Stereotactic Radiosurgery (SRS) with or without Surgical Resection for Pituitary Adenoma: Insights from the National Cancer Database

Introduction: Stereotactic radiosurgery (SRS) is an effective option for inadequately resected or recurrent pituitary adenoma. Herein, we evaluated the characteristics and outcomes of patients undergoing SRS for pituitary adenoma using a national cancer registry.

Methods: National Cancer Database (NCDB) was queried for cases diagnosed with pituitary adenoma (ICD-O-3 code: 8272) and treated with SRS between 2004 and 2017. Patients were grouped into (1) SRS alone and (2) SRS and surgical resection. Demographic, clinical, and treatment characteristics were compared between the two groups. Kaplan–Meier survival curves and cox-regression analyses were performed to evaluate the impact of treatment type on survival.

Results: A total of 1,625 patients undergoing SRS (Gamma-knife: 894, 55%, LINAC/Cyber-knife: 266, 16.4%, and unspecified: 465, 28.6%) for pituitary adenoma were identified. Of these, 1,189 (73.2%) also underwent a surgical procedure, and 436 (26.8%) underwent SRS alone. Of those who underwent a surgical procedure; 15.4% (n = 183) underwent a biopsy, 73.1% (n = 869) sub-total resection, and 11.4% (n = 136) gross-total resection. Almost all patients in the surgical group had a histological diagnosis (99.6%) while most patients (81.2%) in the SRS alone group had a radiographic diagnosis only. Compared with patients undergoing SRS plus surgery, patients undergoing SRS alone were more likely to be older (>65: 43.3%, n = 189 vs 14.4%, n = 171; p < 0.001), more likely to be female (55%, n = 240 vs. 49.2%, n = 585, p < 0.001), have smaller tumors (≤3 cm; 92.1% vs. 65.4%, p < 0.001), delayed treatment (days from diagnosis to treatment; 98 ± 123.4 vs. 39.8 ± 67.2, p < 0.001) Among those who underwent SRS following surgical resection, the average time between surgery and SRS was 4 months (138.9 days ± 158.9). The mortality rate of the cohort was 13.3%. Five-year survival rate for the SRS-alone group was found to be 79.3% (95% CI: 75.1–83.8), which was significantly lower compared with patients undergoing SRS following surgical resection (94.2%; 95% CI: 92.7–95.7; p < 0.001). On cox regression analysis, adjusting for sex, age, tumor size, and comorbidity, factors found to be significantly associated with increased odds of mortality included male sex (HR: 1.47, 95% CI: 1.07–2.02, p = 0.018), older age (>65 vs. <18: HR: 7.98, 95% CI: 1.10–57.66, p = 0.04), and higher comorbidity (Charlson's score of 2 or more vs. 0: HR: 1.51, 95% CI: 1.04–2.20, p = 0.031). Moreover, compared with patients undergoing SRS alone, those undergoing biopsy followed by SRS (HR: 0.49, 95% CI: 0.27–0.92, p = 0.025), those undergoing subtotal resection followed by SRS (HR: 0.44, 95% CI: 0.30–0.64, p < 0.001) and those undergoing gross-total resection followed by SRS (HR: 0.40, 95% CI: 0.20–0.82, p = 0.013) were all found to have a significantly lower risk of mortality.

Conclusion: Our analyses indicate that tumors that are amenable to surgical resection, which then either recur (SRS following GTR) or are inadequately resected (STR following SRS) may benefit most from postoperative SRS, compared with tumors that may not be amenable to surgical resection due to concomitant comorbidities or other patient factors which are then treated with SRS alone. Therefore, judicious use of SRS, in conjunction with standard therapy, may help optimize patient outcomes among patients with pituitary adenomas.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
12 February 2021