Radiation therapy in the multimodal treatment approach of pituitary adenoma. Becker. Strahlenther Onkol. 2002 Apr;178(4):173-86. Radiooncologic University Clinic, Tubingen, Germany. Radioonkologie@KaE.de

BACKGROUND: Pituitary tumors are relatively uncommon, comprising 10-12% of all intracranial tumors. The treatment consisting of surgery, radiotherapy and drug therapy or a combination of these modalities is aimed at the control of tumor cell proliferation and--in endocrine active tumors--the reduction of hormone secretion. However, the slow proliferation characteristics of pituitary tumors necessitate long-term studies for the evaluation of the treatment results. In the last decade there has been continuous improvement in surgical procedures, radiotherapy techniques and drug generation. In this paper, literature will be reviewed to assess the role of modern radiotherapy and radiosurgery in the management of pituitary adenomas. MATERIAL AND METHODS: Nowadays, magnetic resonance imaging for the definition of the target volume and a real three-dimensional (3-D) treatment planning with field conformation and the possibility for non-coplanar irradiation has to be recommended. Most groups irradiate these benign tumors with single doses of 1.8-2.0 Gy up to a total dose of 45 Gy or 50.4 Gy in extensive parasellar adenomas. Adenomas are mostly small, well circumscribed lesions, and have, therefore, attracted the use of stereotactically guided high-precision irradiation techniques which allow extreme focussing and provide steep dose gradients with selective treatment of the target and optimal protection of the surrounding brain tissue. RESULTS: Radiation therapy controls tumor growth in 80-98% of patients with non-secreting adenomas and 67-89% for endocrine active tumors. Reviewing the recent literature including endocrine active and non-secreting adenomas, irradiated postoperatively or in case of recurrence the 5-, 10- and 15-year local control rates amount 92%, 89% and 79%. In cases of microprolactinoma primary therapy consists of dopamine agonists. Irradiation should be preferred in patients with macroprolactinomas, when drug therapy and/or surgery failed or for patients medically unsuitable for surgery. Reduction and control of prolactin secretion can be achieved in 44-70% of patients. After radiotherapy in acromegaly patients somatomedin-C and growth hormone concentrations decrease to normal levels in 70-90%, with a decrease rate of 10-30% per year. Hypercortisolism is controlled in 50-83% of adults and 80% of children with Cushing's disease, generally in less than 9 months. Hypopituitarism is the most common side effect of pituitary irradiation with an incidence of 13-56%. Long-term overall risk for brain necrosis in a total of 1,388 analyzed patients was estimated to be 0.2%. Other side effects are rare too, and do also depend on the damage produced by tumor itself or preceding surgery. They include deterioration of vision in 1.7% of all cases, vascular changes in 6.3%, neuropsychological disorders such as dementia in 0.7% and secondary malignancies in 0.8%, if single doses of 2.0 Gy and total doses of 50 Gy are not exceeded. CONCLUSION: Conventional radiation therapy of pituitary adenoma is highly effective. It is recommended after subtotal resection of primary tumors such as macroadenomas, after gross total resection from endocrine active adenomas with postsurgical hormone secretion and for recurrent tumors. Radiosurgery seems to be a possible treatment alternative in experienced centers, and only in patients with adenomas smaller than 25-30 mm with a minimum distance of 2-3 mm to the chiasm.

J Neurosurg 1998 Dec;89(6):933-8

Radiotherapy for nonfunctional pituitary adenoma: analysis of long-term tumor control.

Breen P, Flickinger JC, Kondziolka D, Martinez AJ

Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pennsylvania, USA.

