Prophylactic cranial irradiation for patients with lung cancer

Predicting overall survival and prophylactic cranial irradiation benefit in small-cell lung cancer with CT-based deep learning: A retrospective multicenter study

BACKGROUND AND PURPOSE

To develop a computed tomography (CT)-based deep learning model to predict overall survival (OS) among small-cell lung cancer (SCLC) patients and identify patients who could benefit from prophylactic cranial irradiation (PCI) based on OS signature risk stratification.

MATERIALS AND METHODS

This study retrospectively included 556 SCLC patients from three medical centers. The training, internal validation, and external validation cohorts comprised 309, 133, and 114 patients, respectively. The OS signature was built using a unified fully connected neural network. A deep learning model was developed based on the OS signature. Clinical and combined models were developed and compared with a deep learning model. Additionally, the benefits of PCI were evaluated after stratification using an OS signature.

RESULTS

Within the internal and external validation cohorts, the deep learning model (concordance index [C-index] 0.745, 0.733) was far superior to the clinical model (C-index: 0.635, 0.630) in predicting OS, but slightly worse than the combined model (C-index: 0.771, 0.770). Additionally, the deep learning model had excellent calibration, clinical usefulness, and improved accuracy in classifying survival outcomes. Remarkably, patients at high risk had a survival benefit from PCI in both the limited and extensive stages (all P < 0.05), whereas no significant association was observed in patients at low risk.

CONCLUSIONS

The CT-based deep learning model exhibited promising performance in predicting the OS of SCLC patients. The OS signature may aid in individualized treatment planning to select patients who may benefit from PCI.

A practical nomogram for predicting early death in elderly small cell lung cancer patients: A SEER-based study

This study aimed to identify risk factors for early death in elderly small cell lung cancer (SCLC) patients and develop nomogram prediction models for all-cause and cancer-specific early death to improve patient management. Data of elderly patients diagnosed with SCLC were extracted from the SEER database, then randomly divided into training and validation cohorts. Univariate and stepwise multivariable Logistic regression analyses were performed on the training cohort to identify independent risk factors for early death in these patients. Nomograms were developed based on these factors to predict the overall risk of early death. The efficacy of the nomograms was validated using various methods, including ROC analysis, calibration curves, DCA, NRI, and IDI. Among 2077 elderly SCLC patients, 773 died within 3 months, 713 due to cancer-specific causes. Older age, higher AJCC staging, brain metastases, and lack of surgery, chemotherapy, or radiotherapy increase the risk of all-cause early death, while higher AJCC staging, brain metastases, lung metastases, and lack of surgery, chemotherapy, or radiotherapy increase the risk of cancer-specific death (P < .05). These identified factors were used to construct 2 nomograms to predict the risk of early death. The ROC indicated that the nomograms performed well in predicting both all-cause early death (AUC = 0.823 in the training cohort and AUC = 0.843 in the validation cohort) and cancer-specific early death (AUC = 0.814 in the training cohort and AUC = 0.841 in the validation cohort). The results of calibration curves, DCAs, NRI and IDI also showed that the 2 sets of nomograms had good predictive power and clinical utility and were superior to the commonly used TNM staging system. The nomogram prediction models constructed in this study can effectively assist clinicians in predicting the risk of early death in elderly SCLC patients, and can also help physicians screen patients at higher risk and develop personalized treatment plans for them.

Radiotherapy in the management of synchronous metastatic lung cancer

Metastatic lung cancer classically portends a poor prognosis. The management of metastatic lung cancer has dramatically changed with the emergence of immune checkpoint inhibitors, targeted therapy and due to a better understanding of the oligometastatic process. In metastatic lung cancers, radiation therapy which was only used with palliative intent for decades, represents today a promising way to treat primary and oligometastatic sites with a curative intent. Herein we present through a literature review the role of radiotherapy in the management of synchronous metastatic lung cancers.

Frequency of metastases within the hypothalamic-pituitary area and the associated high-risk factors in patients with brain metastases

Objective

Brain radiotherapy often results in impairment of hypothalamic-pituitary (HT-P) function, which in turn causes secretory dysfunction of related hormones. In this paper, the frequency of metastasis in the HT-P area and its high-risk factors in patients with brain metastasis were retrospectively analyzed, and thus provide experimental evidence for protecting HT-P area during whole brain radiotherapy (WBRT).

Methods

A retrospective analysis was performed on the data of patients with brain metastasis diagnosed by cranial magnetic resonance imaging (MRI) at the First Hospital of Lanzhou University from 2017 to 2020. The anatomical positions of the hypothalamus and pituitary were delineated, followed by their expansion by 5 mm outwards, respectively, in the three-dimensional direction, and the hypothalamus +5 mm and pituitary +5 mm were obtained as the avoidance area, in which the frequency of brain metastasis was evaluated. Univariate and multivariate logistic regression models were used to analyze the high risk factors of brain metastasis in HT-P area.

Results

A total of 3,375 brain metastatic lesions from 411 patients were included in the analysis. The rates of brain metastasis in the hypothalamus +5 mm and pituitary +5 mm in the whole group of cases were 2.9% (12/411) and 1.5% (6/411) respectively; the frequency of lesions was 0.4% (13/3375) and 0.2% (6/3375) respectively. Univariate and multivariate analyses showed that the number of brain metastases (OR = 14.946; 95% CI = 4.071-54.880; p < 0.001), and the occurrence of brain metastasis in the pituitary (OR = 13.331; 95% CI = 1.511-117.620; p = 0.020) were related to brain metastasis in the hypothalamus, and that the only relevant factor for brain metastasis in the pituitary was the occurrence of that in the hypothalamus (OR = 0.069; 95% CI = 0.010-0.461; p = 0.006). There was no correlation between tumor pathological types, the maximum diameter, the total volume of brain metastatic lesions and the risk of brain metastasis in hypothalamus and pituitary.

Conclusion

The frequency of brain metastasis in the HT-P area is extremely low. The risk of brain metastases in the hypothalamus is correlated with their number. The larger the number of metastatic lesions, the higher the frequency of brain metastasis. Protection of the HT-P area during WBRT may be unlikely to compromise the tumor recurrence rate for patients with a relatively small number of brain metastases.

Quality assurance and safety of hippocampal avoidance prophylactic cranial irradiation in the multicenter randomized phase III trial (NCT01780675)

Objective

NCT01780675, a multicenter randomized phase III trial of prophylactic cranial irradiation (PCI) versus PCI with hippocampal sparing in small cell lung cancer (SCLC) investigated neurocognitive decline and safety. As part of quality assurance, we evaluated if hippocampal avoidance (HA)-PCI was performed according to the NCT01780675 trial protocol instructions, and performed a safety analysis to study the incidence and location of brain metastases for patients treated with HA-PCI.

