Postoperative radiation therapy for pituitary adenoma.
BACKGROUND
We evaluated the efficacy of postoperative radiation therapy (RT), prognostic factors for local control probability, dose response relationship and treatment sequelae in 75 patients with pituitary adenoma.


METHODS
A total dose of 48-60 Gy (median: 50 Gy) was delivered with a conventional fractionation schedule after surgery. Of 75 patients, 55 (73%) were followed for more than 5 years and 27 (36%) were followed for more than 10 years with a median of 95 months.


RESULTS
Five- and 10-year local control probabilities were 87.1% and 85.0%, respectively. Univariate analysis revealed that age (p = 0.007), tumor volume smaller than 30 cm3 (p = 0.018) and the absence of prolactin secretion (p = 0.003) were significantly favorable prognostic factors for local control probability. After multivariate analysis combining these 3 factors, tumor volume smaller than 30 cm3 (p = 0.017) and age (p = 0.039) were statistically significant. Patients with prolactinoma greater than 30 cm3 showed particularly poor local control rates. No significant improvement of the local control rate was detected with increasing total irradiation doses between 48 and 60 Gy (p = 0.29). The most common side effect was hypopituitarism, and there were no severe sequelae such as optic neuropathy or brain necrosis.


CONCLUSIONS
Except with prolactinoma, the dose of postoperative RT for pituitary adenoma should not exceed 50 Gy. Large prolactinoma, however, was very difficult to control with the irradiation doses between 50 and 60 Gy, and would be good candidates for stereotactic radiosurgery or stereotactic radiation therapy.
Isobe
K
K
Department of Radiology, Chiba University, School of Medicine, Japan.
Ohta
M
M
Yasuda'
S
S
Uno
T
T
Hara
R
R
Machida
N
N
Saeki
N
N
Yamaura
A
A
Shigematsu
N
N
Ito
H
H
D000236:Adenoma / Q000737:chemistry / Q000532:radiotherapy* / Q000601:surgery; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D018237:Germinoma; D006801:Humans; D015993:Life Tables; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis; D009364:Neoplasm Recurrence, Local; D016609:Neoplasms, Second Primary; D010908:Pituitary Hormones, Anterior / Q000032:analysis; D010911:Pituitary Neoplasms / Q000737:chemistry / Q000532:radiotherapy* / Q000601:surgery; D011184:Postoperative Period; D011379:Prognosis; D015175:Prolactinoma / Q000737:chemistry / Q000532:radiotherapy / Q000601:surgery; D016016:Proportional Hazards Models; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D016896:Treatment Outcome
D009363:Neoplasm Proteins; D010908:Pituitary Hormones, Anterior