In this retrospective study, the authors evaluated 120 patients who received radiotherapy for nonfunctional pituitary adenomas between 1960 and 1991.  Radiation doses varied between 37.6 and 65.6 Gy (median 46.7 Gy). Tumors progressed in 15 of the 120 patients by 1 to 25 years after radiotherapy. Actuarial tumor control rates at 10, 20, and 30 years were 87.5+/-3.6%, 77.6+/-6.3%, and 64.7+/-12.9%, respectively. Tumor progression after radiotherapy occurred significantly more often (p=0.0397) in patients with oncocytoma than in patients with nononcocytic null cell adenoma. No other factors correlated significantly with tumor control. One case of optic and oculomotor neuropathy developed 4.5 years after a maximum dose of 50 Gy in 25 fractions. Radiation-induced neoplasms (meningioma and glioblastoma multiforme) developed at a rate of 2.7% at 10 and 30 years. CONCLUSIONS: The oncocytic variant of null cell pituitary adenoma appears less sensitive to control by radiotherapy than nononcocytic undifferentiated cell adenoma. A follow-up period extending beyond 20 years is needed adequately to assess the efficacy of radiotherapy for tumor control. Doses of 40 or 45 Gy in 20 or 25 fractions, respectively, appear optimal.

Int J Radiat Oncol Biol Phys 1991 Aug;21(3):607-14

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

McCollough WM, Marcus RB Jr, Rhoton AL Jr, Ballinger WE, Million RR

Dept. of Radiation Oncology, University of Florida College of Medicine, Gainesville.

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.

Int J Radiat Oncol Biol Phys 1994 Oct 15;30(3):557-65

Radiation therapy for pituitary adenoma: treatment outcome and prognostic factors.

Tsang RW, Brierley JD, Panzarella T, Gospodarowicz MK, Sutcliffe SB, Simpson WJ

Department of Radiation Oncology, Princess Margaret Hospital, Toronto, Ontario, Canada.

PURPOSE: Radiation therapy is often an integral part of postoperative treatment in patients with nonfunctional pituitary adenomas. The Princess Margaret Hospital (PMH) experience was reviewed and analyzed to establish the role of radiation therapy in local control relative to its complications, and to see if subgroups of patients with a greater or lesser risk of recurrence postsurgery can be defined. METHODS AND MATERIALS: Records of 160 patients with nonfunctional pituitary adenoma treated between 1972 and 1986 were reviewed retrospectively. The review focused on 128 patients treated with surgery and postoperative radiation as initial therapy. The median total dose was 45 Gy.  With a median follow-up duration of 8.3 years, the 10-year actuarial local control rate was 87% for the entire 160 patients and 91% for the 128 patients given postoperative radiation as initial treatment. For the 29 patients referred for treatment of recurrent tumor, the 10-year local control rate was 78%. The major complication, hypopituitarism requiring hormonal replacement with thyroxine, glucocorticoid, and sex hormone was observed to date in 65% (100 out of 155), 68% (105 out of 154), and 67% (85 out of 127) of evaluable patients, respectively. Radiation was the contributing cause of the hypopituitarism in only 23%, 16%, and 13%, respectively. There were no cases of brain necrosis or radiation damage to the optic pathways. Two patients developed a fatal in-field glioma of the brain stem at 10 and 15 years following radiation. CONCLUSION: Postoperative external beam radiation therapy is highly effective in preventing recurrence of hormonally inactive pituitary adenomas. Hypopituitarism is commonly observed, but radiation can only be incriminated as the contributing cause in approximately one-fifth of the cases. Treatment of patients at the time of recurrence gave comparable local control rates to those irradiated initially. Favorable patients (age < or = 50, with small tumors removed totally) probably can be safely observed postoperatively with radiation reserved for recurrence.

Radiother Oncol 1996 Oct;41(1):45-53

Role of radiation therapy in clinical hormonally-active pituitary adenomas.

Tsang RW, Brierley JD, Panzarella T, Gospodarowicz MK, Sutcliffe SB, Simpson WJ

Department of Radiation Oncology, University of Toronto, Princess Margaret Hospital/Ontario Cancer Institute, Canada.

