Low expression of Ki-67/MIB-1 labeling index in IDH wild type glioblastoma predicts prolonged survival independently by MGMT methylation status.

PURPOSE: The Ki-67/MIB-1 labeling index (LI) is clinically used to differentiate between high and low-grade gliomas, while its prognostic value remains questionable. Glioblastoma (GBM) expressing wild-type isocitrate dehydrogenase IDHwt, a relatively common malignant brain tumor in adults, is characterized by a dismal prognosis. Herein, we have retrospectively investigated the prognostic role of Ki-67/MIB-1-LI in a large group of IDHwt GBM. METHODS: One hundred nineteen IDHwt GBM patients treated with surgery followed by Stupp's protocol in our Institution between January 2016 and December 2021 were selected. A cut-off value for Ki-67/MIB-1-LI was used with minimal p-value based approach. RESULTS: A multivariate analysis showed that Ki-67/MIB-1-LI expression < 15% significantly correlated with a longer overall survival (OS), independently from the age of the patients, Karnofsky performance status scale, extent of surgery and O6-methylguanine (O6-MeG)-DNA methyltransferase promoter methylation status. CONCLUSIONS: Among other studies focused on Ki-67/MIB-1-LI, this is the first observational study showing a positive correlation between OS of IDHwt GBM patients and Ki-67/MIB-1-LI that we propose as a new predictive marker in this subtype of GBM.

The evolving role of reirradiation in the management of recurrent brain tumors.

Despite aggressive management consisting of surgery, radiation therapy (RT), and systemic therapy given alone or in combination, a significant proportion of patients with brain tumors will experience tumor recurrence. For these patients, no standard of care exists and management of either primary or metastatic recurrent tumors remains challenging.Advances in imaging and RT technology have enabled more precise tumor localization and dose delivery, leading to a reduction in the volume of health brain tissue exposed to high radiation doses. Radiation techniques have evolved from three-dimensional (3-D) conformal RT to the development of sophisticated techniques, including intensity modulated radiation therapy (IMRT), volumetric arc therapy (VMAT), and stereotactic techniques, either stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT). Several studies have suggested that a second course of RT is a feasible treatment option in patients with a recurrent tumor; however, survival benefit and treatment related toxicity of reirradiation, given alone or in combination with other focal or systemic therapies, remain a controversial issue.We provide a critical overview of the current clinical status and technical challenges of reirradiation in patients with both recurrent primary brain tumors, such as gliomas, ependymomas, medulloblastomas, and meningiomas, and brain metastases. Relevant clinical questions such as the appropriate radiation technique and patient selection, the optimal radiation dose and fractionation, tolerance of the brain to a second course of RT, and the risk of adverse radiation effects have been critically discussed.

Long-term treatment outcomes of temozolomide-based chemoradiation in patients with adult-type diffuse IDH-mutant grade 2 astrocytoma.

PURPOSE: To report the long-term outcomes in adult patients with grade 2 IDH-mutant astrocytoma treated with temozolomide (TMZ)-based chemoradiation. METHODS: One hundred and three patients with histologically proven grade 2 astrocytoma received radiation therapy (RT), 50.4-54 Gy in 1.8 Gy fractions, and adjuvant TMZ up to 12 cycles. Fifty-two patients received RT at the time of tumor progression and 51 in the early postoperative period for the presence of at least one high-risk feature (age > 40 years, preoperative tumor size > 5 cm, large postoperative residual tumor, tumor crossing the midline, or presence of neurological symptoms). Overall survival (OS) and progression-free survival (PFS) were calculated from the time of diagnosis. RESULTS: With a median follow-up time of 9.0 years (range, 1.3-15 years), median PFS and OS times were 9 years (95%CI, 6.6-10.3) and 11.8 years (95%CI, 9.3-13.4), respectively. Median PFS was 10.6 years in the early treatment group and 6 years in delayed treatment group (hazard ratio (HR) 0.30; 95%CI 0.16-0.59; p = 0.0005); however, OS was not significantly different between groups (12.8 vs. 10.4 years; HR 0.64; 95%CI 0.33-1.25; p = 0.23). Extent of resection, KPS, and small residual disease were associated with OS, with postoperative tumor ≤ 1 cc that emerged as the strongest independent predictor (HR: 0.27; 95%CI 0.08-0.87; p = 0.01). CONCLUSIONS: TMZ-based chemoradiation is associated with survival benefit in patients with grade 2 IDH-mutant astrocytoma. For this group of patients, chemoradiation can be deferred until time of progression in younger patients receiving extensive resection, while early treatment should be recommended in high-risk patients.

