Long-term follow-up of patients with surgical intractable acromegaly after linear accelerator radiosurgery.
OBJECTIVE
Radiotherapy is a crucial treatment for acromegalic patients with growth hormone (GH)-secreting pituitary tumors. However, its effect takes time. We retrospectively reviewed the long-term outcome of linear accelerator stereotactic radiosurgery (LINAC SRS) for patients with acromegaly from the perspective of biochemical remission and associated factors.


METHODS
Twenty-two patients presenting with residual or recurrent (GH)-secreting functional pituitary tumor between 1994 and 2004 who received LINAC SRS were enrolled and followed up for at least 3 years. Residual or recurrent tumor was defined as persistent elevated GH or insulin-like growth factor-1 (IGF-1) level and image-confirmed tumor after previous surgical treatment. Biochemical remission was defined as fasting GH less than 2.5 ng/mL with normal sex-and-age adjusted IGF-1.


RESULTS
The mean follow-up period was 94.7 months (range 36-161 months). Overall mean biochemical remission time was 53 months (median 30 months). Biochemical control was achieved in 15 patients (68.2%) over the follow up period. One patient experienced recurrence after SRS and underwent another operation. Initial GH at diagnosis and pre-SRS GH correlated with biochemical control (p = 0.005 and p < 0.0001, respectively). Further evaluation demonstrated that biochemical control stabilized after 7.5 years. Overall post-SRS hormone deficit persisted in five patients (22.7%).


CONCLUSIONS
In comparison to other radiosurgery modalities, LINAC radiosurgery also provides a satisfactory outcome. SRS has maximum effect over the first 2 years and stabilizes after 7.5 years. Moreover, SRS elicits long-term biochemical effects and requires longer follow-up for better biochemical remission.
Department of Neurosurgery, Chang Gung Memorial Hospital and Chang Gung University, College of Medicine, Taipei, Taiwan.
Jiun-Lin
JL
Yan
Chen-Nen
CN
Chang
Chi-Cheng
CC
Chuang
Peng-Wei
PW
Hsu
Jen-Der
JD
Lin
Kuo-Chen
KC
Wei
Shi-Tseng
ST
Lee
Jen-Kan
JK
Tseng
Ping-Ching
PC
Pai
Yao-Liang
YL
Chen
D000172:Acromegaly / Q000097:blood / Q000209:etiology*; D000236:Adenoma / Q000150:complications / Q000378:metabolism / Q000601:surgery*; D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000378:metabolism / Q000601:surgery*; D010911:Pituitary Neoplasms / Q000150:complications / Q000378:metabolism / Q000601:surgery*; D016634:Radiosurgery; D012074:Remission Induction; D013997:Time Factors; D055815:Young Adult
D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I
LINAC; acromegaly; growth hormone; pituitary gland; radiosurgery