BACKGROUND AND PURPOSE: The outcome following radiation therapy (RT) of hormonally-active pituitary adenomas was assessed. The purpose of this analysis was to determine the control rate after radiation, identify any prognostic factors and evaluate the late toxicity. MATERIALS AND METHODS: From 1972 to 1986, 145 patients received RT for hormonally-active pituitary adenomas. The median age was 39 years (range 15-76), with 81 males and 64 females. There were 52 patients with acromegaly, 64 with prolactinoma, and 29 with Cushing's disease. The median follow-up was 7.3 years. RT was given as primary treatment in 17 patients, after initial surgery in 65 patients, and as part of salvage therapy in 63 patients. The median total dose was 50 Gy (daily fraction: 2 Gy). Tumor control was defined as normalization of basal hormonal level and lack of progression of adenoma assessed by imaging studies. The following factors were analyzed for prognostic significance in tumor control: age, sex, tumor type, direction of tumor extension, radiation dose, and radiation field size. RESULTS: The 10-year actuarial proportion of patients with persistent elevated hormone level were 61% following RT alone, and 44% with the addition of medical management. The progression-free rate was 96% at 10 years. Of the 20 deaths, three patients died with uncontrolled pituitary adenoma and three died of treatment complications. The actuarial 10-year overall and cause-specific survival rates were 86% and 97%. The actuarial rates of radiation-induced hypopituitarism were 35%, 22% and 22% at 10 years for thyroid, glucocorticoid and gonadal functions, respectively. None of the factors examined were found to be significant predictors of tumor control. CONCLUSIONS: Post-operative external beam RT is highly effective in preventing recurrence of space-occupying effects of hormonally-active pituitary adenomas. However, long-term biochemical remission is observed only in approximately 40% of patients (at 10 years), with an additional 20% requiring medical therapy. Malignancies of the CNS can develop as an infrequent late event.

Am J Clin Oncol 1992 Dec;15(6):467-73

Radiation therapy in the treatment of pituitary adenomas.

Salinger DJ, Brady LW, Miyamoto CT

Department of Radiation Oncology, Johns Hopkins University, Chambersburg Cancer Treatment Center, Pennsylvania.

Seventy-eight patients with pituitary adenomas were seen in the Department of Radiation Oncology at Hahnemann University between 1961 and 1986. Most were treated with megavoltage photons with or without prior surgery. In this group, 68 patients were followed: 39 were treated with radiation therapy (RT) alone, and 29 were treated with a combination of surgery and RT (S/RT). Patients were followed for 2 to 20 years. Of 68 patients, (97%) experienced complete response to treatment; 86% of the RT patients remained free of disease at 5 and 10 years. In the S/RT group, 100% and 94% remained free of disease at 5 and 10 years, respectively. Total disease-free survivals at 5 and 10 years were, respectively, 91% and 89%. The majority of the failures occurring in the RT group were with growth hormone-secreting tumors and Cushing's disease. Of the 7 patients that failed or recurred (time to recurrence: 1-16 years posttreatment), 6 have been followed: 4 were treated with surgery, 1 with RT, and 1 with S/RT. All 6 have remained free of disease since salvage, with 2- to 14-year follow-up periods. Serious morbidity and mortality have been reported previously with bitemporal field radiation using kilovoltage and low megavoltage RT. However, there was no temporal lobe necrosis or death in any of the patients in this study.

Int J Radiat Oncol Biol Phys 2000 Jul 15;47(5):1337-45

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

Sasaki R, Murakami M, Okamoto Y, Kono K, Yoden E, Nakajima T, Nabeshima S, Kuroda Y

Department of Radiology, Tenri Hospital, Nara, Japan. rsasaki@med.kobe-u.ac.jp

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.

Am J Clin Oncol 1991 Feb;14(1):25-9

Radiation therapy of pituitary tumors: results in 95 cases.

Tran LM, Blount L, Horton D, Sadeghi A, Parker RG

Radiation Therapy Service, VA Medical Center, West Los Angeles, CA 90073.

