Feasibility of hippocampus-sparing VMAT for newly diagnosed glioblastoma treated by chemoradiation: pattern of failure analysis

Efficacy and safety of simultaneous integrated boost intensity-modulated radiotherapy combined with temozolomide for the postoperative chemotherapy treatment of multifocal high-grade glioma

Background

The multifocal manifestation of high-grade glioma is a rare disease with an unfavorable prognosis. The pathogenesis of multifocal gliomas and pathophysiological differences in unifocal gliomas are not fully understood. The optimal treatment for patients with multifocal high-grade glioma is not defined in the current guidelines; therefore, individual case series may be helpful as guidance for clinical decision-making.

Methods

Patients with multifocal high-grade glioma treated with simultaneous integrated boost intensity-modulated radiotherapy combined with temozolomide for postoperative treatment at our institution between January 2020 and December 2023 were retrospectively analyzed. Multifocality was neuroradiologically assessed and defined as at least two independent contrast-enhancing foci in the MRI T1 contrast-enhanced sequence. Overall and progression-free survival were calculated from the diagnosis until death and from the start of radiation therapy until the diagnosis of disease progression on MRI for all patients.

Results

A total of 42 patients with multifocal high-grade glioma were examined, of which 16 were female and 26 were male. The median age of all patients was 57 years (range: 23-77 years). The median KPS score was 80 (range: 50-100). Complete resection was performed in 10 cases, and partial resection was performed in 32 cases before the start of radiation therapy. The prescription schedule was 54 Gy (1.8 Gy × 30) with an SIB of 60 Gy (2 Gy × 30). Concomitant temozolomide chemotherapy was administered to 40 patients. Median survival was 19 months (95% CI 14.1-23.8 months) and median progression free survival after initiation of RT 13 months (95% CI 9.2-16.7 months). Five patients experienced grade 3 toxicity, none experienced grade 4 toxicity, and no treatment-related deaths occurred.

Conclusion

Multifocal high-grade gliomas can be treated safely and efficiently with simultaneous integrated boost intensity-modulated radiotherapy with concomitant and adjuvant TMZ chemotherapy.

Optimizing Recurrent Glioblastoma Salvage Treatment: A Multicenter Study Integrating Genetic Biomarkers From the Korean Radiation Oncology Group (21-02)

BACKGROUND AND OBJECTIVES

Few studies have used real-world patient data to compare overall treatment patterns and survival outcomes for recurrent glioblastoma (rGBM). This study aimed to evaluate postprogression survival (PPS) according to the treatment strategy for rGBM by incorporating biomarker analysis.

METHODS

We assessed 468 adult patients with rGBM who underwent standard temozolomide-based chemoradiation. The impact of predictors on PPS was evaluated in patients with isocitrate dehydrogenase wild-type rGBM (n = 439) using survival probability analysis. We identified patients who would benefit from reirradiation (re-RT) during the first progression.

RESULTS

Median PPS was 3.4, 13.8, 6.6, and 10.0 months in the best supportive care (n = 82), surgery (with/without adjuvant therapy, n = 112), chemotherapy alone (n = 170), and re-RT (with/without chemotherapy, n = 75) groups, respectively. After propensity score matching analysis of the cohort, both the surgery and re-RT groups had a significantly better PPS than the chemotherapy-only group; however, no significant difference was observed in PPS between the surgery and re-RT groups. In the surgery subgroup, surgery with chemotherapy ( P = .024) and surgery with radio(chemo)therapy ( P = .039) showed significantly improved PPS compared with surgery alone. In the no-surgery subgroup, radio(chemo)therapy showed significantly improved PPS compared with chemotherapy alone ( P = .047). Homozygous deletion of cyclin-dependent kinase inhibitor 2A/B, along with other clinical factors (performance score and progression-free interval), was significantly associated with the re-RT survival benefit.

CONCLUSION

Surgery combined with radio(chemo)therapy resulted in the best survival outcomes for rGBM. re-RT should also be considered for patients with rGBM at first recurrence. Furthermore, this study identified a specific genetic biomarker and clinical factors that may enhance the survival benefit of re-RT.

