Adjuvant Radiotherapy Versus Watchful Waiting for World Health Organization Grade II Atypical Meningioma: A Single-Institution Experience

Abstract

BACKGROUND Atypical meningiomas (AMs) are meningiomas that have a higher rate of recurrence than grade I meningioma. Due to the higher risk of recurrence, adjuvant radiotherapy (RT) after resection of AM has been employed. At our institution, some neurosurgeons employ adjuvant RT on all primarily resected AMs, while others employ watchful waiting with serial imaging. OBJECTIVE To study the effect of adjuvant RT on newly resected AMs. METHODS A retrospective review of all AMs primarily resected at our institution from 1996 to 2018 was completed. Data on patient demographics, radiographic findings, use of adjuvant RT, time of follow-up, and recurrences were collected. Adjuvant RT was defined as RT that occurred within 6 mo of initial resection. RESULTS A total of 162 patients met the inclusion criteria. Gross total resection was achieved in 73% of cases. Average time until recurrence in the cohort was 37 mo. A total of 108 patients had adjuvant RT, while 54 patients did not. On multivariate survival analysis, sex, Simpson grade resection, and use of adjuvant RT were independent predictors of recurrence. Mean time to recurrence in patients who received adjuvant RT was 43.7 mo versus 34.7 mo for those who did not receive adjuvant RT. CONCLUSION This study includes the largest retrospective cohort of patients who have received adjuvant RT after primary resection of AM. Our results suggest that the use of adjuvant RT is independently associated with a lower chance of recurrence. These data suggest that practitioners can consider the use of adjuvant RT for newly resected AMs, regardless of Simpson grade resection.

Long-Term Outcomes for Patients With Atypical or Malignant Meningiomas Treated With or Without Radiation Therapy: A 25-Year Retrospective Analysis of a Single-Institution Experience

“…Our study demonstrated significantly improved PFS in patients who received adjuvant RT compared with patients treated with surgery alone (median, 5.9 vs 2.1 years; P = .0017), which is consistent with the results from other series. 7 , 10 , 11 , 17 , 18 , 19 , 20 , 21 , 22 In the largest and most recent of these series, Lee et al reported significantly higher recurrence rates in patients with atypical meningiomas treated with surgery alone compared with surgery and adjuvant RT, with a median time to recurrence of 1.9 versus 4.5 years. 17 Two large studies using data from the National Cancer Database also reported improved OS with adjuvant RT for WHO grade 2 meningiomas.…”

Adjuvant Radiotherapy in Grade II, Atypical Meningioma of the Skull Base

“…24 There are multiple prospective, randomized studies aimed to further investigate the role of ART for the postoperative care of patients with AM, regardless of whether or not GTR was achieved. 19 The phase-II Radiation Therapy Oncology Group (0539 trial) recently reported preliminary data that found no significant difference in progression-free survival between patients with AM who received ART and those who did not. 20,21 The European Organization for Research and Treatment of Cancer (22,024) is another observational prospective trial investigating ART for newly resected AM and grade-III meningioma.…”

“…1 , 63.7 months) was longer than we observed in previously reported data concerning AMs resected at our institution. 19 It is possible that SBL AMs, owing to their possession of fewer histopathological aggressive features than non-SBL AMs need relatively more time to recur. Therefore, ART may be less effective in this population.…”

Single-fraction Stereotactic Radiosurgery for Atypical Meningiomas (WHO grade II): Treatment Results Based on a 25-year Experience

“…The timing and type of radiation treatment in patients with AM is controversial. A number of studies advocate upfront adjuvant EBRT, [8][9][10] some reports favor post-operative surveillance with salvage radiotherapy especially for those following GTR, [11][12][13]18] while a third group advocate for SRS either as an adjuvant or salvage technique. [15,17,19,20] We found that upfront adjuvant SRS and salvage SRS for late recurrences were equally effective, whereas salvage SRS for early recurrence (7-18 months following resection) was a signi cant risk for tumor progression.…”

“…[7] External beam radiation therapy (EBRT) is commonly used to reduce the chance of tumor growth after resection for patients with AM, but no consensus has been reached as to whether or not post-operative EBRT is bene cial. [8][9][10][11][12][13][14] Stereotactic radiosurgery (SRS) is also frequently employed for patients with residual or recurrent AM. [15][16][17][18][19][20] These studies are typically comprised of a heterogeneous group of patients including both AM and MM, patients with genetic conditions such as neuro bromatosis or meningiomatosis, and radiation-induced tumors.…”