Methods

This retrospective analysis evaluated the quality of the irradiation given in the randomized controlled trial (RCT) comparing SCLC patients receiving PCI with or without hippocampal avoidance, using intensity modulated radiotherapy (IMRT) or volumetric modulated arc therapy (VMAT). The dose distribution for each patient receiving HA-PCI was retrieved and analyzed to evaluate if the treatment dose constraints were met. A questionnaire was sent out to all participating sites, and data on radiotherapy technique, pre-treatment dummy runs, phantom measurements and treatment electronic portal imaging device (EPID) dosimetry were collected and analyzed. As part of the safety analysis, the follow-up magnetic resonance imaging (MRI) or computerized tomography (CT) scans on which cranial disease progression was first diagnosed were collected and matched to the radiotherapy planning dose distribution. The matched scans were reviewed to analyze the location of the brain metastases in relation to the prescribed dose.

Results

A total of 168 patients were randomized in the NCT01780675 trial in 10 centers in the Netherlands and Belgium from April 2013 until March 2018. Eighty two patients receiving HA-PCI without evidence of brain metastases were analyzed. All patients were treated with 25 Gy in 10 fractions. Dummy runs and phantom measurements were performed in all institutions prior to enrolling patients into the study. The radiotherapy (RT) plans showed a median mean bilateral hippocampal dose of 8.0 Gy, range 5.4-11.4 (constraint ≤ 8.5 Gy). In six patients (7.3%) there was a protocol violation of the mean dose in one or both hippocampi. In four of these six patients (4.9%) the mean dose to both hippocampi exceeded the constraint, in 1 patient (1.2%) only the left and in 1 patient (1.2%) only the right hippocampal mean dose was violated (average median dose left and right 8.9 Gy). All patients met the trial dose constraint of V 115% PTV ≤ 1%; however the D max PTV constraint of ≤ 28.75 Gy was violated in 22.0% of the patients. The safety analysis showed that 14 patients (17.1%) developed cranial progression. No solitary brain metastases in the underdosed region were found. Two out of 11 patients with multiple brain metastasis developed metastasis in the underdosed region(s).

Conclusions

The radiotherapy quality within the HA-PCI trial is performed according to the protocol guidelines. The dose constraints to the hippocampi are met in the vast majority of cases. In all patients, the volume of the brain for which a higher dose was accepted, is according to the trial. However, within this volume there are small areas with higher doses than advised.

Risk factors for cognitive impairment in radically treated stage III NSCLC: Secondary findings of the NVALT-11 study

AIM

To identify risk factors for self-reported cognitive impairment in radically treated stage III non-small cell lung cancer (NSCLC).

METHODS

Cognitive functioning was assessed using the EORTC-QLQ-C30 at seven pre-specified time points in the phase III NVALT-11 trial (observation versus prophylactic cranial irradiation [PCI] in stage III NSCLC treated with chemo-radiotherapy±surgery). Cognition was analyzed as binary (impairment or not) and continuous outcome, respectively, using generalized estimating equation (GEE) before and after multiple imputation. A score <75 was defined as cognitive impairment. A mean difference by <10, 10-<20, ≥ 20 points was regarded as no, moderate, and large clinical effect, respectively. We categorized the cognitive impairment into four types based on changes over time: sustained, reversible, recurring, and alternating.

RESULTS

In the no-PCI arm, 43/84 [51.2%] reported cognitive impairment at least once, of which 31.4% were sustained, 25.7% reversible, 28.6% recurring, and 14.3% alternating. Results were similar in the PCI arm. Cognitive functioning at baseline was comparable in two arms and a score <75 was a significant risk factor with large effect for subsequent cognitive impairment (no-PCI: β = -22.30, p<0.001; PCI arm: β = -22.34, p<0.001; All: β = -23.47, p<0.001). Younger age (≤ 60y), squamous histology, and PCI were risk factors without clinical relevance (β > -10, p<0.05). Cognitive functioning declined over time (β = -0.26, p=0.001) except for patients with cognitive impairment at baseline (β=0.141, p=0.33).

CONCLUSION

Cognitive impairment is dynamic over time with four types. Baseline cognitive impairment (score <75) is the most important risk factor for subsequent cognitive impairment in stage III NSCLC. Note: This work has been partly reported as an oral presentation at the ESTRO 2021 meeting (OC-0176).

Use of radiation therapy among patients with Extensive-stage Small-cell lung cancer receiving Immunotherapy: Canadian consensus recommendations

OBJECTIVES

Thoracic radiation therapy (TRT) and prophylactic cranial irradiation (PCI) are commonly used in the management of extensive-stage small-cell lung cancer (ES-SCLC); however, Phase III trials of first-line immunotherapy often excluded these options. Guidance is needed regarding appropriate use of TRT, PCI, and magnetic resonance imaging (MRI) surveillance while new data are awaited.

MATERIALS AND METHODS

In two web-based meetings, a pan-Canadian expert working group of five radiation oncologists and four medical oncologists addressed eight clinical questions regarding use of radiation therapy (RT) and MRI surveillance among patients with ES-SCLC receiving immunotherapy. A targeted literature review was conducted using PubMed and conference proceedings to identify recent (January 2019-April 2022) publications in this setting. Fifteen recommendations were developed; online voting was conducted to gauge agreement with each recommendation.

RESULTS

After considering recently available evidence across lung cancer populations and clinical experience, the experts recommended that all patients with a response to chemo-immunotherapy, good performance status (PS), and limited metastases be considered for consolidation TRT (e.g., 30 Gy in 10 fractions). When considered appropriate after multidisciplinary team discussion, TRT can be initiated during maintenance immunotherapy. All patients who respond to concurrent chemo-immunotherapy should undergo restaging with brain MRI to guide decision-making regarding PCI versus MRI surveillance alone. MRI surveillance should be conducted for two years after response to initial therapy. PCI (e.g., 25 Gy in 10 fractions or 20 Gy in 5 fractions) can be considered for patients without central nervous system involvement who have a response to chemo-immunotherapy and good PS. Concurrent treatment with PCI and immunotherapy or with TRT, PCI, and immunotherapy is appropriate after completion of initial therapy. All recommendations were agreed upon unanimously.

CONCLUSIONS

These consensus recommendations provide practical guidance regarding appropriate use of RT and immunotherapy in ES-SCLC while awaiting new clinical trial data.

