Yeboa, D.N.

OBJECTIVE Spinal stereotactic radiosurgery (SSRS) is an established treatment modality for spinal metastatic disease. A common complication of SSRS is postradiation pathologic fracture. The authors evaluated the risk of pathologic fracture in sacral SSRS. METHODS All patients receiving SSRS in 1 to 5 fractions to 1 or more sacral levels between 2011 and 2020 at participating institutions were included. Demographic, histological, anatomical, and outcome data were obtained from electronic medical records. Data were analyzed using SPSS version 28. RESULTS Of 67 total patients, 50 (74.6%) were men and 17 (25.4%) were women. The most common tumor histologies were prostate adenocarcinoma (n = 16 [23.9%]) and renal cell carcinoma (n = 12 [17.9%]). Median (range) age at treatment was 63 (8–87) years. The mean ± SD (range) number of levels treated was 1.5 ± 0.7 (1–4) levels. Mean ± SD (range) bone density at S1 was 208.0 ± 74.4 (−3.0 to 443.3) Hounsfield units (HUs). Median (range) follow-up was 16.6 (1.5–132) months, median ± SD (range) overall survival was 24 ± 21.0 (1.7–83.3) months, and the 1-year local control rate was 83.6%. Fourteen patients (20.9%) experienced fracture within the radiation field. There was no association between fracture and patient sex (p = 0.32), age (p = 0.40), S1 HU (p = 0.28), tumor location according to Denis classification (p = 0.87), presence of pain (p = 0.66), single versus multifraction radiation (p = 0.44), or number of levels treated (p = 0.52). Patients experiencing in-field progression were more likely to experience fracture (61.5% vs 10.2%, p < 0.001), and patients experiencing fracture had a higher average Spine Instability Neoplastic Score than patients without fracture (5.7 vs 4.3, p = 0.049). Only local control remained as a factor associated with sacral fracture in the multivariate analysis. Of the patients experiencing fracture, 10 (71.4%) were symptomatic and 3 of those (30.0%) underwent post-SSRS surgical intervention. CONCLUSIONS Pathologic fracture may occur after sacral SSRS in a significant number of patients and is significantly associated with failure of local control.

Abstract PURPOSE/OBJECTIVE We seek to establish the feasibility of using spine stereotactic radiosurgery (SSRS) allowing for spinal cord dose constraint relaxation as the primary management of metastatic epidural spinal cord compression (MESCC) in inoperable patients monitoring for radiation myelopathy (RM) and radiographic local control (LC). MATERIAL/METHODS Patients with radiation naïve MESCC were enrolled on this prospective Phase 1 trial. Single fraction SSRS was delivered to a dose of 18 or 24 Gy. Spinal cord constraint relaxation was performed in sequential cohorts from an initial allowable Dmax cohort of 10 Gy up to 16 Gy only if tumor progression occurred without RM. RESULTS Thirty two patients enrolled on the trial of which 4, 12, 8 and 8 were in the 10 Gy, 12 Gy, 14 Gy and 16 Gy cord Dmax cohorts, respectively. At baseline, there were 10 sites with MESCC Grade 1B, 10 sites with Grade 1C, 9 sites with Grade 2, 2 sites with Grade 1A, and 1 site with Grade 3 disease. Of the 28 evaluable patients, the median overall survival was 32.3 months (range 5.8-122.6 mo). The 1-year and 5-year LC was 84.5% and 79.5%. The 2-year LC did not statistically differ between the 14-16 Gy cord Dmax combined cohorts and the 10-12 Gy cord Dmax combined cohorts (92.9% vs. 62.9%, p = 0.15). With a median clinical follow-up of 22.7 months (range 3-122.3 mo), there were no cases of RM including in the 13 patients who survived at least 3 years. In the cohort receiving a cord Dmax of 16 Gy, there were no cases of RM with a median follow-up of 18.6 mo (range 9.0-97.1 mo). CONCLUSION With long-term follow-up, these data demonstrate that SSRS is a safe and effective tool in patients with MESCC. Cord constraint relaxation may be considered in inoperable patients with MESCC.

