Prediction of recurrence in pituitary tumours: a flow cytometric study using in vivo bromodeoxyuridine.

Although most pituitary tumours are regarded as benign, there is a significant risk of local recurrence and a few are frankly malignant. The prediction of clinically aggressive behaviour by histopathological means is inadequate and the selection of patients for postoperative radiotherapy has often been empirical. The flow cytometric analysis of the DNA content of certain intracranial tumours has suggested a correlation between a high proliferative index and a tendency to recur. The in vivo administration of bromodeoxyuridine (BUdR) yields a reliable and accurate S-phase labelling index and evaluation by flow cytometry allows a much greater and therefore more representative number of cells to be examined. We report our results for the flow cytometric evaluation of the S-phase fraction in a group of 11 human pituitary tumours following the preoperative administration of BUdR and discuss the correlation between high values of S-phase fraction and clinically aggressive behaviour. Initial results suggest a correlation between radiological evidence of tumour invasion and an S-phase greater than 2%.