Brain metastases from small cell lung cancer and non-small cell lung cancer: comparison of spatial distribution and identification of metastatic risk regions

PURPOSE

This study aims to investigate the spatial distribution difference of brain metastases (BM) between small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC) and to identify the metastatic risk in brain regions.

METHODS

T1-enhanced MR images of 2997 BM from 728 eligible patients with SCLC and NSCLC were retrospectively reviewed by three independent medical institutions in China. All images were spatially normalised according to the Montreal Neurological Institute space, following BM delineation confirmed by three senior radiologists. The brain regions in the normalised images were identified based on the merged Anatomical Automatic Labeling atlas, and all BM locations were mapped onto these brain regions. Two-tailed proportional hypothesis testing was used to compare the BM observed rate with the expected rate based on the region's volume, and metastatic risk regions were finally identified.

RESULTS

In SCLC and NSCLC, BM was mainly present in the deep white matter (22.51% and 17.96%, respectively), cerebellar hemisphere (9.84% and 7.46%, respectively) and middle frontal gyrus (6.72% and 7.97%, respectively). The cerebellar hemisphere was a high-risk brain region in the SCLC. The precentral gyrus, middle frontal gyrus, paracentral lobule and cerebellar hemisphere were high-risk BM in the NSCLC. The inferior frontal gyrus and the temporal pole were a low-risk brain region in the SCLC and NSCLC, respectively.

CONCLUSION

The spatial BM distribution between SCLC and NSCLC is similar. Several critical brain regions had relatively low BM frequency in both SCLC and NSCLC, where a low-dose radiation distribution can be delivered due to adequate preoperative evaluations.

Synthesis of novel benzothiophene derivatives as protectors against cranial irradiation-induced neuroinflammation

Aim: Cranial irradiation results in many deleterious effects to normal tissues, including neuroinflammation. There is a need to explore radioprotective agents that could be safely used to ameliorate these effects. Method: Nine novel benzothiophene derivatives bearing pyrimidinone, pyrazolidinone, triazole and other active moieties were synthesized and evaluated as antioxidants in an in vitro screening experiment. The most potent compounds were then tested as protectors against radiation-induced neuroinflammation and oxidative stress in rat brains following cranial irradiation. Results: The most potent antioxidant compounds were compounds 3–5 and 10 . P-fluro,p- bromo and pyrido benzothiophene derivatives offered good antioxidant and anti-inflammatory effects. Conclusion: Compounds 3–5 may be introduced as nontoxic candidates for adjuvant therapeutic protocols used in head and neck tumor radiotherapeutic management.

Construction of Brain Metastasis Prediction Model and Optimization of Prophylactic Cranial Irradiation Selection for Limited-Stage Small-Cell Lung Cancer

Prophylactic cranial irradiation (PCI), as an essential part of the treatment of limited-stage small-cell lung cancer (LS-SCLC), inevitably leads to neurotoxicity. This study aimed to construct a brain metastasis prediction model and identify low-risk patients to avoid PCI; 236 patients with LS-SCLC were retrospectively analyzed and divided into PCI (63 cases) and non-PCI groups (173 cases). The nomogram was developed based on variables determined by univariate and multivariate analyses in the non-PCI group. According to the cutoff nomogram score, all patients were divided into high- and low-risk cohorts. A log-rank test was used to compare the incidence of brain metastasis between patients with and without PCI in the low-risk and high-risk groups, respectively. The nomogram included five variables: chemotherapy cycles (ChT cycles), time to radiotherapy (RT), lactate dehydrogenase (LDH), pro-gastrin-releasing peptide precursor (ProGRP), and lymphocytes−monocytes ratio (LMR). The area under the receiver operating characteristics (AUC) of the nomogram was 0.763 and 0.782 at 1 year, and 0.759 and 0.732 at 2 years in the training and validation cohorts, respectively. Based on the nomogram, patients were divided into high- and low-risk groups with a cutoff value of 165. In the high-risk cohort, the incidence of brain metastasis in the non-PCI group was significantly higher than in the PCI group (p < 0.001), but there was no difference in the low-risk cohort (p = 0.160). Propensity score-matching (PSM) analysis showed similar results; the proposed nomogram showed reliable performance in assessing the individualized brain metastasis risk and has the potential to become a clinical tool to individualize PCI treatment for LS-SCLC.

Risk Factors for Brain Metastases in Patients With Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

The use of prophylactic cranial irradiation (PCI) for small cell lung cancer (SCLC) patients is controversial. Risk factors for brain metastasis (BM) development are largely lacking, hampering personalized treatment strategies. This study aimed to identify the possible risk factors for BM in SCLC.We systematically searched the Pubmed database (1 January 1995 to 18 January 2021) according to the PRISMA guidelines. Eligibility criteria: studies reporting detailed BM data with an adequate sample size (randomized clinical trials [RCTs]: N ≥50; non-RCTs: N ≥100) in patients with SCLC. We summarized the reported risk factors and performed meta-analysis to estimate the pooled hazard ratios (HR) if enough qualified data (i.e., two or more studies; the same study type; the same analysis method; and HRs retrievable) were available. In total, 61/536 records were eligible (18 RCTs and 39 non-RCTs comprising 13,188 patients), in which 57 factors were reported. Ten factors qualified BM data for meta-analysis: Limited stage disease (LD) (HR = 0.34, 95% CI: 0.17–0.67; P = 0.002) and older age (≥65) (HR = 0.70, 95% CI: 0.54–0.92; P = 0.01) were associated with less BM; A higher T stage (≥T3) (HR = 1.72, 95% CI: 1.16–2.56; P = 0.007) was a significant risk factor for BM. Male sex (HR = 1.24, 95% CI: 0.99–1.54; P = 0.06) tended to be a risk factor, and better PS (0–1) (HR = 0.66, 95% CI: 0.42–1.02; P = 0.06) tended to have less BM. Smoking, thoracic radiotherapy dose were not significant (P >0.05). PCI significantly decreased BM (P <0.001), but did not improve OS in ED-SCLC (P = 0.81). A higher PCI dose did not improve OS (P = 0.11). The impact on BM was conflicting between Cox regression data (HR = 0.59, 95% CI: 0.26–1.31; P = 0.20) and competing risk regression data (HR = 0.74, 95% CI: 0.55–0.99; P = 0.04). Compared to M0–M1a, M1b was a risk factor for OS (P = 0.01) in ED-SCLC, but not for BM (P = 0.19). As regular brain imaging is rarely performed, high-quality data is lacking. Other factors such as N-stage and blood biomarkers had no qualified data to perform meta-analysis. In conclusion, younger age, higher T stage, and ED are risk factors for BM, suggesting that PCI should be especially discussed in such cases. Individual patient data (IPD) meta-analysis and well-designed RCTs are needed to better identify more risk factors and further confirm our findings. Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021228391, identifier CRD42021228391.

