Five years follow-up of invasive prolactinomas with special reference to the control of cavernous sinus invasion

Background Few data are presently available on the effective control of cavernous sinus (CS) invasion of invasive prolactinomas. The aim of this retrospective study, through a mean period of 5 years follow up, is to observe the tumor shrinkage of CS invasive prolactinomas, as well as PRL normalization with bromocriptine therapy. Methods 68 patients met the criteria of invasive prolactinomas (Grade III or IV in the classification scheme of Knosp and colleagues; serum PRL level greater than 200 ng/ml). 33 patients underwent bromocriptine therapy as the initial treatment, and 14 of these 33 had combined treatment with microsurgery and/or radiotherapy. The other 35 patients received microsurgery as the primary treatment, after which two patients had normal PRL without taking bromocriptine and other 33 patients received bromocriptine treatment after microsurgery. Results Tumor volume on magnetic resonance images had completely disappeared in 50 patients (74%), while all the other 18 patients had residual tumor in the parasellar areas, invading the CS, and 14 patients had a secondary empty sella due to tumor shrinkage. Of those 14 patients, seven still had elevated PRL levels; five had optic chiasmal herniation by different degrees (P < 0.05). There were 49 patients with normal PRL levels (72%); five patients with PRL levels more than 200 ng/ml. After the treatment, 14 patients with tumor volume disappearance on MR images and PRL normalization therefore withdrew from bromocriptine therapy. During a subsequent one-and-a-half-year follow-up, tumor recurrence and PRL increase were not found in those 14 patients. Twenty-seven patients maintained normal PRL levels with low-dose bromocriptine, of which 20 patients had their tumor disappear while seven patients had CS residual tumor. Conclusions About three-fourths of prolactinomas with CS invasion can be effectively controlled not only with regard to tumor volume disappearance but also in serum PRL normalization. Residual tumor in the CS areas with PRL normalization and no pressure symptoms can be treated with low-dose of bromocriptine so as to achieve long-term tumor volume control and endocrine control. Great attention should be paid to CS residual tumors accompanying the empty sella, especially in cases with optic chiasmal herniation.