Radiobiology and radiotherapy of brain metastases

Neuroprotective effects of saxagliptin against radiation-induced cognitive impairment: Insights on Akt/CREB/SIRT1/BDNF signaling pathway

Radiation-induced cognitive impairment has recently fueled scientific interest with an increasing prevalence of cancer patients requiring whole brain irradiation (WBI) in their treatment algorithm. Saxagliptin (SAXA), a dipeptidyl peptidase-IV (DPP-IV) inhibitor, has exhibited competent neuroprotective effects against varied neurodegenerative disorders. Hence, this study aimed at examining the efficacy of SAXA in alleviating WBI-induced cognitive deficits. Male Sprague Dawley rats were distributed into control group, WBI group exposed to 20 Gy ϒ-radiation, SAXA group treated for three weeks with SAXA (10 mg/kg. orally, once daily), and WBI/SAXA group exposed to 20 Gy ϒ-radiation then treated with SAXA (10 mg/kg. orally, once daily). SAXA effectively reversed memory deterioration and motor dysfunction induced by 20 Gy WBI during behavioural tests and preserved normal histological architecture of the hippocampal tissues of irradiated rats. Mechanistically, SAXA inhibited WBI-induced hippocampal oxidative stress via decreasing lipid peroxidation while restoring catalase antioxidant activity. Moreover, SAXA abrogated radiation-induced hippocampal neuronal apoptosis through downregulating proapoptotic Bcl-2 Associated X-protein (Bax) and upregulating antiapoptotic B-cell lymphoma 2 (Bcl-2) expressions and eventually diminishing expression of cleaved caspase 3. Furthermore, SAXA boosted hippocampal neurogenesis by upregulating brain-derived neurotrophic factor (BDNF) expression. These valuable neuroprotective capabilities of SAXA were linked to activating protein kinase B (Akt), and cAMP-response element-binding protein (CREB) along with elevating the expression of sirtuin 1 (SIRT-1). SAXA successfully mitigated cognitive dysfunction triggered by WBI, attenuated oxidative injury, and neuronal apoptosis, and enhanced neurogenesis through switching on Akt/CREB/BDNF/SIRT-1 signaling axes. Such fruitful neurorestorative effects of SAXA provide an innovative therapeutic strategy for improving the cognitive capacity of cancer patients exposed to radiotherapy.

The importance of integrated therapies on cancer: Silibinin, an old and new molecule

In the landscape of cancer treatments, the efficacy of coadjuvant molecules remains a focus of attention for clinical research with the aim of reducing toxicity and achieving better outcomes. Most of the pathogenetic processes causing tumour development, neoplastic progression, ageing, and increased toxicity involve inflammation. Inflammatory mechanisms can progress through a variety of molecular patterns. As is well known, the ageing process is determined by pathological pathways very similar and often parallel to those that cause cancer development. Among these complex mechanisms, inflammation is currently much studied and is often referred to in the geriatric field as 'inflammaging'. In this context, treatments active in the management of inflammatory mechanisms could play a role as adjuvants to standard therapies. Among these emerging molecules, Silibinin has demonstrated its anti-inflammatory properties in different neoplastic types, also in combination with chemotherapeutic agents. Moreover, this molecule could represent a breakthrough in the management of age-related processes. Thus, Silibinin could be a valuable adjuvant to reduce drug-related toxicity and increase therapeutic potential. For this reason, the main aim of this review is to collect and analyse data presented in the literature on the use of Silibinin, to better understand the mechanisms of the functioning of this molecule and its possible therapeutic role.

Short-term predictors of stereotactic radiosurgery outcome for untreated single non-small cell lung cancer brain metastases: a restrospective cohort study

Stereotactic radiosurgery (SRS) is an option for brain metastases (BM) not eligible for surgical resection, however, predictors of SRS outcomes are poorly known. The aim of this study is to investigate predictors of SRS outcome in patients with BM secondary to non-small cell lung cancer (NSCLC). The secondary objective is to analyze the value of volumetric criteria in identifying BM progression. This retrospective cohort study included patients >18 years of age with a single untreated BM secondary to NSCLC. Demographic, clinical, and radiological data were assessed. The primary outcome was treatment failure, defined as a BM volumetric increase 12 months after SRS. The unidimensional measurement of the BM at follow-up was also assessed. One hundred thirty-five patients were included, with a median BM volume at baseline of 1.1 cm3 (IQR 0.4-2.3). Fifty-two (38.5%) patients had SRS failure at follow-up. Only right BM laterality was associated with SRS failure (p=0.039). Using the volumetric definition of SRS failure, the unidimensional criteria demonstrated a sensibility of 60.78% (46.11%-74.16%), specificity of 89.02% (80.18%-94.86%), positive LR of 5.54 (2.88-10.66) and negative LR of 0.44 (0.31-0.63). SRS demonstrated a 61.5% local control rate 12 months after treatment. Among the potential predictors of treatment outcome analyzed, only the right BM laterality had a significant association with SRS failure. The volumetric criteria were able to identify more subtle signs of BM increase than the unidimensional criteria, which may allow earlier diagnosis of disease progression and use of appropriate therapies.