Between 1967 and 1985 95 patients with pituitary adenoma received radiation therapy at the University of California, Los Angeles (UCLA), and the West Los Angeles Veterans' Administration (VA) Medical Center. Seventy of these patients received radiation therapy immediately as adjuvant therapy following incomplete resection, and 25 were irradiated as primary treatment or after surgical failure. The majority of cases (87%) presented clinically with macroadenomas. Two-thirds of the patients were treated with parallel opposed lateral portals to a midline total dose of 50 Gy. The mean follow-up was 7 years (range: 30-250 months). In our series, there is a difference in response by disease subtype. The control rates were 83% (30 of 36) for nonfunctioning adenoma, 60% (nine of 15) for growth-hormone secreting adenoma, 44% (16 of 36) for prolactin secreting adenoma, three of five for Nelson's syndrome, and three of three for Cushing's disease. There was a tendency for a better response rate with a total dose of greater than or equal to 50 Gy for prolactinoma. None of the patients were known to develop brain necrosis or radiation-induced sarcoma. An analysis of these results and a review of the literature is presented here.

Neurosurgery 1998 Sep;43(3):432-8; discussion 438-9

Reassessment of the role of radiation therapy in the treatment of endocrine-inactive pituitary macroadenomas.

Lillehei KO, Kirschman DL, Kleinschmidt-DeMasters BK, Ridgway EC

Department of Surgery, University of Colorado Health Sciences Center, Denver 80262, USA.

OBJECTIVE: This prospective clinical trial was undertaken to assess the rate of tumor recurrence in patients with endocrine-inactive pituitary macroadenomas who underwent gross total surgical resection of their tumors and did not receive adjuvant radiotherapy. METHODS: Between December 1987 and July 1994, 45 patients with endocrine-inactive pituitary macroadenomas underwent transsphenoidal surgery. In 38 (84%) of these patients, gross total surgical resection was achieved and was confirmed by postoperative magnetic resonance imaging (n = 37) or computed tomography (n = 1). After receiving counseling from the neurosurgeon concerning the risks and benefits of radiation therapy, 32 of the 38 patients elected not to receive adjuvant radiotherapy. Patients were followed through March 1998 with radiographic imaging obtained every 6 months for the first 2 years, annually for postoperative Years 3 and 4, and then every 2 to 3 years thereafter. The study end point was defined as radiographic tumor recurrence or patient death. RESULTS: The mean follow-up duration for the study group was 5.5 years. During that time, 2 of 32 (6%) patients developed recurrence, at 18 and 24 months, respectively, after initial surgery. Both were successfully treated using radiation therapy, with one requiring additional surgery. Three additional patients died as a result of unrelated causes 9, 12, and 49 months, respectively, after initial surgery. Immunocytochemical analysis revealed 66% of the tumors to be weak gonadotroph cell adenomas, 22% to be null cell adenomas, 9% to be silent prolactinomas, and 3% to be silent corticotroph cell adenomas. CONCLUSION: This study demonstrates a 6% 5-year recurrence rate in patients with endocrine-inactive pituitary macroadenomas treated using gross total surgical resection alone. Reserving radiation therapy for the infrequent patient with recurrence and sparing the majority of patients the associated risks inherent in its use seems reasonable.

Int J Radiat Oncol Biol Phys 1997 Mar 15;37(5):1031-4

Symptom resolution, tumor control, and side effects following postoperative radiotherapy for pituitary macroadenomas.

Rush S, Cooper PR

Long Island Radiation Therapy, Manhasset, NY 11030, USA.

This study reports the outcome of 70 patients who were treated by a consistent treatment plan of surgery and postoperative radiotherapy (RT) for pituitary macroadenomas in the modern era [computed tomographic scan or magnetic resonance imaging (MRI), dopamine agonist therapy (DA) added as indicated, and immunohistochemical staining]. Sixty-two patients underwent transsphenoidal surgery (vs. transcranial surgery) and 61 received 45-Gy/25 fractions postoperatively (vs. other dose fractionation schemes). Twenty-four patients received DA for prolactin-secreting tumors. With a median follow-up of 8 years (range 2-15), 68 patients have experienced continuous control of their tumors. Most symptoms related to mass effect abated, while physiologic symptoms such as amenorrhea from markedly elevated prolactin levels tended to persist. Treatment-induced hypopituitarism occurred in 42% of the patients at risk. No patients in this series have died as a result of their pituitary tumor. No gross neuropsychologic dysfunction after treatment has been noted. While it is possible at this time with serial MRI to withhold postoperative RT and observe some patients who have had a "gross total" resection of a macroadenoma, the therapeutic ratio for surgery and adjuvant radiotherapy for patients with nonfunctional tumors as well as select patients with secretory macroadenomas is favorable.