Incidence of hippocampal and perihippocampal brain metastases and impact on hippocampal-avoiding radiotherapy: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

In patients requiring prophylactic cranial irradiation (PCI) or whole-brain radiotherapy (WBRT) for brain metastases (BMs), hippocampal avoidance (HA) has been shown to preserve neurocognitive function and quality of life. Here, we aim to estimate the incidence of hippocampal and perihippocampal BMs and the subsequent risk of local undertreatment in patients undergoing hippocampal sparing radiotherapy.

MATERIALS AND METHODS

MEDLINE, Embase, and Scopus were searched with the terms "Hippocampus", "Brain Neoplasms", and related terms. Trials reporting on the incidence of hippocampal and/or perihippocampal BMs or hippocampal failure rate after PCI or WBRT were included.

RESULTS

Forty records were included, encompassing a total of 5,374 patients with over 32,570 BMs. Most trials employed a 5 mm margin to define the HA zone. In trials reporting on BM incidence, 4.4 % (range 0 - 27 %) and 9.2 % (3 - 41 %) of patients had hippocampal and perihippocampal BMs, respectively. The most common risk factor for hippocampal BMs was the total number of BMs. The reported failure rate within the HA zone after HA-PCI or HA-WBRT was 4.5 % (0 - 13 %), salvageable with radiosurgery in most cases. SCLC histology was not associated with a higher risk of hippocampal failure (OR = 2.49; p = 0.23). In trials comparing with a conventional (non-HA) PCI or WBRT group, HA did not increase the hippocampal failure rate (OR = 1.90; p = 0.17).

CONCLUSION

The overall incidence of hippocampal and perihippocampal BMs is considerably low, with a subsequent low risk of local undertreatment following HA-PCI or HA-WBRT. In patients without involvement, the hippocampus should be spared to preserve neurocognitive function and quality of life.

Volumetric modulated arc therapy (VMAT): a review of clinical outcomes—what is the clinical evidence for the most effective implementation?

Modern conformal radiation therapy using techniques such as modulation, image guidance and motion management have changed the face of radiotherapy today offering superior conformity, efficiency, and reproducibility to clinics worldwide. This review assesses the impact of these advanced radiotherapy techniques on patient toxicity and survival rates reported from January 2017 to September 2020. The main aims are to establish if dosimetric and efficiency gains correlate with improved survival and reduced toxicities and to answer the question ‘What is the clinical evidence for the most effective implementation of VMAT?’. Compared with 3DCRT, improvements have been reported with VMAT in prostate, locally advanced cervical carcinoma and various head and neck applications, leading to the shift in technology to VMAT. Other sites such as thoracic neoplasms and nasopharyngeal carcinomas have observed some improvement with VMAT although not in line with improved dosimetric measures, and the burden of toxicity and the incidence of cancer related deaths remain high, signaling the need to further mitigate toxicity and increase survival. As technological advancement continues, large randomised long-term clinical trials are required to determine the way-forward and offer site-specific recommendations. These studies are usually expensive and time consuming, therefore utilising pooled real-world data in a prospective nature can be an alternative solution to comprehensively assess the efficacy of modern radiotherapy techniques.

Multifocal high-grade glioma radiotherapy safety and efficacy

Background

Multifocal manifestation of high-grade glioma is a rare disease with very unfavourable prognosis. The pathogenesis of multifocal glioma and pathophysiological differences to unifocal glioma are not fully understood. The optimal treatment of patients suffering from multifocal high-grade glioma is not defined in the current guidelines, therefore individual case series may be helpful as guidance for clinical decision-making.

Methods

Patients with multifocal high-grade glioma treated with conventionally fractionated radiation therapy (RT) in our institution with or without concomitant chemotherapy between April 2011 and April 2019 were retrospectively analysed. Multifocality was neuroradiologically assessed and defined as at least two independent contrast-enhancing foci in the MRI T1 contrast-enhanced sequence. IDH mutational status and MGMT methylation status were assessed from histopathology records. GTV, PTV as well as the V30Gy, V45Gy and D2% volumes of the brain were analysed. Overall and progression-free survival were calculated from the diagnosis until death and from start of radiation therapy until diagnosis of progression of disease in MRI for all patients.