Abstract Background Medulloblastoma in adults is rare and treatment decisions are largely driven from pediatric literature. We sought to characterize recurrent medulloblastoma in adults. Methods From a single-institution dataset of 200 adult patients diagnosed with medulloblastoma during 1978–2017, those with recurrence were analyzed for clinical features, treatment, and outcome. Results Of the 200 patients, 82 (41%) with median age of 29 years (18–59) had recurrence after a median follow-up time of 8.4 years (95% CI = 7.1, 10.3). Of these, 30 (37%) were standard-risk, 31 (38%) were high-risk, and 21 (26%) had unknown-risk diseases at the time of initial diagnosis. Forty-eight (58%) presented with recurrence outside the posterior fossa, of whom 35 (43%) had distant recurrence only. Median Progression-free survival (PFS) and OS from initial surgery were 33.5 and 62.4 months, respectively. Neither PFS nor OS from initial diagnosis differed between the standard-risk and high-risk groups in those who experience recurrence (P = .505 and .463, respectively). Median OS from first recurrence was 20.3 months, also with no difference between the standard-risk and high-risk groups (P = .518). Recurrences were treated with combinations of re-resection (20 patients; 25%), systemic chemotherapy (61 patients; 76%), radiation (29 patients; 36%), stem cell transplant (6 patients; 8%), and intrathecal chemotherapy (4 patients; 5%). Patients who received radiation at recurrence had better OS (32.9 months) than those who did not (19.2 months) (P = .034). Conclusions Recurrent medulloblastoma in adults has a poor prognosis irrespective of initial risk stratification. Recurrence commonly arises outside the posterior fossa years after initial diagnosis.

Abstract Brain metastases are a challenging manifestation of renal cell carcinoma. We have a limited understanding of brain metastasis tumor and immune biology, drivers of resistance to systemic treatment, and their overall poor prognosis. Current data support a multimodal treatment strategy with radiation treatment and/or surgery. Nonetheless, the optimal approach for the management of brain metastases from renal cell carcinoma remains unclear. To improve patient care, the authors sought to standardize practical management strategies. They performed an unstructured literature review and elaborated on the current management strategies through an international group of experts from different disciplines assembled via the network of the International Kidney Cancer Coalition. Experts from different disciplines were administered a survey to answer questions related to current challenges and unmet patient needs. On the basis of the integrated approach of literature review and survey study results, the authors built algorithms for the management of single and multiple brain metastases in patients with renal cell carcinoma. The literature review, consensus statements, and algorithms presented in this report can serve as a framework guiding treatment decisions for patients. CA Cancer J Clin. 2022;72:454‐489.

Abstract Background Brainstem toxicity after radiation therapy (RT) is a devastating complication and a particular concern with proton radiation (PBT). We investigated the incidence and clinical correlates of brainstem injury in pediatric brain tumors treated with PBT. Methods All patients &lt;21 years with brain tumors treated with PBT at our institution from 2007–2019, with a brainstem Dmean &gt;30 Gy and/or Dmax &gt;50.4 Gy were included. Symptomatic brainstem injury (SBI) was defined as any new or progressive cranial neuropathy, ataxia, and/or motor weakness with corresponding radiographic abnormality within brainstem. Results A total of 595 patients were reviewed and 468 (medulloblastoma = 200, gliomas = 114, ependymoma = 87, ATRT = 43) met our inclusion criteria. Median age at RT was 6.3 years and median prescribed RT dose was 54Gy [RBE]. Fifteen patients (3.2%) developed SBI, at a median of 4 months after RT. Grades 2, 3, 4, and 5 brainstem injuries were seen in 7, 5, 1, and 2 patients respectively. Asymptomatic radiographic changes were seen in 51 patients (10.9%). SBI was significantly higher in patients with age ≤3 years, female gender, ATRT histology, patients receiving high-dose chemotherapy with stem cell rescue, and those not receiving craniospinal irradiation. Patients with SBI had a significantly higher V50–52. In 2014, our institution started using strict brainstem dose constraints (Dmax ≤57 Gy, Dmean ≤52.4 Gy, and V54≤10%). There was a trend towards decrease in SBI from 4.4% (2007-2013) to 1.5% (2014–2019) (P = .089) without affecting survival. Conclusion Our results suggest a low risk of SBI after PBT for pediatric brain tumors, comparable to photon therapy. A lower risk was seen after adopting strict brainstem dose constraints.

AbstractBackgroundAdult medulloblastoma (MB) is rare, and management guidelines are largely based on pediatric clinical trials and retrospective series. Limited data exist with respect to clinical characteristics, prognostic factors, and outcomes based on first-line treatments.MethodsTwo hundred adults with MB seen at a single institution from January 1978 to April 2017 were identified and followed for a median of 8.4 y (7.1, 10.3).ResultsPatient’s median age at diagnosis was 29 y (18, 63). One hundred eleven (55.5%) were standard-risk, 59 (29.5%) were high-risk, and 30 (15.0%) were indeterminate. Most received post-operative radiation (RT) (184 [92.0%]), and 105 (52.5%) received first-line chemotherapy. Median overall survival (OS) was 8.8 y (7.2, 12.2) and median progression-free survival (PFS) was 6.6 y (4.9, 11.2). High-risk patients had inferior OS (Hazard ratio [HR] = 2.5 [1.5, 4.2], P = .0006) and PFS (HR = 2.3 [1.3, 3.9], P = .002) compared to standard-risk patients. Age, sex, and metastatic disease were not associated with survival. After adjusting for risk status, those who received RT plus adjuvant chemotherapy had superior PFS compared to RT plus neoadjuvant chemotherapy [HR = 0.46 (0.22, 0.95), P = .0357]. Within a subgroup for whom detailed clinical data were available, those who received RT plus adjuvant chemotherapy had improved PFS compared to RT only [HR = 0.24 (0.074–0.76), P = .016]. The substitution of cisplatin for carboplatin and the elimination of vincristine did not negatively affect outcomes.ConclusionThis is the largest single-institution retrospective study of adult MB to our knowledge and identifies standard-risk status, first-line RT and adjuvant chemotherapy as factors associated with improved outcomes.