Radiology 1993 Sep;188(3):759-63

Treatment of secretory pituitary adenoma with radiation therapy.

Clarke SD, Woo SY, Butler EB, Dennis WS, Lu H, Carpenter LS, Chiu JK, Thornby JI, Baskin DS

Department of Radiology, Baylor College of Medicine, Houston, TX 77030.

A retrospective review of 44 patients with secretory pituitary adenoma treated with radiation therapy (median total dose of 4,500 cGy with a median fraction size of 225 cGy) was performed to analyze response rates and possible variables associated with failure to respond and with complications. The treatment technique used for 75% of the patients was a combination field; an opposed-lateral fields technique was used for the remainder. Median follow-up was 78.5 months, with 59% followed up for more than 60 months and 34% for more than 120 months. Overall survival was 90%, and disease-free survival was 62%. Response rates were 86% for the group with prolactinoma, 67% for the group with acromegaly, and 50% for the group with Cushing disease; the overall response rate was 71%. Findings of suprasellar extension and those from treatment with opposed-lateral fields correlated significantly with failure to respond. A higher percentage of patients with invasive macroadenomas also failed to respond. More complications were found in patients treated with opposed-lateral fields, but the numbers were too small to reach significance. Radiation therapy remains an important adjunct for the treatment of many patients with secretory pituitary adenoma.

Radiology 1990 Oct;177(1):273-5

Recurrent pituitary adenomas after surgical resection: the role of radiation therapy.

Kovalic JJ, Grigsby PW, Fineberg BB

Radiation Oncology Center, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO 63110.

Postoperative radiation therapy for pituitary adenomas is usually reserved for extensive lesions or those that are incompletely resected. Nineteen patients who received external beam radiation as a salvage procedure after recurrence following surgery alone for pituitary adenomas were studied. At recurrence, nine patients underwent reexcision. All 19 patients underwent external beam irradiation for salvage. Within a median follow-up time of 11.8 years from the time of surgical failure, two patients have died of progressive adenoma, two are alive with disease progression, eight are alive without disease progression, and seven have died of intercurrent disease. The 5-, 10-, 15-, and 20-year overall actuarial (and progression-free) survival rates were 79% (90%), 62% (90%), 44% (80%), and 44% (53%), respectively. Dose of radiation, suprasellar extension at the time of surgical failure, and histologic findings had no bearing on prognosis. One patient developed a radiation-induced brain necrosis that was successfully resected. Radiation therapy can be an effective salvage modality for recurrent pituitary adenomas after surgical failure.

Acta Oncol 1998;37(1):97-9

Radiation therapy alone for growth hormone-producing pituitary adenomas.

Plataniotis GA, Kouvaris JR, Vlahos L, Papavasiliou C

Department of Radiology, University of Athens, Greece.

We present our experience in the treatment of growth hormone (GH)-producing pituitary adenomas using irradiation alone. Between 1983 and 1991, 21 patients suffering from GH-secreting pituitary adenomas were treated with radiotherapy alone. Two bilateral opposing coaxial fields were used in 10 patients and in the remaining 11 a third frontovertex field was added. Treatment was given in 1.8-2 Gy daily fractions and total dose ranged between 45 and 54 Gy. Treatment was given using a cobalt unit. Four patients treated with somatostatin prior to and 14 patients treated after the end of radiotherapy experienced symptom relief for 6-28 weeks. The 5-year actuarial rate of disease control was 72%. Five out of six failed patients had macroadenomas. Hypopituitarism was observed in 5/21 (24%) patients. Whereas RT alone is effective in the treatment of microadenomas, this is not true for large infiltrative macroadenomas.