Cushing’s disease and aggressive pituitary tumours : Aspects on epidemiology, treatment, and long-term follow-up

Abstract

This thesis focuses on clinical and epidemiological aspects of aggressive pituitary tumours/carcinomas and Cushing's disease. Pituitary carcinomas account for only 0.1-0.2% of the tumours originating from the anterior pituitary gland and are defined solely by the event of distant metastases, whereas aggressive pituitary tumours are defined by their clinical behaviour of rapid/progressive growth despite optimal treatment with surgery, radiotherapy and medical agents. The prognosis for individuals with aggressive tumours/carcinomas has been poor with few treatment options. However, case reports indicated better outcomes after treatment with the alkylating agent temozolomide. In study I and III, we investigated 24 patients (16 aggressive tumours and 8 carcinomas) given treatment with temozolomide. We found an initial response rate (tumour regression ≥30%) in 10/21 evaluable patients, with complete regression in two carcinomas. Favourable response was associated with low tumour expression of the DNA repair protein MGMT; in responders median 9% (range 5-20%) vs non-responders median 93% (50-100%). Our results also indicated a longer survival in patients with low MGMT. Out of 11 patients with MGMT >10%, nine died with an estimated median survival of 26 months (95% CI 14-38), whereas only 1/6 patients with lower MGMT died from tumour progression during a follow-up of median 83 months (range 12-161).