Radiation therapy for atypical and anaplastic meningiomas: an overview of current results and controversial issues.

Meningiomas are the most common intracranial tumors. Most meningiomas are WHO grade 1 tumors whereas less than one-quarter of all meningiomas are classified as atypical (WHO grade 2) and anaplastic (WHO grade 3) tumors, based on local invasiveness and cellular features of atypia. Surgical resection remains the cornerstone of meningioma therapy and represents the definitive treatment for the majority of patients; however, grade 2 and grade 3 meningiomas display more aggressive behavior and are difficult to treat. Several retrospective series have shown the efficacy and safety of postoperative adjuvant external beam radiation therapy (RT) for patients with atypical and anaplastic meningiomas. More recently, two phase II prospective trials by the Radiation Therapy Oncology Group (RTOG 0539) and the European Organisation for Research and Treatment of Cancer (EORTC 2042) have confirmed the potential benefits of fractionated RT for patients with intermediate and high-risk meningiomas; however, several issues remain a matter of debate. Controversial topics include the timing of radiation treatment in patients with totally resected atypical meningiomas, the optimal radiation technique, dose and fractionation, and treatment planning/target delineation. Ongoing randomized trials are evaluating the efficacy of early adjuvant RT over observation in patients undergoing gross total resection.

Stereotactic radiotherapy for brain oligometastases.

Brain metastases, the most common metastases in adults, will develop in up to 40% of cancer patients, accounting for more than one-half of all intracranial tumors. They are most associated with breast and lung cancer, melanoma and, less frequently, colorectal and kidney carcinoma. Magnetic resonance imaging (MRI) is the gold standard for diagnosis. For the treatment plan, computed tomography (CT ) images are co-registered and fused with a gadolinium-enhanced T1-weighted MRI where tumor volume and organs at risk are contoured. Alternatively, plain and contrast-enhanced CT scans are co-registered. Single-fraction stereotactic radiotherapy (SRT ) is used to treat patients with good performance status and up to 4 lesions with a diameter of 30 mm or less that are distant from crucial brain function areas. Fractionated SRT (2-5 fractions) is used for larger lesions, in eloquent areas or in proximity to crucial or surgically inaccessible areas and to reduce treatment-related neurotoxicity. The single-fraction SRT dose, which depends on tumor diameter, impacts local control. Fractionated SRT may encompass different schedules. No randomized trial data compared the safety and efficacy of single and multiple fractions. Both single-fraction and fractionated SRT provide satisfactory local control rates, tolerance, a low risk of transient acute adverse events and of radiation necrosis the incidence of which correlated with the irradiated brain volume.

Clinically relevant radioresistant rhabdomyosarcoma cell lines: functional, molecular and immune-related characterization.

BACKGROUND: The probability of local tumor control after radiotherapy (RT) remains still miserably poor in pediatric rhabdomyosarcoma (RMS). Thus, understanding the molecular mechanisms responsible of tumor relapse is essential to identify personalized RT-based strategies. Contrary to what has been done so far, a correct characterization of cellular radioresistance should be performed comparing radioresistant and radiosensitive cells with the same isogenic background. METHODS: Clinically relevant radioresistant (RR) embryonal (RD) and alveolar (RH30) RMS cell lines have been developed by irradiating them with clinical-like hypo-fractionated schedule. RMS-RR cells were compared to parental isogenic counterpart (RMS-PR) and studied following the radiobiological concept of the "6Rs", which stand for repair, redistribution, repopulation, reoxygenation, intrinsic radioresistance and radio-immuno-biology. RESULTS: RMS-RR cell lines, characterized by a more aggressive and in vitro pro-metastatic phenotype, showed a higher ability to i) detoxify from reactive oxygen species; ii) repair DNA damage by differently activating non-homologous end joining and homologous recombination pathways; iii) counteract RT-induced G2/M cell cycle arrest by re-starting growth and repopulating after irradiation; iv) express cancer stem-like profile. Bioinformatic analyses, performed to assess the role of 41 cytokines after RT exposure and their network interactions, suggested TGF-ß, MIF, CCL2, CXCL5, CXCL8 and CXCL12 as master regulators of cancer immune escape in RMS tumors. CONCLUSIONS: These results suggest that RMS could sustain intrinsic and acquire radioresistance by different mechanisms and indicate potential targets for future combined radiosensitizing strategies.