Hippocampal avoidance prophylactic cranial irradiation (HA-PCI) for small cell lung cancer reduces hippocampal atrophy compared to conventional PCI

BACKGROUND

Reducing radiation dose to the hippocampus with hippocampal avoidance prophylactic cranial irradiation (HA-PCI) is proposed to prevent cognitive decline. It has, however, not been investigated whether hippocampal atrophy is actually mitigated by this approach. Here, we determined whether HA-PCI reduces hippocampal atrophy. Additionally, we evaluated neurotoxicity of (HA-)PCI to other brain regions. Finally, we evaluated associations of hippocampal atrophy and brain neurotoxicity with memory decline.

METHODS

High-quality research MRI scans were acquired in the multicenter, randomized phase 3 trial NCT01780675. Hippocampal atrophy was evaluated for 4 months (57 HA-PCI patients and 46 PCI patients) and 12 months (28 HA-PCI patients and 27 PCI patients) after (HA-)PCI. We additionally studied multimodal indices of brain injury. Memory was assessed with the Hopkins Verbal Learning Test-Revised (HVLT-R).

RESULTS

HA-PCI reduced hippocampal atrophy at 4 months (1.8% for HA-PCI and 3.0% for PCI) and at 12 months (3.0% for HA-PCI and 5.8% for PCI). Both HA-PCI and PCI were associated with considerable reductions in gray matter and normal-appearing white matter, increases in white matter hyperintensities, and brain aging. There were no significant associations between hippocampal atrophy and memory.

CONCLUSIONS

HA-PCI reduces hippocampal atrophy at 4 and 12 months compared to regular PCI. Both types of radiotherapy are associated with considerable brain injury. We did not find evidence for excessive brain injury after HA-PCI relative to PCI. Hippocampal atrophy was not associated with memory decline in this population as measured with HVLT-R. The usefulness of HA-PCI is still subject to debate.

Memantine in the Prevention of Radiation-Induced Brain Damage: A Narrative Review

Simple Summary

Decline in cognitive function is a major problem for patients undergoing whole-brain radiotherapy (WBRT). Scientific interest has increased due to the high dropout rate of patients in the first months after WBRT and the early onset of cognitive decline. Therefore, the study of antiglutamatergic pharmacological prophylaxis and hippocampal-sparing WBRT techniques has been deepened based on the knowledge of the mechanisms of hyperglutamatergic neurotoxicity and the role of some hippocampal areas in cognitive decline. In order to provide a summary of the evidence in this field, and to foster future research in this setting, this literature review presents current evidence on the prevention of radiation-induced cognitive decline and particularly on the role of memantine.

Abstract

Preserving cognitive functions is a priority for most patients with brain metastases. Knowing the mechanisms of hyperglutamatergic neurotoxicity and the role of some hippocampal areas in cognitive decline (CD) led to testing both the antiglutamatergic pharmacological prophylaxis and hippocampal-sparing whole-brain radiotherapy (WBRT) techniques. These studies showed a relative reduction in CD four to six months after WBRT. However, the failure to achieve statistical significance in one study that tested memantine alone (RTOG 0614) led to widespread skepticism about this drug in the WBRT setting. Moreover, interest grew in the reasons for the strong patient dropout rates in the first few months after WBRT and for early CD onset. In fact, the latter can only partially be explained by subclinical tumor progression. An emerging interpretation of the (not only) cognitive impairment during and immediately after WBRT is the dysfunction of the limbic and hypothalamic system with its immune and hormonal consequences. This new understanding of WBRT-induced toxicity may represent the basis for further innovative trials. These studies should aim to: (i) evaluate in greater detail the cognitive effects and, more generally, the quality of life impairment during and immediately after WBRT; (ii) study the mechanisms producing these early effects; (iii) test in clinical studies, the modern and advanced WBRT techniques based on both hippocampal-sparing and hypothalamic-pituitary-sparing, currently evaluated only in planning studies; (iv) test new timings of antiglutamatergic drugs administration aimed at preventing not only late toxicity but also acute effects.

Efficacy of PD-1/PD-L1 Inhibitors versus Chemotherapy in Lung Cancer with Brain Metastases: A Systematic Review and Meta-Analysis

Immune checkpoint inhibitors (ICIs) are widely used to treat local or metastatic lung cancer. However, the efficacy of ICI in patients with brain metastases (BM) from lung cancer is unknown. This study aimed to evaluate the efficacy of PD-1/PD-L1 ICIs compared with chemotherapy for patients with lung cancer with BM. Electronic databases (PubMed, Embase, The Cochrane Library, and Web of Science) were searched. The meta-analysis assessed overall survival (OS) and progression-free survival (PFS) of the PD-1/PD-L1 inhibitors axis and its relationship with pathological type, drug modality, and the treatment line number in patients with BM from lung cancer. We included 694 patients with BM from lung cancer from 11 randomized controlled trials. Statistical analysis showed that compared with chemotherapy, PD-1/PD-L1 inhibitors could significantly prolong OS (hazard ratio (HR) = 0.75, 95%confidence interval (95%CI) = 0.51–0.99) and PFS (HR = 0.65, 95%CI = 0.51–0.80). In the subgroup analysis, ICIs plus chemotherapy improved PFS (HR = 0.60, 95%CI = 0.40–0.80), but not OS (HR = 0.75, 95%CI = 0.30–1.19). The efficacy of ICI monotherapy in patients with BM was significantly different between OS and PFS: OS pooled HR = 0.81 (95%CI = 0.57–1.05) and PFS = 0.78 (95%CI = 0.62–0.94). Among different pathological types, the OS pooled HR was 0.67 (95%CI = 0.39–0.95) for non-small cell lung cancer (NSCLC) and 0.94 (95%CI = 0.56–1.33) for small cell lung cancer (SCLC); the PFS pooled HR was 0.58 (95%CI = 0.39–0.76) for NSCLC and 0.79 (95%CI = 0.65–0.93) for SCLC. Subgroups analysis of treatment line showed that no advantage for OS with ICIs as first-line or subsequent-line therapy, whereas ICIs as first-line (HR = 0.63, 95%CI = 0.53–0.74) and second-line (HR = 0.62, 95%CI = 0.62–0.96) benefitted PFS. This meta-analysis implied that compared with chemotherapy, PD-1/PD-L1 inhibitors significantly improved efficacy treatment of patients with BM from lung cancer. Further studies are needed to confirm the role of ICIs in different pathological types and drug treatment modalities.

