William T. Couldwell, M.D., Ph.D., and Martin H. Weiss, M.D.
Departments of Surgery and Neuroscience, University of North Dakota, Minot, North Dakota; and Department of Neurosurgery, University of Southern California, Los Angeles, California
Key Words * hyperprolactinemia * microadenoma
We, as other authors, have noted that late relapse of hyperprolactinemia following apparent successful adenomectomy in women harboring microprolactinomas is not rare.[1-3]
On retrospective review of a series of tumors treated at the University of Southern California teaching hospitals, we have found that the immediate postoperative prolactin level may be predictive of late recurrence of hyperprolactinemia.[4] It is our routine to ascertain prolactin levels at 3 days and 6 weeks postoperatively. Of 133 patients undergoing microadenomectomy who had 3-day postoperative prolactin levels of less than 10 µg/L (the vast majority of these were less than 3 µg/L), 132 or 99% had prolactin levels of less than 20 µg/L at their 6-week follow-up examination. At 5 years postoperatively, 130 (98%) of the original 133 patients still had normal prolactin levels. However, of 43 patients who had 3-day postoperative prolactin levels in the range of 10 to 20 µg/L, only 32 (74%) had prolactin levels in the normal range at 6 weeks postoperatively, and only five (16%) of this group of 32 patients had normal prolactin levels at 5-year follow-up review. Therefore, although 18% of patients who have a normal postoperative prolactin level at 6 weeks will develop recurrent hyperprolactinemia when followed for 5 years, only three (7%) of 41 represent patients with immediate prolactin levels of less than 10 µg/L, whereas the remainder were in the group with immediate postoperative prolactin levels in the 10 to 20 µg/L range.
These data indicate that the traditional criteria used to determine successful microadenoma resection in the immediate postoperative period (prolactin level of less than 20 µg/L) may be too liberal; in our series the patient with an immediate postoperative prolactin of less than 10 µg/L had an approximately 98% chance of long-term chemical cure, and we have yet to see a recurrence of hyperprolactinemia in a patient whose immediate postoperative prolactin level was less than 3 µg/L.
References
1. Rodman EF, Molitch ME, Post KD, et al: Long-term follow-up of transsphenoidal selective adenomectomy for prolactinoma. JAMA 252:921924, 1984
2. Serri O, Hardy J, Massoud F: Relapse of hyperprolactinemia revisited. N Engl J Med 329:1357, 1993 (Letter)
3. Serri O, Rasio E, Beauregard H, et al.: Recurrence of hyperprolactinemia after selective transsphenoidal adenomectomy in women with prolactinoma. N Engl J Med 309:280283, 1983
4. Weiss MH: Role of surgical intervention for prolactinomas, in Melmed S, Robbins RJ, (eds): Molecular and Clinical Advances in Pituitary Disorders. Blackwell Scientific Publications, 1991, pp 255260
Manuscript received June 3, 1996.
Accepted in final form June 10, 1996.
Address reprint requests to: William T. Couldwell, M.D., Ph.D., Trinity Medical Center, One Burdick Expressway West, Minot, North Dakota 58701.
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