Trehalose inhibits cell proliferation and amplifies long-term temozolomide- and radiation-induced cytotoxicity in melanoma cells: A role for autophagy and premature senescence.

Cutaneous melanomas frequently metastasize to the brain, with temozolomide (TMZ) plus radiotherapy (RT) offering little control of these lesions. We tested whether trehalose, a natural glucose disaccharide proved to induce autophagy, could enhance the effect of TMZ and ionizing radiation (IR). In two melanoma cell lines (A375 and SK-Mel-28), which greatly differ in chemosensitivity and radiosensitivity, trehalose significantly inhibited short-term cell proliferation and also enhanced IR-induced cytostasis. Interestingly, in TMZ-resistant SK-Mel-28 cells, trehalose was more effective than TMZ, and combined trehalose + TMZ further reduced cell proliferation. In long-term experiments, colony-forming capacity was dramatically reduced by trehalose, and even more by combined trehalose + TMZ or trehalose + IR. In resistant SK-Mel-28 cells, although growth was inhibited most with trehalose + TMZ + IR-6 Gy combined treatment, it is notable that trehalose + TMZ treatment was also very effective. Along with a direct antiproliferative effect, two further mechanisms may explain how trehalose potentiates TMZ- and IR-induced effects: the remarkable trehalose-stimulated autophagy in A375 cells, which were sensitive to TMZ- and IR-induced apoptosis; and the notable trehalose-stimulated premature senescence in SK-Mel-28 cells, which were resistant to apoptosis and less prone to autophagy. In normal melanocytes, trehalose induced a minor autophagy and cell proliferation inhibition, without affecting cell viability; moreover, when trehalose was used in combination with TMZ, the slight TMZ-induced cytotoxicity was not significantly reinforced. Together, our results suggest that trehalose, a safe nutrient supplement able to cross the blood-brain barrier, is a promising candidate, worthy to be further explored in vivo, to augment the therapeutic efficacy of TMZ and RT in melanoma brain metastases.

Role of perilesional edema and tumor volume in the prognosis of non-small cell lung cancer (NSCLC) undergoing radiosurgery (SRS) for brain metastases.

AIM: To assess the role of perilesional edema (PE) in non-small cell lung carcinoma (NSCLC) brain metastases (BM) undergoing radiosurgery (SRS). METHODS: This series includes 46 patients with 1-2 BM treated with SRS, selected out of all patients referred for radiotherapy (RT) for BMs over 5 years (2013 to 2017). Both the PE and gross tumor volume (GTV) were contoured on MRI images, and the PE/GTV ratio and PE + GTV value (TV, total volume) were calculated. Our clinical endpoints were brain recurrence free-survival, divided into local brain control (in field, LBC) and distant brain control (out of field, DBC) and overall survival (OS). We analyzed the role of the previously described volumetric parameters and of known clinical prognosticators (disease specific GPA, DS-GPA; chemotherapy, CHT) with Cox regression analyses. RESULTS: Only four patients (9%) developed in-field progression, whereas 10 patients (22%) showed new out-of-field BM and thirty-eight patients died in the follow up (83%). In univariate analysis, both volumetric parameters and clinical parameters were correlated with DBC and OS, whereas we did not find any correlation with LBC. In the multivariate analysis of DBC, the significant parameters were PE/GTV ratio (HR 0.302), sex (HR 0.131), and DS-GPA (HR 0.261). The OS multivariate analysis showed that the only significant parameters were DS-GPA (HR 0.478) and TV (HR: 1.038). CONCLUSION: Our study, although with the limitations of a monocentric retrospective study analyzing a small cohort of patients, suggests the role of PE/GTV ratio for the development of new BMs. TV also seems to be correlated with OS, together with known clinical prognosticators. These findings, if validated in a larger prospective dataset, could help in selecting patients for the most suitable RT modality (or systemic therapy approach).

Texture analysis as a predictor of radiation-induced xerostomia in head and neck patients undergoing IMRT.