Pretreatment Thoracic CT Radiomic Features to Predict Brain Metastases in Patients With ALK-Rearranged Non-Small Cell Lung Cancer

Objective: To identify CT imaging biomarkers based on radiomic features for predicting brain metastases (BM) in patients with ALK-rearranged non-small cell lung cancer (NSCLC).

Methods: NSCLC patients with pathologically confirmed ALK rearrangement from January 2014 to December 2020 in our hospital were enrolled retrospectively in this study. Finally, 77 patients were included according to the inclusion and exclusion criteria. Patients were divided into two groups: BM+ were those patients who were diagnosed with BM at baseline examination (n = 16) or within 1 year’s follow-up (n = 14), and BM− were those without BM followed up for at least 1 year (n = 47). Radiomic features were extracted from the pretreatment thoracic CT images. Sequential univariate logistic regression, LASSO regression, and backward stepwise logistic regression were used to select radiomic features and develop a BM-predicting model.

Results: Five robust radiomic features were found to be independent predictors of BM. AUC for radiomics model was 0.828 (95% CI: 0.736–0.921), and when combined with clinical features, the AUC was increased (p = 0.017) to 0.909 (95% CI: 0.845–0.972). The individualized BM-predicting model incorporated with clinical features was visualized by the nomogram.

Conclusion: Radiomic features extracted from pretreatment thoracic CT images have the potential to predict BM within 1 year after detection of the primary tumor in patients with ALK-rearranged NSCLC. The radiomics model incorporated with clinical features shows improved risk stratification for such patients.

Role of Prophylactic Cranial Irradiation in Extensive-Stage Small Cell Lung Cancer

Patients with small cell lung cancer (SCLC) are at significant risk of developing brain metastases during their disease course. Prophylactic cranial irradiation (PCI) has been incorporated into SCLC treatment guidelines to diminish the risk of developing brain metastases. In 2007, a randomized trial suggested that PCI decreases the incidence of brain metastases and prolongs overall survival (OS) in patients with extensive-stage SCLC (ES-SCLC) who have responded to initial therapy. However, this study did not include modern central nervous system imaging with CT or MRI prior to randomization. A more recent Japanese trial with MRI staging and surveillance demonstrated that PCI diminished the incidence of brain metastases but did not improve survival. This review examines the largest clinical studies, controversies, and future directions of PCI in patients with ES-SCLC.

Prophylactic cranial irradiation (PCI), hippocampal avoidance (HA) whole brain radiotherapy (WBRT) and stereotactic radiosurgery (SRS) in small cell lung cancer (SCLC): Where do we stand?

Small cell lung cancer (SCLC) is an aggressive form of lung cancer associated with an increased risk of develping brain metastases (BM), which are a significant cause of morbidity and mortality. Prophylactic cranial irradiation (PCI) was first introduced in the 1970s with the aim of reducing BM incidence and improving survival and quality of life (QoL). Prospective clinical trials and meta-analyses have demonstrated its effectiveness in reducing BM incidence and improving survival, across all stages of the disease following response to induction chemotherapy. Despite its long history, "unknowns" surrounding PCI use still exist and there are particular subgroups of patients for which its use remains controversial. PCI is known to cause neurocognitive toxicity which can have a significant impact on a patient's QoL. Strategies to minimise this, including the use of hippocampal avoidance radiotherapy techniques, neuroprotective drugs and stereotactic radiosurgery in place of whole brain radiotherapy for the treatment of BM, are under evaluation. This review offers a summary of the key PCI trials published to date and the current treatment recommendations based on available evidence. It also discusses the key questions being addressed in ongoing clinical trials and highlights others where there is currently a knowledge gap and therefore where further data are urgently required.

TMEM100 negatively regulated by microRNA‑106b facilitates cellular apoptosis by suppressing survivin expression in NSCLC

Non‑small cell lung cancer (NSCLC) is a common malignant tumour. Nevertheless, the 5‑year survival rate of NSCLC patients remains poor. Thus, identifying critical factors involved in regulating the progression of NSCLC is important for providing potential treatment targets. In the present study, it was observed that transmembrane protein 100 (TMEM100) was significantly downregulated in NSCLC tissues compared with paired peritumoral tissues. Decreased TMEM100 expression was associated with poor clinical outcomes in NSCLC patients. Moreover, TMEM100 overexpression inhibited colony formation and facilitated apoptosis by suppressing survivin expression in NSCLC cells, whereas TMEM100 knockdown had the opposite effect. In addition, microRNA (miR)‑106b, a miR with controversial roles in different human cancers, was upregulated in NSCLC and directly downregulated TMEM100 expression. The roles of miR‑106b in cell survival were mitigated by the restoration of TMEM100. The aforementioned results indicated that TMEM100 induced cell apoptosis and inhibited cell survival by serving as a tumour suppressor and that miR‑106b‑mitigatedTMEM100 expression defined a potentially oncogenic pathway in NSCLC.

Exploration of spatial distribution of brain metastasis from small cell lung cancer and identification of metastatic risk level of brain regions: a multicenter, retrospective study

Objectives

This study aimed to explore the spatial distribution of brain metastases (BMs) from small cell lung cancer (SCLC) a homogenous sample, and to identify the metastatic risk levels in brain regions.

Methods

T1-enhanced magnetic resonance imaging (MRI) from SCLC patients were retrospectively reviewed from three medical institutions in China. All images were registered to the standard brain template provided by the Montreal Neurological Institute (MNI) 152 database, followed by transformation of the location of all BMs to the space of standard brain. The MNI structural atlas and Anatomical Automatic Labeling (AAL) atlas were then used to identify the anatomical brain regions, and the observed and expected rates of BMs were compared using 2-tailed proportional hypothesis testing. The locations and sizes of brain lesions were analyzed after image standardization.

Results

A total of 215 eligible patients with 1033 lesions were screened by MRI, including 157 (73%) males and 58 (27%) females. The incidence of crucial structures were as follows: hippocampus 0.68%, parahippocampal 0.97%, brainstem 2.05%, cauate 0.68%, putamen 0.68%, pallidum 0.2%, thalamus 1.36%. No BMs were found in the amygdala, pituitary gland, or pineal gland. The cumulative frequency of the important structures was 6.62%. Based on the results of MNI structural atlas, the cerebellum, deep white matter and brainstem was identified as a higher risk region than expected for BMs (P = 9.80 ×10⁻¹⁵, 9.04 ×10⁻⁶), whereas temporal lobe were low-risk regions (P = 1.65 ×10⁻⁴). More detailed AAL atlas revealed that the low-risk regions for BMs was inferior frontal gyrus (P = 6.971 ×10⁻⁴), while the high-risk regions for BMs was cerebellar hemispheres (P = 1.177 ×10⁻⁹).

