated with a significantly reduced incidence of side effects. The successful use of bromocriptine has also been reported for the treatment of non-functioning pituitary tumours, premenstrual syndrome, cyclical mastalgia, luteal phase insufficiency and portal-systemic encephalopathy, although its role in the treatment of these latter disorders remains uncertain until more extensive and adequately controlled trials have been conducted.

Long-term treatment of hyperprolactinaemia with bromocriptine: effect of drug withdrawal

Fifty-one patients with hyperprolactinaemia (23 with macroadenoma, 23 with microadenoma, and five with idiopathic hyperprolactinaemia) were treated with bromocriptine for 2-12 years (4.9 +/- 2.9 years, mean +/- SD). During therapy, the serum PRL levels were suppressed into the normal range in all but five patients. In these five patients, despite the high circulating PRL, gonadal function returned to normal in three, while in the other two gonadotrophin reserve was impaired even before therapy. Gel chromatography showed that one of these patients had a high proportion of a large molecular weight form of PRL. Twenty-four patients received bromocriptine as the sole method of treatment for over 2 years (3.4 +/- 2.3 years). In five out of the 24 subjects (21%), serum PRL remained normal with no clinical symptoms after prolonged drug withdrawal (1-4 years). Twenty-one patients received radiotherapy in conjunction with bromocriptine therapy. Of these 11 had prior surgery. After a follow-up of 6.0 +/- 3.0 years after radiotherapy, serum PRL remained within the normal range in 6 out of 21 subjects (29%), 1-4 years after bromocriptine withdrawal. One of the patients had impaired GH response to insulin hypoglycaemia developing after radiotherapy. We conclude that prolonged bromocriptine treatment is an effective treatment for prolactinomas.

Symptomatic hypothalamic-pituitary dysfunction in nasopharyngeal carcinoma patients following radiation therapy: a retrospective study

Endocrine assessment was performed in 32 relapse-free southern Chinese patients (21 males and 11 females, aged 27-50 years at the time of assessment) 5-17 years following radiation therapy (RT) alone for early nasopharyngeal carcinoma (NPC). Initial screening was done using questionnaires emphasizing on impaired sexual function and menstrual disturbance plus measurement of serum levels of thyroxine, free thyroxine index, thyrotropic hormone, prolactin, and additionally testosterone for males only. Those showing abnormalities were subjected to detailed pituitary function tests. Hypothalamic-pituitary dysfunction was found in 7 female patients and only 1 male patient. A delayed TSH response to thyrotropin releasing hormone suggesting a hypothalamic disorder was seen in 6 of the affected female patients, and hyperprolactinaemia in also 6. None of the patients had evidence of diabetes insipidus. Hypopituitarism became symptomatic 2-5 years after RT with a mean latent interval of 3.8 years. A practical protocol for regular endocrine assessment for NPC patients after RT has been proposed. Multiple linear regression analysis of the radiotherapeutic data from the 11 female patients indicates that the likelihood of late occurrence of symptomatic hypothalamic-pituitary dysfunction following RT is dependent on the TDF of the target dose to the nasopharyngeal region and the height of the upper margin of the opposed lateral facial fields above the diaphragma sellae (coefficient of multiple correlation = 0.9025). Except when the sphenoid sinus or the middle cranial fossa is involved, it is advisable to set the height of the upper margin of the lateral facial field at a level no higher than the diaphragma sellae. The hypothalamus and possibly the pituitary stalk as well may sustain permanent damage by doses of radiation within the conventional radiotherapeutic range for carcinomas.

Primary radiotherapy of prolactinomas. Eight- to 15-year follow-up

Eight women with amenorrhea, galactorrhea, and hyperprolactinemia, of whom six had macroadenomas and two had microadenomas, were treated with conventional (cobalt-60) external radiotherapy, and their progress was monitored for eight to 15 years. Normoprolactinemia was established in five of these patients after two to 13 years (median, nine years). A recurrence was treated surgically in one patient, and stable prolactin values and roentgenographic features have been maintained in two patients. Hypopituitarism has developed in only one patient to date, and no other complications of radiotherapy have been observed. These findings, together with the few previous reports on the long-term effects of radiotherapy on macroprolactinomas, have been compared with the long-term results following surgery or dopamine agonist therapy. The normalization of prolactin values is considerably delayed following radiotherapy compared with the other two therapeutic modalities. However, radiotherapy affords permanent normalization without recurrence in a larger percentage of patients than does surgery and avoids the considerable ongoing cost and inconvenience of daily drug ingestion. The long-term development of hypopituitarism appears to be an acceptably small risk of radiotherapy. Thus, conventional radiotherapy is an attractive treatment option, particularly for macroprolactinomas; adjunctive bromocriptine can be used while awaiting the longer-term benefits of radiotherapy.

Normal growth and pubertal development during bromocriptine treatment for a prolactin-secreting pituitary macroadenoma

An 11-year-old male presented with a 2-year history of headache and lethargy. Serum PRL was elevated at 14,000 mU/l and computerized tomography showed a pituitary macroadenoma. Visual fields and fundi were normal and the testes showed early pubertal changes. There was normal responsiveness of serum cortisol but absence of GH response to hypoglycaemia. After bromocriptine therapy for 4 months serum PRL had fallen to 90 mU/l and the tumour was not visible on repeat computerized tomography. After 7 months treatment, repeat pituitary function testing showed restoration of GH response to hypoglycaemia. Treatment with bromocriptine was continued and there was spontaneous progression of normal puberty; the serum testosterone continued to rise, and height maintained the 50th centile. Bromocriptine therapy should be considered as initial therapy in the management of prolactinomas in prepubertal patients.