Results

20 multifocal glioma cases (18 IDH wild-type glioblastoma cases, one diffuse astrocytic glioma, IDH wild-type case with molecular features of glioblastoma and one anaplastic astrocytoma, IDH wild-type case) were included into the analysis. Resection was performed in two cases and stereotactic biopsy only in 18 cases before the start of radiation therapy. At the start of radiation therapy patients were 61 years old in median (range 42–84 years). Histopathological examination showed IDH wild-type in all cases and MGMT promotor methylation in 11 cases (55%). Prescription schedules were 60 Gy (2 Gy × 30), 59.4 Gy (1.8 Gy × 33), 55 Gy (2.2 Gy × 25) and 50 Gy (2.5 Gy × 20) in 15, three, one and one cases, respectively. Concomitant temozolomide chemotherapy was applied in 16 cases, combined temozolomide/lomustine chemotherapy was applied in one case and concomitant bevacizumab therapy in one case. Median number of GTVs was three. Median volume of the sum of the GTVs was 26 cm³. Median volume of the PTV was 425.7 cm³ and median PTV to brain ratio 32.8 percent. Median D2% of the brain was 61.5 Gy (range 51.2–62.7) and median V30Gy and V45 of the brain were 59.9 percent (range 33–79.7) and 40.7 percent (range 14.9–64.1), respectively. Median survival was eight months (95% KI 3.6–12.4 months) and median progression free survival after initiation of RT five months (95% CI 2.8–7.2 months). Grade 2 toxicities were detected in eight cases and grade 3 toxicities in four cases consisting of increasing edema in three cases and one new-onset seizure. One grade 4 toxicity was detected, which was febrile neutropenia related to concomitant chemotherapy.

Conclusion

Conventionally fractionated RT with concomitant chemotherapy could safely be applied in multifocal high-grade glioma in this case series despite large irradiation treatment fields.

Role of hippocampal location and radiation dose in glioblastoma patients with hippocampal atrophy

BACKGROUND

The hippocampus is a critical organ for irradiation. Thus, we explored changes in hippocampal volume according to the dose delivered and the location relative to the glioblastoma.

METHODS

All patients were treated for glioblastoma with surgery, concomitant radiotherapy and temozolomide, and adjuvant temozolomide. Hippocampi were retrospectively delineated on three MRIs, performed at baseline, at the time of relapse, and on the last MRI available at the end of follow-up. A total of 98, 96, and 82 hippocampi were measured in the 49 patients included in the study, respectively. The patients were stratified into three subgroups according to the dose delivered to 40% of the hippocampus. In the group 1 (n = 6), the hippocampal D_40% was < 7.4 Gy, in the group 2 (n = 13), only the H_contra D_40% was < 7.4 Gy, and in the group 3 (n = 30), the D_40% for both hippocampi was > 7.4 Gy.

RESULTS

Regardless of the time of measurement, homolateral hippocampal volumes were significantly lower than those contralateral to the tumor. Regardless of the side, the volumes at the last MRI were significantly lower than those measured at baseline. There was a significant correlation among the decrease in hippocampal volume regardless of its side, and D_max (p = 0.001), D_98% (p = 0.028) and D_40% (p = 0.0002). After adjustment for the time of MRI, these correlations remained significant. According to the D_40% and volume at MRI_last, the hippocampi decreased by 4 mm³/Gy overall.

CONCLUSIONS

There was a significant relationship between the radiotherapy dose and decrease in hippocampal volume. However, at the lowest doses, the hippocampi seem to exhibit an adaptive increase in their volume, which could indicate a plasticity effect. Consequently, shielding at least one hippocampus by delivering the lowest possible dose is recommended so that cognitive function can be preserved. Trial registration Retrospectively registered.