Abstract PURPOSE/OBJECTIVE Dose constraints for re-irradiation of recurrent primary brain tumors are not well-established, especially for treatment volumes too large for stereotactic radiotherapy. This prospective trial was performed to test dose constraints for conventionally-fractionated re-irradiation of recurrent primary brain tumors MATERIALS/METHODS A single-institution, prospective trial of 21 adults with recurrent brain tumors was performed. Electronic dosimetry records from the first course of radiation (RT1) were obtained and deformed onto the simulation CT for the second course of radiation (RT2). Treatment plans for RT2 were developed that met protocol-assigned dose constraints for RT2 alone and the composite dose of RT1+RT2. Dose constraints were also based on histology and interval since RT1. The primary endpoint was the rate of symptomatic brain necrosis after RT2. RESULTS Twenty one adults enrolled from March 2017 to May 2018. Twelve had glioblastoma, four had oligodendroglioma, two had anaplastic astrocytoma, and one each had choroid plexus papilloma, hemangiopericytoma, and pleomorphic xanthroastrocytoma (PXA). Twenty patients were treated with VMAT and one was treated with proton CSI. Median RT1-RT2 interval was 45 months (range, 9–141 months). Median RT2 dose was 42.8 Gy (range, 17.5–60 Gy). Median PTV volume was 208 cc (range, 7–1537 cc). Median imaging followup was 9 months (range, 1–20 months). Two months after RT2, the patient with PXA developed a trapped temporal horn adjacent to the RT2 treatment volume; pathology from emergent resection revealed necrotic brain tissue. The patient recovered fully and lived another 18 months until dying of disease progression. No other patient developed symptomatic radionecrosis. Median overall survival from RT2 for all patients was 11 months (range, 3–20 months). CONCLUSION Re-irradiation can be performed with conventionally fractionated schemes. Given the low rate of symptomatic radionecrosis, the dose constraints described here are a starting point for future studies of conventionally fractionated re-irradiation.

Abstract INTRODUCTION Prospective studies for adult medulloblastoma (MB) are scarce and management guidelines are largely derived from pediatric experience and retrospective data. However, adult MB is a distinct disease for which limited data exist regarding clinical characteristic, prognostic factors, outcome based on upfront treatment, or patterns of recurrence. METHODS 200 patients (≥18 years at diagnosis) were identified from 1978 to 2017. Survival analysis was performed using the Kaplan-Meier method. RESULTS Median age at diagnosis 29 (18–63); 111 (55.5%) standard-risk (SR), 59 (29.5%) high-risk (HR), 30 (15%) unknown. 188 (94%) and 97 (48.5%) underwent radiotherapy and upfront chemotherapy, respectively. Median PFS: 6.28 years (4.9–11.2); median OS: 8.8 (7.8–12.4) years. Median time to first recurrence: 8.2 (5.1-not reached); 5-year recurrence-free rate: 71% in SR and 45% in HR patients. Survival after first recurrence: 2 years (1.64–2.4). Documented recurrence and risk group were associated with survival (HR 30.4, p< 0.0001 and 2.33, p< 0.001), but metastatic status and local vs. distant recurrence were not. The effect of upfront chemotherapy on survival did not reach statistical significance in SR patients. The use of chemotherapy regimens with or without vincristine or containing cisplatin vs. carboplatin, did not alter the survival outcome. In a subgroup of 57 SR patients who were seen at initial diagnosis and for whom complete staging and treatment information were available 3 and 5-year PFS were 94% (88%, 100%) and 76% (66%, 86%); OS at 5 years, 94% (87%, 100%). CONCLUSION No statistically significant difference was noted in outcome of patients treated without vincristine or with carboplatin instead of cisplatin, suggesting attenuated upfront regimens could be considered to reduce toxicity. Adult MB patients recur late and have a poor post-recurrence survival, therefore long-term follow-up, development of molecular risk-adjusted upfront treatment, and optimization of rescue treatments are needed.