Growth of Pituitary Macroadenomas Postpartial Resection: Implications for Adjuvant Radiotherapy

Abstract

Objective To determine the volumetric growth in macroadenomas (MAs) patients with residual postoperative disease and to identify subpopulations with rapid postoperative growth rate that may benefit from early salvage radiotherapy (RT).

Methods Patients who had undergone a partial resection for MAs and did not receive immediate postoperative RT were eligible. Residual tissue was contoured on serial magnetic resonance imaging and planimetric and volumetric changes in size were measured. Growth rates were established by a single observer using serial volumetric measurements. Data were analyzed to find a relationship among growth rate, adjuvant treatment, and patient and tumor characteristics.

Results Thirty-one patients met the eligibility criteria. Nine patients (29%) required adjuvant treatment because of tumor growth. Volumetric growth was identified 95% of the time compared with 64% planimetrically. Planimetric growth could not be established in 10% of patients showing volumetric changes. Median growth rate was 0.4464 mL/y. Growth rate positively correlated with size of residual postoperative volume (p < 0.001). Receiving salvage treatment positively correlated with growth rate (p = 0.001), particularly at a rate above 2.19 mL/y (p = 0.0064). Five patients (16%) had a growth rate above this level, all of which required salvage treatment. Patients with postoperative residual volume > 3.95 mL were most likely to experience rapid growth rate and require salvage treatment (p = 0.007).

Conclusion Volumetric measurement was found to be superior to planimetric measurement in detecting changes in patients with residual tumors. Patients with postoperative residual volume > 3.95 mL should be considered for early treatment with RT.

Keywords

pituitary - macroadenoma - radiotherapy - surgery - volumetric growth

Note

This study was presented as a poster in the annual meeting of the American Society for Radiation Oncology, San Francisco, CA, September 14–17, 2014.

• References

• 1 Reddy R, Cudlip S, Byrne JV, Karavitaki N, Wass JA. Can we ever stop imaging in surgically treated and radiotherapy-naive patients with non-functioning pituitary adenoma?. Eur J Endocrinol 2011; 165 (05) 739-744
• 2 Bradley KM, Adams CB, Potter CP, Wheeler DW, Anslow PJ, Burke CW. An audit of selected patients with non-functioning pituitary adenoma treated by transsphenoidal surgery without irradiation. Clin Endocrinol (Oxf) 1994; 41 (05) 655-659
• 3 Turner HE, Stratton IM, Byrne JV, Adams CB, Wass JA. Audit of selected patients with nonfunctioning pituitary adenomas treated without irradiation - a follow-up study. Clin Endocrinol (Oxf) 1999; 51 (03) 281-284
• 4 Greenman Y, Ouaknine G, Veshchev I, Reider-Groswasser II, Segev Y, Stern N. Postoperative surveillance of clinically nonfunctioning pituitary macroadenomas: markers of tumour quiescence and regrowth. Clin Endocrinol (Oxf) 2003; 58 (06) 763-769
• 5 O'Sullivan EP, Woods C, Glynn N. , et al. The natural history of surgically treated but radiotherapy-naïve nonfunctioning pituitary adenomas. Clin Endocrinol (Oxf) 2009; 71 (05) 709-714
• 6 Erridge SC, Conkey DS, Stockton D. , et al. Radiotherapy for pituitary adenomas: long-term efficacy and toxicity. Radiother Oncol 2009; 93 (03) 597-601
• 7 Vakilian S, Souhami L, Melançon D, Zeitouni A. Volumetric measurement of vestibular schwannoma tumour growth following partial resection: predictors for recurrence. J Neurol Surg B Skull Base 2012; 73 (02) 117-120
• 8 Molitch ME. Nonfunctioning pituitary tumors. Handb Clin Neurol 2014; 124: 167-184
• 9 Woollons AC, Hunn MK, Rajapakse YR. , et al. Non-functioning pituitary adenomas: indications for postoperative radiotherapy. Clin Endocrinol (Oxf) 2000; 53 (06) 713-717
• 10 Sheehan J, Lee C-C, Bodach ME. , et al. Management of patients with residual or recurrent nonfunctioning pituitary adenomas. Congress of Neurological Surgeons Guidelines 2016. Available at: https://www.cns.org/guidelines/guidelines-management-patients-non-functioning-pituitary-adenomas . Accessed January 23, 2018
• 11 Pomeraniec IJ, Kano H, Xu Z. , et al. Early versus late Gamma Knife radiosurgery following transsphenoidal surgery for nonfunctioning pituitary macroadenomas: a multicenter matched-cohort study. J Neurosurg 2018; 129 (03) 648-657