Conclusion

Many crucial structures including the hippocampus, parahippocampus, pituitary gland and thalamus etc. have low frequency of brain metastases in a population of SCLC patients. This study provides the help to investigate the clinical feasibility of HA-WBRT and non-uniform dose of PCI in a population of SCLC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40644-021-00410-w.

Radiotherapy for brain metastases from small-cell lung cancer in distinct clinical indications and scenarios

Management of brain metastases (BM) from small-cell lung cancer (SCLC) is complex and not supported by a strong evidence from prospective clinical trials. Owing to the different clinical and pathological characteristics of SCLC, patients with this histology were not included in the prospective studies on the value of whole-brain radiotherapy (WBRT) and local surgical or ablative radiation treatment like stereotactic radiosurgery (SRS). Chemotherapy also represents a major part of the armamentarium against BM from SCLC due to the well-recognized chemoresponsiveness of this cancer and the frequent presentation of BM with extracranial progression. WBRT in combination with chemotherapy has long been a standard approach in this setting. However, data on the neurocognitive toxicity and the lack of documented impact on overall survival of WBRT in the management of BM from other solid tumors, as well as the increasing availability of the stereotactic radiotherapy technologies, has led to the increasing use of SRS with omission of WBRT also in SCLC. In the current review the use of different modalities of radiotherapy and ways of combining radiotherapy with chemotherapy for BM from SCLC will be presented for distinct clinical situations: presentation of BM synchronous with primary, metachronous presentation of BM—without previous prophylactic cranial irradiation (PCI) vs. after PCI, and asymptomatic BM found at the staging before PCI.

Prophylactic cranial irradiation in SCLC

Prophylactic cranial irradiation (PCI) has well established place in therapy for patients with limited-disease small cell lung cancer who responded to treatment. The data from randomized trials document that PCI reduces brain metastases rate from approximately 60% to 30%, and increases 3-year overall survival by approximately 5%. Currently, the dose of 25 Gy in 10 fractions is considered as standard. In attempt to reduce neuropsychological sequelae attributable to PCI hippocampal sparing techniques are employed. The existing studies suggest the benefit of hippocampal sparing in limiting memory and higher neurocognitive function losses, but with a risk of failures in the spared region. Ongoing studies will further validate the role of hippocampal sparing, both in terms of toxicity reduction and metastases prevention. PCI for patients who have undergone resection for stage I small cell lung cancer (SCLC) is not recommended, PCI may be, however, associated with a favourable outcome in SCLC patients who have undergone complete surgery in stages II−III. The role of PCI in extensive-disease (ED) SCLC has been evolving. Most recent evidence indicate that PCI is controversial in ED patients with response to initial chemotherapy and absence of brain metastases confirmed by contrast-enhanced MRI. The patients who do not receive PCI, must, however, receive periodic MRI examination during follow-up, i.e., remain under active surveillance with access to radiotherapy at brain relapse. The assessment of safety and effectiveness of hippocampal-sparing PCI, with or without drug neuroprotection in consideration of diverse combinations of radiotherapy, chemotherapy and immunotherapy create a background for future directions of research.

[The role of prophylactic cranial irradiation in small cell lung cancer]

INTRODUCTION

Prophylactic cranial irradiation (PCI) is considered standard therapeutic management in small cell lung cancer (SCLC). This is based on old randomised trials with methodological limitations, namely the absence of magnetic resonance imaging (MRI) of the brain. The aim of this study is to assess the risk not administering PCI when systematic brain imaging is applied.

METHODS

Retrospective study including untreated SCLC, without PCI and receiving brain imaging at the time of diagnosis. Kaplan-Meier and log-rank statistics were used for survival analyses.

RESULTS

Among 150 patients, 75 were possibly eligible for PCI. Thirteen patients presented with an isolated brain recurrence as the first site of progression with no other metastatic sites apparent, and in 6 patients, the brain was the only recurrent site during the whole follow-up. In the group of patients eligible for PCI, there was no statistically significant survival difference according to the brain progression status (P=0.11).

CONCLUSIONS

The expected impact of PCI seems limited in terms of overall survival and prevention of isolated brain metastases in patients having systematic brain imaging during SCLC work-up.

Phase 3 Randomized Trial of Prophylactic Cranial Irradiation With or Without Hippocampus Avoidance in SCLC (NCT01780675)

INTRODUCTION

To compare neurocognitive functioning in patients with SCLC who received prophylactic cranial irradiation (PCI) with or without hippocampus avoidance (HA).

METHODS

In a multicenter, randomized phase 3 trial (NCT01780675), patients with SCLC were randomized to standard PCI or HA-PCI of 25 Gy in 10 fractions. Neuropsychological tests were performed at baseline and 4, 8, 12, 18, and 24 months after PCI. The primary end point was total recall on the Hopkins Verbal Learning Test-Revised at 4 months; a decline of at least five points from baseline was considered a failure. Secondary end points included other cognitive outcomes, evaluation of the incidence, location of brain metastases, and overall survival.

RESULTS

From April 2013 to March 2018, a total of 168 patients were randomized. The median follow-up time was 26.6 months. In both treatment arms, 70% of the patients had limited disease and baseline characteristics were well balanced. Decline on the Hopkins Verbal Learning Test-Revised total recall score at 4 months was not significantly different between the arms: 29% of patients on PCI and 28% of patients on HA-PCI dropped greater than or equal to five points (p = 1.000). Performance on other cognitive tests measuring memory, executive function, attention, motor function, and processing speed did not change significantly different over time between the groups. The overall survival was not significantly different (p = 0.43). The cumulative incidence of brain metastases at 2 years was 20% (95% confidence interval: 12%-29%) for the PCI arm and 16% (95% confidence interval: 7%-24%) for the HA-PCI arm.

CONCLUSIONS

This randomized phase 3 trial did not find a lower probability of cognitive decline in patients with SCLC receiving HA-PCI compared with conventional PCI. No increase in brain metastases at 2 years was observed in the HA-PCI arm.

Treatment and toxic effects of prophylactic cranial irradiation in stage II-III non-small cell lung cancer: A meta-analysis

OBJECTIVE

To determine the role of prophylactic cranial irradiation (PCI) in non-small cell lung cancer (NSCLC) patients using meta-analysis.

