INCREASED INCIDENCE OF NEOPLASIA IN PATIENTS WITH PITUITARY-ADENOMAS

OBJECTIVE The goal of our study was to determine the rate of neoplasms in patients with other pituitary adenomas (non-functioning and prolac tinomas) in comparison with acromegaly which is known to favour the de velopment of neoplasia. DESIGN AND PATIENTS We reviewed clinical recor ds for 220 patients with acromegaly, 151 patients with non-functioning pituitary adenoma (NF) and 98 patients with prolactinomas. Incidence rates of cancer for patients with pituitary tumours were calculated pe r person-years of follow-up study. These rates were then compared with sex and age adjusted incidence rates reported by National Tumour Regi stry. An internal control group of 163 subjects with a nonneoplastic c ondition, i.e. Graves' disease followed chronically in the same clinic was also studied. The ratios observed to expected were expressed as s tandardized incidence rates (SIR). The only significant difference bet ween the acromegalic and other pituitary tumours patients was in hypop ituitarism, present in 18.2% (acromegaly) 47% (NF) and 18.6% (prolacti nomas). RESULTS Twenty-three malignant tumours were registered in 19 a cromegalics (1 Hodgkin disease, 1 myelogenous leukaemia, 1 lymphocytic leukaemia, 3 papillary thyroid carcinomas, 1 ovarian carcinoma, 2 col orectal carcinoma, 1 renal cell carcinoma, 4 cervical carcinoma, 2 ski n cancers, 2 pancreatic carcinoma, 4 breast carcinoma, 1 bladder carci noma). Three acromegalics harboured two malignancies. Patients with ac romegaly had a 3.39-fold increased rate of malignant tumours compared with the general population and a 3.21-fold increased rate compared wi th our internal control group. Eleven malignant tumours were found in patients with NF-pituitary adenomas and 2 in prolactinoma patients (1 lymphoma, 1 multiple myeloma, 1 colonic cancer, 1 renal cell cancer, 1 stomach cancer, 2 lung cancers, 1 cervix carcinoma, 1 breast cancer, 1 testicular carcinoma and 3 melanoma). Patients with NF pituitary ade nomas had a 3.91-fold increased rate of malignant tumours compared wit h the general population and 4.07-fold increase compared with the inte rnal control group. Patients harbouring prolactinomas did not have an increased incidence rate of malignancy compared with the general popul ation or our internal controls. Female patients with acromegaly and ma le patients with NF-pituitary adenoma had higher incidences of neoplas ia. CONCLUSION We have demonstrated that the overall incidence of mali gnant tumours in patients with nonfunctioning pituitary adenomas and a cromegaly is significantly higher than expected for general population and for our internal control group.