Predictors of Survival After Stereotactic Radiosurgery for Untreated Single Non-Small Cell Lung Cancer Brain Metastases: 5- and 10-year Results

BACKGROUND

Stereotactic radiosurgery (SRS) presents as a good treatment option for smaller, deep-seated brain metastases (BMs). This study aims to determine predictors of SRS failure for patients with non-small cell lung cancer BMs.

METHODS

This was a retrospective study of single non-small cell lung cancer BMs treated using SRS. We included patients >18 years with a single, previously untreated lesion. Primary outcome was treatment failure, defined as BMs dimension increase above the initial values. Demographic, clinical, and radiological data were collected to study potential predictors of treatment failure.

RESULTS

Worse rates of progression-free survival (PFS) were associated with heterogeneous contrast enhancement (18.1 ± 4.1 vs. 41.9 ± 4 months; P < 0.001). Better rates of PFS were associated with volumes <1.06 cm3 (log-rank; P = 0.001). Graded prognostic assessment was significantly associated with survival at 120 months (log-rank; P < 0.001). Karnofsky Performance Scale was evaluated in 3 strata: 90-100, 80, and ≤70. Mean survival rates for these strata were 31.8 ± 3.9, 10.6 ± 2.2, and 9.8 ± 2.3 months, respectively (log-rank; P < 0.001). There were no differences regarding presence of extracranial metastases, age, or lesion location. A multivariable logistic regression found that volume <1.06 cm3 was associated with higher survival rates at 10 years (odds ratio: 3.2, 95% confidence interval: 1.3-8.0).

CONCLUSIONS

Contrast-homogeneous metastases and lesions <1.06 cm3 are associated with better rates of PFS. Karnofsky Performance Scale and graded prognostic assessment were associated with more favorable survival rates after 10 years. Volume <1.06 cm3 was the only significant predictor of survival in the multivariable analysis.

Rodent Model of Brain Radionecrosis using Clinical LINAC-based Stereotactic Radiosurgery

Purpose

Methods and Materials

Results

Conclusions

Transient Enlargement in Meningiomas Treated with Stereotactic Radiotherapy

Simple Summary

Accurate assessment of treatment efficacy is a prerequisite for the improvement in therapeutic outcomes in clinical trials. However, it is very challenging to accurately track the size of meningiomas after radiotherapy, because of their complex shapes and often slow growth. Measuring the whole tumor volume as opposed to simple diameter measurements to assess treatment efficacy, therefore, is very promising but little is known on expected volumetric changes of meningiomas following radiotherapy. Therefore, in this study, we meticulously investigated volumetric changes in meningiomas following radiotherapy incorporating volumetric measurements from 468 MRI studies and evaluated newly proposed RANO volumetric criteria in the context of radiotherapy. We found that temporary tumor enlargement after radiotherapy overall was rare but occurred significantly more frequently after high than after low single doses of radiation, represented an important differential diagnosis to tumor progression and would have skewed results in a clinical trial if not accounted for.

Abstract

To investigate the occurrence of pseudoprogression/transient enlargement in meningiomas after stereotactic radiotherapy (RT) and to evaluate recently proposed volumetric RANO meningioma criteria for response assessment in the context of RT. Sixty-nine meningiomas (benign: 90%, atypical: 10%) received stereotactic RT from January 2005–May 2018. A total of 468 MRI studies were segmented longitudinally during a median follow-up of 42.3 months. Best response and local control were evaluated according to recently proposed volumetric RANO criteria. Transient enlargement was defined as volumetric increase ≥20% followed by a subsequent regression ≥20%. The mean best volumetric response was −23% change from baseline (range, −86% to +19%). According to RANO, the best volumetric response was SD in 81% (56/69), MR in 13% (9/69) and PR in 6% (4/69). Transient enlargement occurred in only 6% (4/69) post RT but would have represented 60% (3/5) of cases with progressive disease if not accounted for. Transient enlargement was characterized by a mean maximum volumetric increase of +181% (range, +24% to +389 %) with all cases occurring in the first year post-RT (range, 4.1–10.3 months). Transient enlargement was significantly more frequent with SRS or hypofractionation than with conventional fractionation (25% vs. 2%, p = 0.015). Five-year volumetric control was 97.8% if transient enlargement was recognized but 92.9% if not accounted for. Transient enlargement/pseudoprogression in the first year following SRS and hypofractionated RT represents an important differential diagnosis, especially because of the high volumetric control achieved with stereotactic RT. Meningioma enlargement during subsequent post-RT follow-up and after conventional fractionation should raise suspicion for tumor progression.

