What is the role of surgery in the treatment of pituitary macroadenomas?

Updated: Mar 23, 2018
  • Author: James R Mulinda, MD, FACP; Chief Editor: George T Griffing, MD  more...
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Pituitary macroadenomas often require surgical extirpation for cure. Transsphenoidal surgery is the approach of choice. [9, 10, 11, 12] Only about 1% of patients require a transcranial approach. Compared with remission rates of 90% in microadenomas, macroadenomas with significant extrasellar extension have remission rates of 15-37% when treated with surgery alone. Radiation therapy and medical treatment often complement surgery. [13]

In a study, Han et al compared the 1-nostril and 2-nostril approaches with transsphenoidal surgery. The researchers concluded that the 1-nostril method is fast, minimally invasive, and adequate for resection of most pituitary adenomas. [14]

In a prospective, randomized study, Mao et al investigated whether treatment with lanreotide prior to transsphenoidal surgery for macroadenomas would improve cure rates in patients with newly diagnosed acromegaly. The study included 49 patients who were administered 4 months of preoperative lanreotide treatment and 49 patients who underwent transsphenoidal surgery without pretreatment. The authors reported a 49% cure rate (24 patients) in the pretreatment group following surgery and an 18.4% cure rate (9 patients) in the nonlanreotide group. Mao et al concluded that in patients with growth hormone–secreting pituitary adenomas, preoperative lanreotide treatment increases cure rates from transsphenoidal surgery. [15]

A study by Przybylowski et al found that in patients with nonfunctioning pituitary macroadenomas, those who underwent primary transsphenoidal resection were more likely to develop syndrome of inappropriate antidiuretic hormone secretion than were those who underwent revision transsphenoidal resection. The primary surgery patients were also more likely to undergo gross-total resection of the lesion than were the revision surgery patients (63% vs 28%, respectively). At 2 and 5 years, however, the latter had similar radiologic progression-free survival rates as the patients who underwent primary surgery (possibly because the revision surgery patients had a greater rate of adjuvant radiation therapy). [16]

A retrospective study by Magro et al of 300 patients indicated that endoscopic transsphenoidal surgery for nonfunctioning pituitary macroadenomas has an acceptable rate of complications. The investigators reported worsening visual and pituitary functions in 2.4% and 13.7% of cases, respectively, permanent postoperative diabetes insipidus in 6.2% of cases, and postoperative meningitis in 3.3% of cases, with a strong link seen between meningitis and intraoperative and postoperative cerebrospinal fluid leaks and surgical times of more than 1 hour. [17]

Adenomas with a dumbbell configuration have been difficult to excise with transsphenoidal surgery. Sankhla et al presented their experience with the extended endoscopic endonasal approach (EEEA), concluding that it is a potentially viable option but additional study is needed. [18]

Following transsphenoidal decompression of the anterior optic pathways, a correlation exists between intraoperative MRI results and prognosis of visual deficits. [19]

A study by Hisanaga et al indicated that following surgery for pituitary macroadenoma, the degree to which the optic nerve kinks at the optic canal orifice, as demonstrated using contrast-enhanced FIESTA (fast imaging employing steady state acquisition), independently predicts whether a patient will experience good improvement in visual acuity problems and visual field defect. [20]

Revision surgery for unexpected symptomatic remnants may be avoidable through the use of intraoperative MRI. [19]

A study by Thawani et al found a link between complete resection of pituitary macroadenomas and increased risk of cerebrospinal fluid (CSF) leak. Moreover, use of a fat graft, a nasoseptal flap, or an intraoperative lumbar drain seemed to have limited benefit in lowering the postoperative CSF leak risk. [21]

A study by Johnston et al indicated that in transsphenoidal surgery for Cushing disease, the presence of a macroadenoma and extension of the tumor beyond the pituitary and sella raise the likelihood of nonremission of the disease with the initial surgery and of late recurrence. [22]

In a study of 13 patients, Elhateer et al reported on the effectiveness of fractionated stereotactic radiation therapy (FSRT) in the treatment of macroadenomas. [23] In 12 of the patients, FSRT was employed following tumor resection, while in 1 patient, it served as primary treatment. All but 4 of the patients had nonfunctional macroadenomas. After a median follow-up period of 24 months, the investigators found that local control in the patients was 100% and that 1 patient had a clinically complete response.

According to the authors, the results indicated that FSRT is an effective means of tumor control in patients with pituitary macroadenoma and that it is associated with a low rate of radiation-related morbidity. (No patients were found to have radiation-induced optic neuropathy or radiation-related endocrine dysfunction.) The authors stated, however, that because the study contained so few patients with functioning tumors, they could not judge the hormonal response of macroadenomas to FSRT.

Based on an observational follow-up study (median period, 5.25 y) of 30 patients with pituitary macroadenomas (10 patients with functioning adenomas and 20 with nonfunctioning lesions) that were refractory to conventional surgical and/or medical treatment, Schalin-Jäntti et al also found FSRT to be a beneficial adjuvant therapy for these tumors. [24]

A study by Watts et al indicated that following surgical resection of a nonfunctioning pituitary macroadenoma, the risk of tumor recurrence is greater in patients of younger age at presentation. The investigators also found that of 123 patients in the study, 36 (29%) experienced regrowth of residual tumor or recurrence, ie, the growth of a new adenoma following complete tumor resection. Most patients who experienced regrowth or recurrence did so within 10 years postoperatively. [25]


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