Doctor Huashan Hospital, Fudan university, United States
Objectives: : TPIT lineage pituitary neuroendocrine tumors (PitNETs) represent 9% to 19% of non-functioning pituitary adenomas. It exhibits strong invasiveness, making it more prone to recurrence and less responsive to treatment compared to other subtypes. These patients often require comprehensive treatment, and radiosurgery may become a vital postoperative therapy for relapse. Currently, there is a lack of relevant literature on this topic. Our center, affiliated with the National Center for Neurological Disorders, intended to implement research in this area.This study aim to assess the efficacy and safety of stereotactic radiosurgery in treating TPIT- lineage PitNETs.
Methods: : We conducted a retrospective study of 11 female patients at our center who had received Cyberknife treatment. All patients were confirmed with pathological diagnosis of TPit-lineage nonfunctional PitNETs with well-defined immunohistochemistry. The mean age of these patients was 48.3 year-old. All patients experienced tumor recurrence following surgical resection, with 18.2% (2/11) exhibiting compromised visual fields before treatment and 27.3% (3/11) experiencing pituitary dysfunction. Among them, 3 patients underwent staged radiosurgery, while the other 8 patients received fractionated radiosurgery (Median fraction= 3, range from 2 to 5), with single-dose ranges between 4 and 10.2 Gy. Follow-up evaluation included tumor response, pituitary function, and visual function to carry out the efficacy and safety of radiosurgery. Results: : The mean tumor volume before treatment was 16.1 cm3, with an average follow-up period of 41.3 months (range from 12.5 to 76.2m). After Cyberknife radiosurgery, 54.5% (6/11) of patients experienced significant tumor reduction. Among them, 5 out of 6 patients maintained excellent tumor control. In 9.1% (1/11) of cases, the tumor volume increased at 4 months after CKRS, necessitating a second surgical intervention. Analysis result showed the 3-year progression-free survival rate (PFS) was approximately 91%, and the 5-year PFS was approximately 61%. Notably, one patient who received staged radiosurgery experienced a 41.05% reduction in tumor volume 20 months after the initial radiosurgery, followed by further tumor shrinkage after second stage CKRS. None of the patients developed de novo pituitary dysfunction or visual impairment after treatment.
Conclusion(s):: TPIT lineage PitNETs are strongly invasive, with a high recurrence rate, while effective treatment options are currently lacking. Compared to the reported data on Gamma Knife treatment of PitNETs, staged/fractionated CKRS represents similar efficacy. Further, the patients included in this study had larger tumor volumes. Our preliminary research on CKRS for this type of pituitary tumor suggested that radiosurgery provides effective tumor control for postoperative recurrences and potential to be a safe and reliable therapeutic option.