Karavitaki N et al. (2007) What is the natural history of nonoperated nonfunctioning pituitary adenomas. Clin Endocrinol (Oxf) [doi:10.1111/j.1365-2265.2007.02990.x]

Clinically nonfunctioning pituitary adenomas (NFAs) account for 14.7% of all pituitary adenomas. Since they are not associated with hormonal hypersecretion, most are recognized only when they put pressure on surrounding tissues and cause headaches, visual problems or pituitary hormone deficits.

Symptomatic tumors are treated by surgery followed by radiotherapy to ease symptoms; however, this result is not always achieved, and vision deteriorates after surgery in some patients. Assessing an alternative 'watch and wait' policy is difficult because of the limited number of patients available.

In order to identify factors that could predict which tumors were likely to increase in size, Karavitaki et al. investigated the outcome of a series of consecutive patients with presumed NFAs (microadenoma or macroadenoma) who, for various reasons, were not offered treatment.

They studied 40 patients, of whom 16 had microadenoma and 24 had macroadenoma. During the follow-up period (mean duration 42 months), 12.5% of the microadenomas and 50.0% of the macroadenomas increased in size. Patients with macroadenoma were more likely to experience worsening of visual field defects, particularly if their tumor enlarged. No microadenoma enlarged to cause visual deterioration.

The authors conclude that a 'watch and wait' policy is reasonable for microadenomas but not for macroadenomas, which seem to have a notable growth potential. The choice between surgery and watch and wait should balance the risks of surgery against the probability of tumor enlargement and the loss of advantages associated with an early operation.