The Effect of Hippocampal Avoidance Whole Brain Radiotherapy on the Preservation of Long-Term Neurocognitive Function in Non-Small Cell Lung Cancer Patients With Brain Metastasis

Whole-brain radiotherapy (WBRT) is the mainstay of therapy in treating cancer patients with brain metastases, but unfortunately, it might also lead to decline in neurocognitive function. This study aims to investigate the preservation of long-term neurocognitive function in patients after hippocampal avoidance whole-brain radiotherapy (HA-WBRT). Retrospectively, 47 patients diagnosed with brain metastases of non-small cell lung cancer (NSCLC) between 2015-01-01 and 2017-12-31 at the Department of Oncology, XXX Hospital were selected and divided into 2 groups. Group A (n = 27) received HA-WBRT, whereas group B (n = 20) received WBRT. Neurocognitive function was analyzed at baseline and at 3, 6, 9, 12 and 24 months after radiotherapy, using Mine-Mental State Examination (MMSE) scales and Montreal Cognitive Assessment (MoCA) scales. The OS, PFS and tumor recurrence sites were also analyzed. When evaluated at 12 and 24 months after radiotherapy, the cognitive function scores of the hippocampal avoidance group were significantly higher than those of the non-hippocampal avoidance group (P < 0.001). In terms of patient survival, there was no significant difference in OS (P = 0.2) and PFS (P = 0.18) between these 2 groups. Fourteen patients in group A and 12 patients in group B had brain tumor recurrence after radiation, only one patient in group A occurred within 5 mm from the edge of the hippocampus (P > 0.05). In conclusion, HA-WBRT might have a protective effect on long-term neurocognitive function and did not affect patient survival.

MRI Detection of Changes in Tissue Sodium Concentration in Brain Metastases after Stereotactic Radiosurgery: A Feasibility Study

BACKGROUND AND PURPOSE

To date, treatment response to stereotactic radiosurgery (SRS) in brain metastases (BM) can only be determined by MRI evaluation of contrast-enhancing lesions in a long-time follow-up. Sodium MRI has been a subject of immense interest in imaging research as the measure of tissue sodium concentration (TSC) can give valuable quantitative information on cell viability. We aimed to analyze the longitudinal changes of TSC in BM measured with ²³ Na MRI before and after SRS for assessment of early local tumor effects.

METHODS

Seven patients with a total of 12 previously untreated BM underwent SRS with 22 Gy. In addition to a standard MRI protocol including dynamic susceptibility-weighted contrast-enhanced perfusion, a ²³ Na MRI was performed at three time points: (I) 2 days before, (II) 5 days, and (III) 40 days after SRS. Nine BMs were evaluated. The absolute TSC in the BM, the respective peritumoral edemas, and the normal-appearing corresponding contralateral brain area were assessed and the relative TSC were correlated to the changes in BM longest axial diameters.

RESULTS

TSC was elevated in nine BM at baseline before SRS with a mean of 73.4 ± 12.3 mM. A further increase in TSC was observed 5 days after SRS in all the nine BM with a mean of 86.9 ± 13 mM. Eight of nine BM showed a mean 60.6 ± 13.3% decrease in the longest axial diameter 40 days after SRS; at this time point, the TSC also had decreased to a mean 65.1 ± 7.9 mM. In contrast, one of the nine BM had a 13.4% increase in the largest axial diameter at time point III. The TSC of this BM showed a further TSC increase of 80.1 mM 40 days after SRS.

CONCLUSION

Changes in TSC using ²³ Na MRI shows the possible capability to detect radiobiological changes in BM after SRS.

A graded prognostic model for patients surviving 3 years or more (GPM ≥ 3Ys) after stereotactic radiosurgery for brain metastasis

BACKGROUND AND PURPOSE

As more cancer patients with brain metastases (BMs) are surviving longer due to recent advancements in various treatment modalities, we developed a grading system for stereotactic radiosurgery (SRS)-treated BM patients with long survival. This is a Graded Prognostic Model for Patients Surviving 3 Years or More (GPM ≥ 3Ys).