PURPOSE: Image texture analysis (TA) is a heterogeneity quantifying approach that cannot be appreciated by the naked eye, and early evidence suggests that TA has great potential in the field of oncology. The aim of this study is to evaluate parotid gland texture analysis (TA) combined with formal dosimetry as a factor for predicting severe late xerostomia in patients undergoing radiation therapy for head and neck cancers. METHODS: We performed a retrospective analysis of patients treated at our Radiation Oncology Unit between January 2010 and December 2015, and selected the patients whose normal dose constraints for the parotid gland (mean dose < 26 Gy for the bilateral gland) could not be satisfied due to the presence of positive nodes close to the parotid glands. The parotid gland that showed the higher V30 was contoured on CT simulation and analysed with LifeX Software©. TA parameters included features of grey-level co-occurrence matrix (GLCM), neighbourhood grey-level dependence matrix (NGLDM), grey-level run length matrix (GLRLM), grey-level zone length matrix (GLZLM), sphericity, and indices from the grey-level histogram. We performed a univariate and multivariate analysis between all the texture parameters, the volume of the gland, the normal dose parameters (V30 and Mean Dose), and the development of severe chronic xerostomia. RESULTS: Seventy-eight patients were included and 25 (31%) developed chronic xerostomia. The TA parameters correlated with severe chronic xerostomia included V30 (OR 5.63), Dmean (OR 5.71), Kurtosis (OR 0.78), GLCM Correlation (OR 1.34), and RLNU (OR 2.12). The multivariate logistic regression showed a significant correlation between V30 (0.001), GLCM correlation (p: 0.026), RLNU (p: 0.011), and chronic xerostomia (p < 0.001, R2:0.664). CONCLUSIONS: Xerostomia represents an important cause of morbidity for head and neck cancer survivors after radiation therapy, and in certain cases normal dose constraints cannot be satisfied. Our results seem promising as texture analysis could enhance the normal dose constraints for the prediction of xerostomia.

Perilesional edema in brain metastasis from non-small cell lung cancer (NSCLC) as predictor of response to radiosurgery (SRS).

Radiosurgery (SRS) is widely used in the treatment of brain oligo-metastases from NSCLC. The aim of present study is to evaluate the extent of perilesional edema in brain metastases as predictive factor of treatment response. This single center retrospective study included 42 consecutive patients (January 2011-December 2014) with 1-2 brain metastasis from NSCLC treated with Radiosurgery (SRS). Extent of perilesional edema was measured as maximal extension from the edge of lesion and classified as minor (<10 mm) or major (≥10 mm). We analyzed Modality of Brain Recurrence (MBR), classified as in-field or out-of- field, and Brain Progression Free-Survival (BPFS) after treatment stratified according to extent of perilesional edema. Analyzing modality of brain recurrence and BPFS, after a median follow-up of 6 months, we found that patients with minor edema had a better radiological response to SRS with none in-field recurrences and a lower risk of the onset of new brain lesions (out-of-field recurrence). Instead, patients group with major edema had a worse response rate of lesions treated, further, a higher risk of out-of-field brain relapse. Extent of perilesional edema in brain metastasis from NSCLC could be a predictive factor of response and brain progression after SRS treatment alone.

Combined EGFR and autophagy modulation impairs cell migration and enhances radiosensitivity in human glioblastoma cells.

Glioblastoma (GBM) remains the most aggressive and lethal brain tumor due to its molecular heterogeneity and high motility and invasion capabilities of its cells, resulting in high resistance to current standard treatments (surgery, followed by ionizing radiation combined with Temozolomide chemotherapy administration). Locus amplification, gene overexpression, and genetic mutations of epidermal growth factor receptor (EGFR) are hallmarks of GBM that can ectopically activate downstream signaling oncogenic cascades such as PI3K/Akt/mTOR pathway. Importantly, alteration of this pathway, involved also in the regulation of autophagy process, can improve radioresistance in GBM cells, thus promoting the aggressive phenotype of this tumor. In this work, the endogenous EGFR expression profile and autophagy were modulated to increase radiosensitivity behavior of human T98G and U373MG GBM cells. Our results primarily indicated that EGFR interfering induced radiosensitivity according to a decrease of the clonogenic capability of the investigated cells, and an effective reduction of the in vitro migratory features. Moreover, EGFR interfering resulted in an increase of Temozolomide (TMZ) cytotoxicity in T98G TMZ-resistant cells. In order to elucidate the involvement of the autophagy process as pro-death or pro-survival role in cells subjected to EGFR interfering, the key autophagic gene ATG7 was silenced, thereby producing a transient block of the autophagy process. This autophagy inhibition rescued clonogenic capability of irradiated and EGFR-silenced T98G cells, suggesting a pro-death autophagy contribution. To further confirm the functional interplay between EGFR and autophagy pathways, Rapamycin-mediated autophagy induction during EGFR modulation promoted further impairment of irradiated cells, in terms of clonogenic and migration capabilities. Taken together, these results might suggest a novel combined EGFR-autophagy modulation strategy, to overcome intrinsic GBM radioresistance, thus improving the efficacy of standard treatments. J. Cell. Physiol. 229: 1863-1873, 2014. © 2014 Wiley Periodicals, Inc.