METHODS

PubMed, Embase, the Cochrane Database of Systematic Review and the China National Knowledge Infrastructure databases were systematically searched for studies published between 1 January 1980 and 31 March 2019. Search terms included "non-small cell lung cancer," "prophylactic cranial irradiation" and "clinical trials." The research data extracted from above studies was analyzed by Review Manager 5.3 and Stata12.0 software. The outcomes included development of brain metastases (BMs), overall survival (OS), disease-free survival (DFS), BMs for different diagnoses, toxicity, quality of life (QoL).

RESULTS

Fifteen trials (nine RCTs and six non-RCTs) involving 2418 NSCLC patients met the inclusion criteria. There was a significant reduction in the risk of developing BM in patients who received PCI compared with those who did not (95% CI, 0.20-0.37; P < 0.00001). PCI significantly reduced the BM of squamous cell carcinoma (P = 0.02), but not for adenocarcinoma (P = 0.07) and other pathological types (P = 0.29). There was a significant increase in DFS for the PCI compared to the non-PCI group (P = 0.006); however, OS did not significantly differ (P = 0.15). In addition, fatigue significantly increased in the PCI group (P = 0.0002). Cognitive disturbance showed no significant difference between PCI and non-PCI groups (P = 0.06).

CONCLUSION

This study showed that, compared with non-PCI, PCI significantly decreased the incidence of NSCLC BM and improved the DFS of patients, and reduced the BM rate from squamous cell carcinoma. However, it showed no effect on OS and the BM rate of adenocarcinoma and other pathological types of tumors. There were limited data concerning PCI-related toxicity and QoL.

Current Management and Progress in Radiotherapy for Small Cell Lung Cancer

Radiotherapy (RT) and chemotherapy continue to be widely utilized in small cell lung cancer (SCLC) management. In most limited stage (LS)-SCLC cases, the standard initial therapy remains concurrent chemoradiotherapy (CRT), typically with an etoposide and platinum-based regimen. Hyperfractionated twice daily (BID) RT remains the standard of care, though conventional daily (QD) RT is now a viable alternative supported by randomized evidence. In LS-SCLC patients who experienced good response to CRT, prophylactic cranial irradiation (PCI) remains the standard of care. Brain imaging, ideally with MRI, should be performed prior to PCI to screen for clinically apparent brain metastases that may require a higher dose of cranial irradiation. Platinum doublet chemotherapy alone is the historic standard initial therapy in extensive stage (ES)-SCLC. Addition of immunotherapy such as atezolizumab and durvalumab to chemotherapy is now recommended after their benefits were demonstrated in recent trials. In patients with response to chemotherapy, consolidation thoracic RT and PCI could be considered, though with caveats. Emergence of hippocampal avoidance cranial irradiation and SRS in SCLC patients may supplant whole cranial irradiation as future standards of care. Incorporation of novel systemic therapies such as immunotherapies has changed the treatment paradigm and overall outlook of patients with SCLC. This narrative review summarizes the current state, ongoing trials, and future directions of radiotherapy in management of SCLC.

Risk factors for neurocognitive decline in lung cancer patients treated with prophylactic cranial irradiation: A systematic review

BACKGROUND

Prophylactic cranial irradiation (PCI) reduces brain metastasis incidence in lung cancer, however with risk of neurocognitive decline. Nevertheless, risk factors for neurocognitive decline after PCI remain unclear.

METHODS

We systematically reviewed the PubMed database according to the PRISMA guideline. Inclusion criteria were: randomized clinical trials (RCTs) and observational/single arm trials evaluating PCI, including ≥20 patients, reporting neurocognitive test results for lung cancer. Primary aim: evaluate risk factors associated with neurocognitive decline after PCI.

RESULTS

Twenty records were eligible (8 different RCTs, 8 observational studies), including 3553 patients in total (858 NSCLC, 2695 SCLC) of which 73.6% received PCI. Incidence of mild/moderate cognitive decline after PCI varied from 8 to 89% (grading not always provided); for those without PCI, this was 3.4-42%. Interestingly, 23-95% had baseline cognitive impairment. Risk factors were often not reported. In one trial, both age (>60 years) and higher PCI dose (36 Gy) including twice-daily PCI were associated with a higher risk of cognitive decline. In one trial, white matter abnormalities were more frequent in the concurrent or sandwiched PCI arm, but without significant neuropsychological differences. One trial identified hippocampal sparing PCI to limit the neurocognitive toxicities of PCI and another reported an association between hippocampal dose volume effects and memory decline. As neurocognition was a secondary endpoint in most RCTs, and was assessed by various instruments with often poor/moderate compliance, high-quality data is lacking.

CONCLUSIONS

Age, PCI dose, regimen and timing might be associated with cognitive impairment after PCI in lung cancer patients, but high-quality data is lacking. Future PCI trials should collect and evaluate possible risk factors systematically.

Improving tumor hypoxia and radiotherapy resistance via in situ nitric oxide release strategy

Radiation therapy remains one of the main treatments for cancer. However, conventional radiotherapy not only manifests a low radiation accumulation in the tumor site, but also displays numerous negative effects. The most serious clinical problem is the radiotherapy resistance leading to cancer deterioration. As an important gaseous signal molecule, nitric oxide (NO) has been widely studied for its role in regulating angiogenesis, improving hypoxia, and inhibiting tumor growth. However, due to the unstable characteristic, the application of NO in cancer therapy is still limited. Here, we designed a micellar system formed by a NO donor, D-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS)-NO, for enabling sustained NO release to efficiently deliver NO into the tumor area. TPGS-NO could accumulate in the tumor site for extended circulation, thereby releasing NO to exert antitumor effects and enhance radiotherapy effects under low-oxygen conditions. It demonstrated the increased sensitivity of radiotherapy through enhancing tumor angiogenesis appropriately reducing tumor area hypoxia, which significantly induced tumor cell apoptosis and inhibited its repair during radiation. This work may show great potential in synergistic radiotherapy against cancer by facile NO donor administration.

Does surgically resected small-cell lung cancer without lymph node involvement benefit from prophylactic cranial irradiation?

BACKGROUND

It has previously been demonstrated that surgically resected small-cell lung cancer (SCLC) patients could benefit from prophylactic cranial irradiation (PCI). However, PCI in patients without lymph node involvement remains controversial. This study includes a larger sample size to evaluate the benefit of PCI therapy in this specific population.

METHODS

The records of surgically resected SCLC patients without lymph node involvement (N0M0) in Shanghai Chest Hospital were retrospectively reviewed.