MATERIALS AND METHODS

First, using clinical factor-survival time analysis of 3237 patients in whom gamma knife (GK) SRS was performed by the second author (test cohort), we developed the GPM ≥ 3Ys based on survival ≥3 years as the objective variable. The validity of this model was then tested using another series of 3317 patients independently undergoing GK SRS performed by the third author (verification cohort). Number of patients surviving 3 years or more were 289 (8.9%) and 348 (10.5%), respectively.

RESULTS

Using the test series, among various pre-SRS clinical factors, noted below, five were shown to be highly correlated with survival of ≥3 years. Therefore, we assigned scores for these five factors, i.e., "tumor numbers 1/2-4/≥5 (score; 6/1/0)", "female/male (5/0)", "KPS ≥80%/<80% (5/0)", "primary cancers of breast/lung/gastrointestinal tract/other (score; 1/0/3/0)", "controlled primary cancer/not (8/0)" and "existing extra-cerebral metastases/not (5/0). Patients were categorized into four grades according to the sum of scores, i.e., 0-9, 10-19, 20-29 and 30-36. Post-SRS mean survival times (MSTs) differed significantly (p < 0.0001) with no overlapping of 95% confidence intervals (CIs) among the four grades. Also, in the verification series, MSTs differed significantly (p < 0.0001) with no overlapping of 95% CI among the four grades of the GPM ≥ 3Ys system.

CONCLUSION

Although this was a retrospective study, the GPM ≥ 3Ys system was shown to be very useful to physicians selecting among more aggressive treatment modalities for patients in whom longer survival can be expected.

FSRT vs. SRS in Brain Metastases-Differences in Local Control and Radiation Necrosis-A Volumetric Study

Background: While the role of stereotactic radiotherapy for brain metastases is increasing, evidence on the comparative efficacy and safety of fractionated stereotactic radiotherapy (FSRT) and single-session radiosurgery (SRS) is scarce.

Methods: Longitudinal volumetric analysis was performed in a consecutive cohort of 120 patients and 190 brain metastases (>0.065 cm³ in volume / > ~5 mm in diameter) treated exclusively with FSRT (n = 98) and SRS (n = 92), respectively. A total of 972 tumor segmentations was used, averaging 5.1 time points per metastasis. Progression was defined using a volumetric extension of the RANO-BM criteria. Local control and radionecrosis were compared for lesions treated with FSRT and SRS, respectively.

Results: Metastases treated with FSRT were significantly larger at baseline (mean, 4.66 vs. 0.40 cm³, p < 0.001). Biologically effective dose (BED) for metastases (α/β = 12, linear-quadratic-cubic model) was significantly associated with local control, whereas BED for normal brain (α/β = 2, linear-quadratic model) was significantly associated with radionecrosis. Median time to local progression was 22.9 months in the FSRT group compared to 14.5 months in the SRS group (p = 0.022). Overall radionecrosis rate at 12 months was 3.4% for FSRT and 14.8% for SRS (p = 0.010). Radionecrosis °IV requiring resection with histologic proof of radiation necrosis also was significantly reduced in the FSRT group (FSRT 0.0% vs. SRS 3.9%, p = 0.041). In multivariate analysis, FSRT was associated with reduced risk of progression (HR 0.47, p = 0.015) and reduced risk of radionecrosis (HR 0.18, p = 0.045).

Conclusions: This volumetric study provides initial evidence that the improvements in therapeutic ratio expected for FSRT in larger brain metastases, might equally extend into the domain of smaller metastases, traditionally less considered for fractionated treatment. FSRT might constitute an important tool to further increase local control and reduce radionecrosis risk in stereotactic radiotherapy for brain metastases, that should be assessed in randomized intervention trials.

Ionizing Radiation as a Source of Oxidative Stress-The Protective Role of Melatonin and Vitamin D

Ionizing radiation (IR) has found widespread application in modern medicine, including medical imaging and radiotherapy. As a result, both patients and healthcare professionals are exposed to various IR doses. To minimize the negative side effects of radiation associated with oxidative imbalance, antioxidant therapy has been considered. In this review, studies on the effects of melatonin and vitamin D on radiation-induced oxidative stress are discussed. According to the research data, both substances meet the conditions for use as agents that protect humans against IR-induced tissue damage. Numerous studies have confirmed that melatonin, a hydro- and lipophilic hormone with strong antioxidant properties, can potentially be used as a radioprotectant in humans. Less is known about the radioprotective effects of vitamin D, but the results to date have been promising. Deficiencies in melatonin and vitamin D are common in modern societies and may contribute to the severity of adverse side effects of medical IR exposure. Hence, supporting supplementation with both substances seems to be of first importance. Interestingly, both melatonin and vitamin D have been found to selectively radiosensitise cancer cells, which makes them promising adjuvants in radiotherapy. More research is needed in this area, especially in humans.