Clinical radiobiology of glioblastoma multiforme: estimation of tumor control probability from various radiotherapy fractionation schemes.

BACKGROUND AND PURPOSE: The aim of this study was to estimate a radiobiological set of parameters from the available clinical data on glioblastoma (GB). PATIENTS AND METHODS: A number of clinical trial outcomes from patients affected by GB and treated with surgery and adjuvant radiochemotherapy were analyzed to estimate a set of radiobiological parameters for a tumor control probability (TCP) model. The analytical/graphical method employed to fit the clinical data allowed us to estimate the intrinsic tumor radiosensitivity (α), repair capability (b), and repopulation doubling time (T d ) in a first phase, and subsequently the number of clonogens (N) and kick-off time for accelerated proliferation (T(k)). The results were used to formulate a hypothesis for a schedule expected to significantly improve local control. The 95 % confidence intervals (CI(95 %)) of all parameters are also discussed. RESULTS: The pooled analysis employed to estimate the parameters summarizes the data of 559 patients, while the studies selected to verify the results summarize data of 104 patients. The best estimates and the CI(95 %) are α = 0.12 Gy⁻¹ (0.10-0.14), b = 0.015 Gy⁻² (0.013-0.020), α/b = 8 Gy (5.0-10.8), T(d) = 15.4 days (13.2-19.5), N = 1.104(1.2.10³ - 1.105), and T(k) = 37 days (29-46). The dose required to offset the repopulation occurring after 1 day (D(prolif)) and starting after T k was estimated as 0.30 Gy/day (0.22-0.39). CONCLUSION: The analysis confirms a high value for the α/b ratio. Moreover, a high intrinsic radiosensitivity together with a long kick-off time for accelerated repopulation and moderate repopulation kinetics were found. The results indicate a substantial independence of the duration of the overall treatment and an improvement in the treatment effectiveness by increasing the total dose without increasing the dose fraction.

Current status and perspectives of interventional clinical trials for brain metastases: analysis of ClinicalTrials.gov.

BACKGROUND: The management of brain metastases (BM), the major cause of cancer morbidity and mortality, is becoming an emerging area of interest. Surgery, whole brain radiation therapy (WBRT), or stereotactic radiosurgery (SRS), have historically been the main focal treatments for BM. However, the introduction of innovative targeted- and immune-based therapies is progressively changing the paradigm of BM treatment, resulting in an increase in clinical trials investigating new therapeutic strategies. METHODS: Using ClinicalTrials.gov, the largest clinical trial registry with over 400,000 registered trials, we performed an analysis of phase II and phase III ongoing trials evaluating different systemic therapies, radiotherapy (RT), and surgery given alone or in combination in patients with BM. RESULTS: One hundred sixty-eight trials, 133 phase II and 35 phase III; the largest part having primarily the curative treatment of patients with BM from lung cancer, breast cancer and melanoma, were selected. One hundred sixty-three trials used systemic therapies. One hundred thirteen used tyrosine kinase inhibitors, more frequently Osimertinib, Icotinib and Pyrotinib, 50 used monoclonal antibodies, more frequently Trastuzumab, Pembrolizumab, Nivolumab, 20 used conventional chemotherapies whilst no oncological active drugs were used in 6 trials. Ninety-six trials include RT; 54 as exclusive treatment and 42 in combination with systemic therapies. CONCLUSION: Systemic targeted- and/or immune-based therapies, combined or not with RT, are increasingly used in the routine of BM treatment. SRS is progressively replacing WBRT. All these trials intend to address multiple questions on the management of patients with BMs, including the recommended upfront treatment for different cancer histologies and the optimal timing between systemic therapies and radiation regarding brain control and neurocognitive outcome and quality of life.

