Clinical/disease sites: CNS and haematology

Abstract

Purpose: Postoperative radiotherapy (PORT) results in excellent local tumour control and improvement of excessive hormonal secretion in pituitary adenoma patients where (repeated) surgery was unsuccessful. Despite this benefit, concerns related to possible long term side effects are often quoted to delay or reject this treatment. In previous studies. the incidence of second tumours and mortality in pituitary adenoma patients treated with PORT were compared with a normal reference population. For proper evaluation however, a direct comparison with similar patients treated with surgery alone should be made. The purpose of this study was to assess the impact of PORT on developing second tumours and mortality in pituitary adenoma patients by comparing the incidence with patients treated with surgery alone. Materials: A retrospective study was performed in 462 pituitary adenoma patients (non-functioning adenoma n=256. growth-hormone secreting n=139 and adrenocorticotropic-hormone secreting adenoma n= 67) treated between t959 and 2008 at the University Medical Center Groningen. PORT was performed in 236 pituitary adenoma patients. The different radiotherapy techniques used in this period were divided into techniques with (n=80) or without (n=153) a beam configuration directed into the central body axis of the patient. Most patients received a radiation fractionation scheme of 25 daily fractions of 1.8 Gy in 5 weeks.After pituitary adenoma diagnosis the incidence of tumours and death were investigated using median life expectancy (MLE). MLE was used to correct for year of birth and gender and with the application of years of follow up as a time base for a left-censored log-rank test. Results: Median age at diagnosis was 47 (range 10-83) years and median overall follow-up time was 9 (range 1-49) years. The median follow-up time of patients treated with PORT was 14 (range 1-49) years and 6 (range 134) years in patients treated with surgery alone. Four patients developed an intracranial tumour, 3 of them were treated with PORT. Twenty-one patients treated with PORT developed an extracranial tumour compared to 11 patients treated with surgery alone (RR 1.04 CI 95%, 0.50-2.17, P = 0.917). In 11 out of the 21 patients treated with PORT and diagnosed with an extracranial tumour a central body axis radiotherapy technique was used (RR 1.43 CI 95%, 0.60-3.41, P = 0.425).Forty-five patients treated with PORT died compared to 24 patients treated with surgery alone (RR 1.26 CI 95%, 0.77-2.08, P = 0.358). Conclusions: Postoperative radiotherapy did not increase the incidence of second tumours and mortality in pituitary adenoma patients. Central body axis radiotherapy technique was not associated with an increase in extracranlal tumours.