Stereotactic irradiation of non-small cell lung cancer brain metastases: evaluation of local and cerebral control in a large series

Stereotactic radiotherapy (SRT) of brain metastases (BM) results are often reported in the heterogeneous primitive population. Here, we report our experience in consecutively treated patients who underwent SRT alone for BM from non-small cell lung cancer (NSCLC). This retrospective analysis included consecutive patients with no history of cerebral treatment who underwent Cyberknife™ SRT for BM from NSCLC in our institution from 2007 to 2016. One hundred patients were included in the study, with a median follow-up of 33 months (20-64). Mean age was 63 years (SD ± 10); 88% had Karnofsky Performance Status (KPS) > 70; 67% had unique BM; 18 patients received single-fraction SRT (20-25 Gy), and 82 received hypo-fractionated SRT (HSRT) (24-36 Gy in 3-5 fractions). We reported a complication rate of 17% (2% of G3-4). Median survival was 10.1 months [95% confidence interval (CI) 7.8-13.9]. At 1 year, local and cerebral control rates were respectively 78.7% (95% CI 70-86.5%) and 43% (95% CI 33.5-53%). Thirty patients underwent salvage treatment (whole brain radiation therapy, n = 13; SRT, n = 14; surgery, n = 3). Cyberknife™-based SRT is an effective treatment associated with high local control rate with low morbidity for patients with NSCLC's BM. Close follow-up is necessary to perform salvage treatment.

Long-term survival results after treatment for oligometastatic brain disease

Aim

The aim of this study was to characterize the survival results of patients with up to four brain metastases after intense local therapy (primary surgery or stereotactic radiotherapy) if extracranial metastases were absent or limited to one site, e.g. the lungs.

Background

Oligometastatic disease has repeatedly been reported to convey a favorable prognosis.

Material and methods

This retrospective study included 198 German and Norwegian patients treated with individualized approaches, always including brain radiotherapy. Information about age, extracranial spread, number of brain metastases, performance status and other variables was collected. Uni- and multivariate tests were performed.

Results

Median survival was 16.5 months (single brain metastasis) and 9.8 months (2-4, comparable survival for 2, 3 and 4), respectively (p = 0.001). After 5 years, 15 and 2% of the patients were still alive. In patients alive after 2 years, added median survival was 23 months and the probability of being alive 5 years after treatment was 26%. In multivariate analysis, extracranial metastases were not significantly associated with survival, while primary tumor control was.

Conclusion

Long-term survival beyond 5 years is possible in a minority of patients with oligometastatic brain disease, in particular those with a single brain metastasis. The presence of extracranial metastases to one site should not be regarded a barrier towards maximum brain-directed therapy.

Factors associated with long-term survival in central nervous system metastases

BACKGROUND

Cancer is a leading cause of death worldwide; central nervous system metastases (CNSm) are amongst the most common complications of cancer and are associated with high morbidity and mortality. The aim of the study was to associate clinic and oncologic characteristics with the possibility of survival for ≥ 1 year.

MATERIALS AND METHODS

A prospective cohort in two referral centers recollected clinical and oncologic data from patients diagnosed with CNSm. Chronic metastases were defined as those patients that survived for ≥ 12 months after the diagnosis of CNSm.

RESULTS

Of 613 patients with CNSm, 554 had solid tumors as the primary cancer and were included; 405 (73%) were women, the most common primary cancer site were breast, lung and urologic. Chronic CNSm were found in 260 (47%) and were compared to those who did not. After multivariate logistic regression analysis, variables associated with good prognosis (living > 12 months) were: female sex (HR 0.55), single CNSm (HR 0.39), diagnosis of CNSm during initial extension studies or during presentation of cancer (HR 0.43), and occipital location (HR 0.62).

CONCLUSIONS

Long-term survival in patients with CNSm remains a topic of debate; their bad prognosis could be changing towards improvement. Clinical findings are typically overlooked in CNSm reports and prognostic scales. After our findings, we propose to include them in forthcoming studies to aid prognostic considerations. Factors associated with prolonged survival found in our study include female gender, timing of CNSm diagnosis, occipital lobe location, and single CNSm.