Tuesday, October 6, 2009

Gamma knife radiosurgery: a safe and effective salvage treatment for pituitary tumors not controlled despite conventional radiotherapy

Francesca Swords, , John Monson, , G.m. Besser, , Shern Chew, , Wm Drake, , Ashley Grossman,  and Pn Plowman,

F Swords, Endocrinology, Norfolk and Norwich University Hospitals NHS Foundation Trust , Norfolk, NR4 7UY, United Kingdom
J Monson, Department of Endocrinology, St Bartholomew's Hospital, London, United Kingdom
G Besser, Department of Endocrinology, St Bartholomew's Hospital, London, United Kingdom
S Chew, Department of Endocrinology, St Bartholomew's Hospital, London, United Kingdom
W Drake, Department of Endocrinology, St Bartholomew's Hospital, London, United Kingdom
A Grossman, London, United Kingdom
P Plowman, Department of Oncology, St Bartholomew's Hospital, London, United Kingdom

Francesca Swords, Email: francesca.swords@nnuh.nhs.uk

Objective: We report the use of "Gamma knife" radiosurgery (GK) in 25 patients with pituitary adenomas not cured despite conventional therapy, including external beam radiotherapy.

Patients and Methods: All patients had previously received conventional radiotherapy (CRT) a mean of 11.8 years prior to receiving GK; 23/25 had also undergone pituitary surgery on at least one occasion. Seventeen had hyper-functioning adenomas which were still requiring medical therapy without adequate biochemical control - 10 somatotroph adenomas, 6 corticotroph adenomas and one prolactinoma, while 8 patients had non-functioning pituitary adenomas (NFPAs).

Results: Following GK, mean growth hormone (GH) fell by 49% at 1 year in patients with somatotroph tumours. Serum insulin-like growth factor 1(IGF-1) fell by 32% at 1 year and 38% at 2 years. To date, 80% of patients with acromegaly have achieved normalisation of IGF-1, and 30% have also achieved a mean GH level <1.8ng/ml correlating with normalised mortality. 75% NFPAs showed disease stabilisation or shrinkage post-GK. The patient with a prolactinoma showed a dramatic response: 75% reduction in prolactin at 2 years, with marked shrinkage on magnetic resonance imaging. The results in corticotoph adenomas were variable.

Prior to GK 72% of patients were panhypopituitary, and 42% of the remainder have developed new anterior pituitary hormone deficiencies to date. No other adverse events have been detected at a mean follow up 36.4 months.

Conclusions: These data indicate that GK is a safe and effective adjunctive treatment for patients with NFPAs and acromegaly not satisfactorily controlled with surgery and radiotherapy.

From http://www.eje.org/cgi/content/abstract/EJE-09-0493v1