Feasibility of clinical target volume reduction for glioblastoma treated with standard chemoradiation based on patterns of failure analysis.

PURPOSE: To analyze recurrence patterns in patients with glioblastoma (GBM) after standard chemoradiation according to different target volume delineation strategies. METHODS AND MATERIALS: Two hundred seven patients with GBM who recurred after standard chemoradiation were evaluated. According to ESTRO target volume delineation guideline, the CTV was generated by adding a 2-cm margin to the GTV, defined as the resection cavity plus residual tumor. Patterns of failure were analyzed using dose-volume histogram. Recurrent lesions were defined as in-field, marginal, or distant if > 80 %, 20-80 %, or < 20 % of the intersecting volume was included in the 95 % isodose line.For each patient, a theoretical plan consisting of reduced 1-cm GTV-to-CTV margin was created to compare patterns of failure and radiation doses to normal brain. RESULTS: Median overall survival and progression-free survival times were 15.3 months and 7.8 months, respectively, from the date of surgery. Recurrences were in-field in 180, marginal in 5, and distant in 22 patients. According to MGMT promoter methylation, distant recurrences occurred in 18.6 % of methylated and 6 % of unmethylated tumors (p = 0.0046). Following replanning with 1-cm reduced margin, dosimetric analysis showed similar patterns of failure. Recurrences were in-field, marginal, and distant in 177, 3, and 27 plans, respectively, although radiation doses to the healthy brain and hippocampi were significantly lower compared with standard target delineation (p = 0.0001). CONCLUSION: Current provide the rationale for evaluating GTV-to-CTV margin reduction in future clinical trials with the aim of limiting the cognitive sequelae of GBM irradiation while maintaining survival benefits of standard chemoradiation.

Abscopal Effect on Bone Metastases from Solid Tumors: A Systematic Review and Retrospective Analysis of Challenge within a Challenge.

BACKGROUND: Abscopal effect (AE) describes the ability of radiotherapy (RT) to induce immune-mediated responses in nonirradiated distant metastasis. Bone represents the third most frequent site of metastasis and an immunologically favorable environment for the proliferation of cancer cells. We revised the literature, searching documented cases of AE involving bone metastases (BMs) and evaluated the incidence of AE involving BMs in patients requiring palliative RT on BMs or non-BMs treated at our department. METHODS: Articles published in the PubMed/MEDLINE database were selected using the following search criteria: ((abscopal effect)) AND ((metastases)). Patients with BMs, who underwent performed bone scintigraphy before and at least 2-3 months after RT, were selected and screened between January 2015 and July 2022. AE was defined as an objective response according to the scan bone index for at least one nonirradiated metastasis at a distance > 10 cm from the irradiated lesion. The primary endpoint was the rate of AE on BMs. RESULTS: Ten cases experiencing AE of BMs were identified from the literature and eight among our patients. CONCLUSIONS: The analysis performed here suggests the use of hypofractionated radiotherapy as the only triggering factor for AE of BMs through the activation of the immune response.

Different involvement of autophagy in human malignant glioma cell lines undergoing irradiation and temozolomide combined treatments.

Glioblastoma (GB) has a poor prognosis, despite current multimodality treatment. Beside surgical resection, adjuvant ionizing radiation (IR) combined with Temozolomide (TMZ) drug administration is the standard therapy for GB. This currently combined radio-chemotherapy treatment resulted in glial tumor cell death induction, whose main molecular death pathways are still not completely deciphered. In this study, the autophagy process was investigated, and in vitro modulated, in two different GB cell lines, T98G and U373MG (known to differ in their radiosensitivity), after IR or combined IR/TMZ treatments. T98G cells showed a high radiosensitivity (especially at low and intermediate doses), associated with autophagy activation, assessed by Beclin-1 and Atg-5 expression increase, LC3-I to LC3-II conversion and LC3B-GFP accumulation in autophagosomes of irradiated cells; differently, U373MG cells resulted less radiosensitive. Autophagy inhibition, using siRNA against BECN1 or ATG-7 genes, totally prevented decrease in viability after both IR and IR/TMZ treatments in the radiosensitive T98G cells, confirming the autophagy involvement in the cytotoxicity of these cells after the current GB treatment, contrary to U373MG cells. However, rapamycin-mediated autophagy, that further radiosensitized T98G, was able to promote radiosensitivty also in U373MG cells, suggesting a role of autophagy process in enhancing radiosensitivity. Taken together, these results might enforce the concept that autophagy-associated cell death might constitute a possible adjuvant therapeutic strategy to enhance the conventional GB treatment.

