Prediction of response to endocrine therapy in pronounced cyclical mastalgia using dynamic tests of prolactin release.

Many of the endocrine agents currently used to treat symptomatic benign breast disease modify the action or secretion of prolactin. We have compared the responses to hormonal therapy with dynamic assessment of prolactin control in 29 patients with cyclical mastalgia and in 7 patients with non-cyclical mastalgia. The tests of prolactin release used were direct stimulation by TRH or dopaminergic blockade by domperidone. These were carried out before treatment in the mastalgic patients and also in 22 age-matched asymptomatic controls. The response to treatment was assessed using a special pain chart and visual linear analogue scale. Patients with cyclical mastalgia could be divided into two groups: those in whom the peak prolactin release was exaggerated (greater than 4000 mU/l) and those in whom the prolactin release was less marked and similar to control subjects and patients with non-cyclical mastalgia. Patients in the cyclical mastalgia group with a high peak prolactin release responded to hormonal treatment significantly more frequently (90%) than those with a normal prolactin release (50%). Basal prolactin levels did not correlate with the response to treatment. In the non-cyclical mastalgia group, no patient had peak prolactin release greater than 4000 mU/l and none responded to therapy. This study indicates that dynamic tests of prolactin release in cyclical mastalgia may be useful in predicting the subsequent satisfactory response to endocrine therapy if a high peak prolactin release is induced.