Single-isocenter multiple-target stereotactic radiosurgery for multiple brain metastases: dosimetric evaluation of two automated treatment planning systems.

PURPOSE: Automated treatment planning systems are available for linear accelerator (linac)-based single-isocenter multi-target (SIMT) stereotactic radiosurgery (SRS) of brain metastases. In this study, we compared plan quality between Brainlab Elements Multiple Brain Metastases (Elements MBM) software which utilizes dynamic conformal arc therapy (DCAT) and Varian HyperArc (HA) software using a volumetric modulated arc therapy (VMAT) technique. PATIENTS AND METHODS: Between July 2018 and April 2021, 36 consecutive patients ≥ 18 years old with 367 metastases who received SIMT SRS at UPMC Hillman Cancer San Pietro Hospital, Rome, were retrospectively evaluated. SRS plans were created using the commercial software Elements MBM SRS (Version 1.5 and 2.0). Median cumulative gross tumor volume (GTV) and planning tumor volume (PTV) were 1.33 cm3 and 3.42 cm3, respectively. All patients were replanned using HA automated software. Extracted dosimetric parameters included mean dose (Dmean) to the healthy brain, volumes of the healthy brain receiving more than 5, 8,10, and 12 Gy (V5Gy, V8Gy, V10Gy and V12Gy), and doses to hippocampi. RESULTS: Both techniques resulted in high-quality treatment plans, although Element MBM DCAT plans performed significantly better than HA VMAT plans, especially in cases of more than 10 lesions). Median V12Gy was 13.6 (range, 1.87-45.9) cm3 for DCAT plans and 18.5 (2.2-62,3) cm3 for VMAT plans (p < 0.0001), respectively. Similarly, V10Gy, V8Gy, V5Gy (p < 0.0001) and median dose to the normal brain (p = 0.0001) were favorable for DCAT plans. CONCLUSIONS: Both Elements MBM and HA systems were able to generate high-quality plans in patients with up to 25 brain metastases. DCAT plans performed better in terms of normal brain sparing, especially in patients with more than ten lesions and limited total tumor volume.

Stereotactic radiosurgery for the treatment of brainstem metastases: a multicenter retrospective study.

BACKGROUND: Brainstem metastases (BSM) are associated with a poor prognosis and their management represents a therapeutic challenge. BSM are often inoperable and, in absence of randomized trials, the optimal radiation treatment of BSM remains to be defined. We evaluated the efficacy and toxicity of linear accelerator (linac)-based stereotactic radiosurgery (SRS) and hypofractionated steretotactic radiotherapy (HSRT) in the treatment of BSM in a series of patients treated in different clinical centers. METHODS: We conducted a multicentric retrospective study of patients affected by 1-2 BSM from different histologies who underwent SRS/HSRT. Freedom from local progression (FLP), cancer-specific survival (CSS), overall survival (OS), and treatment-related toxicity were evaluated. In addition, predictors of treatment response and survivals were evaluated. RESULTS: Between 2008 and 2021, 105 consecutive patients with 111 BMS who received SRS or HSRT for 1-2 BSM were evaluated. Median follow-up time was 10 months (range 3-130). One-year FLP rate was 90.4%. At the univariate analysis, tumor volume ≤ 0.4 cc, and concurrent targeted therapy were associated with longer FLP, with combined treatment that remained a significant independent predictor [0.058, HR 0.139 (95% CI 0.0182-1.064]. Median OS and CSS were 11 months and 14.6 months, respectively. At multivariate analysis, concurrent targeted therapy administration was significantly associated with longer OS [HR 0.514 (95%CI 0.302-0.875); p = 0.01]. Neurological death occurred in 30.4% of patients, although this was due to local progression in only 3 (2.8%) patients. CONCLUSION: Linac-based SRS/HSRT offers excellent local control to patients with BSM, with low treatment-related toxicity and no apparent detrimental effects on OS. When treated with ablative intent, BSM are an uncommon cause of neurological death. The present results indicates that patients with BSM should not be excluded a priori from clinical trials.