RESULTS

Between January 2006 and May 2017, a total of 146 cases of surgically resected SCLC without lymph node involvement were included. A total of 46 patients received PCI therapy and 100 patients received no therapy. During the observation period, 12.0% (12/100) of the patients who did not receive PCI therapy developed brain metastases while 10.9% (5/46) of patients who received PCI therapy developed brain metastases. With regard to time to recurrence, no significant difference was observed among the groups (P = 0.798). Moreover, there was no significant difference in either the overall survival benefit (hazard ratio [HR] = 0.84, 95% confidence interval [CI]: 0.49-1.45, P = 0.532) or disease-free survival rate (HR = 0.95, 95% CI: 0.52-1.75, P = 0.864).

CONCLUSIONS

The evidence obtained does not support PCI therapy in the management of surgically resected SCLC with no lymph node involvement.

KEY POINTS

Prophylactic cranial irradiation (PCI) remains controversial for resected small-cell lung cancer (SCLC) without lymph node involvement. In this study, the results indicated that PCI does not reduce the risk of cerebral recurrence of resected p-T1-2N0M0 SCLC. This is the largest sample size study focused on PCI in resected p-T1-2N0M0 SCLC. Future revised versions of the guidelines should address this issue.

Prophylactic Cranial Irradiation vs Observation in Patients With Locally Advanced Non-Small Cell Lung Cancer: A Long-term Update of the NRG Oncology/RTOG 0214 Phase 3 Randomized Clinical Trial

Importance

Brain metastasis (BM) rates are high in locally advanced non-small cell lung cancer (LA-NSCLC), approaching rates seen in small cell lung cancer, where prophylactic cranial irradiation (PCI) is standard of care. Although PCI decreases the incidence of BM in LA-NSCLC, a survival advantage has not yet been shown.

Objective

To determine if PCI improves survival in LA-NSCLC.

Design, Setting, and Participants

Radiation Therapy Oncology Group (RTOG) 0214 was a randomized phase 3 clinical trial in stage III NSCLC stratified by stage (IIIA vs IIIB), histologic characteristics (nonsquamous vs squamous) and therapy (no surgery vs surgery). The study took place at 291 institutions in the United States, Canada, and internationally. Of 356 patients with stage III NSCLC entered onto this study, 16 were ineligible; therefore, 340 patients were randomized.

Intervention for Clinical Trials

Observation vs PCI.

Main Outcomes and Measures

The primary outcome was overall survival (OS). The secondary end points were disease-free survival (DFS) and incidence of BM.

Results

Of the 340 total participants, mean (SD) age was 61 years; 213 of the participants were men and 127 were women. The median follow-up time was 2.1 years for all patients, and 9.2 years for living patients. The OS for PCI was not significantly better than observation (hazard ratio [HR], 0.82; 95% CI, 0.63-1.06; P = .12; 5- and 10-year rates, 24.7% and 17.6% vs 26.0% and 13.3%, respectively), while the DFS (HR, 0.76; 95% CI, 0.59-0.97; P = .03; 5- and 10-year rates, 19.0% and 12.6% vs 16.1% and 7.5% for PCI vs observation) and BM (HR, 0.43; 95% CI, 0.24-0.77; P = .003; 5- and 10-year rates, 16.7% vs 28.3% for PCI vs observation) were significantly different. Patients in the PCI arm were 57% less likely to develop BM than those in the observation arm. Younger patients (<60 years) and patients with nonsquamous disease developed more BM. On multivariable analysis, PCI was associated with decreased BM and improved DFS, but not improved OS. Multivariable analysis within the nonsurgical arm suggests that PCI effectively prolongs OS, DFS, and BM.

Conclusions and Relevance

In patients with stage III LA-NSCLC without progression of disease after therapy, PCI decreased the 5- and 10-year rate of BM and improved 5- and 10-year DFS, but did not improve OS. Although this study did not meet its primary end point, the long-term results reveal many important findings that will benefit future trials. Identifying the appropriate patient population and a safe intervention is critical.

Trial Registration

ClinicalTrials.gov identifier: NCT00048997.

The Role of Prophylactic Cranial Irradiation in Patients With Non-small Cell Lung Cancer: An Updated Systematic Review and Meta-Analysis

Background: The purpose of this study was to reevaluate the efficacy of prophylactic cranial irradiation (PCI) in non-small cell lung cancer (NSCLC) with the most recent published data and to identify subgroups who may be more likely to gain benefit from PCI.

Methods: We searched PubMed, Embase, and Cochrane databases for randomized trials comparing PCI with non-PCI in NSCLC patients. We pooled the data of randomized controlled trials and compared brain metastasis (BM) and overall survival (OS) between PCI group and non-PCI group.

Results: Seven studies including 1,462 patients were eligible for the current meta-analysis. Compared to non-PCI group, PCI group achieved decreased BM (RR = 0.37, 95% CI: 0.26–0.52) but similar OS (HR = 1.01, 95% CI: 0.87–1.22). In subgroup analyses of BM, PCI decreased BM for subgroups by pathology (squamous cell carcinoma or non-squamous cell carcinoma) and local treatment modality (surgery or no surgery). However, PCI failed to reduce BM for patients with poor performance status (WHO 2–3). The incidence of PCI related toxicities was low and PCI was well-tolerated by the majority of NSCLC. Low grade neurocognitive function (NCF) decline was reported in NAVLT study and greater deterioration in immediate and delayed recall was reported in RTOG 0214. No significant difference in quality of life (QOL) after PCI was reported.

Conclusion: PCI reduces the incidence of BM except for patients with poor performance status. However, PCI fails to prolong OS significantly for NSCLC. An individual patient data meta-analysis may identify patients that could achieve OS prolongation with PCI.

Patterns of brain metastasis immediately before prophylactic cranial irradiation (PCI): implications for PCI optimization in limited-stage small cell lung cancer

Background

Prophylactic cranial irradiation (PCI) is indicated for limited-stage small cell lung cancer (LS-SCLC) with good response to chemoradiotherapy (CRT). However, brain metastasis (BM) developed in LS-SCLC before PCI is not rare. In this study, we comprehensively investigated the features of pre-PCI BMs, aiming to explore the potential of PCI optimization for LS-SCLC.

Methods

One-hundred-ten LS-SCLC patients achieving clinical complete remission after definitive CRT with contrast-enhanced cranial magnetic resonance imaging (MRI) at baseline and immediately before PCI were included. The time trend and risk factors for pre-PCI BM were evaluated. Several radiological features, including numbers, sizes, and locations of pre-PCI BMs, were investigated to explore the technical feasibility of stereotactic radiotherapy and hippocampal-avoidance (HA) PCI.

Results

Twenty-four (21.8%) of the LS-SCLC patients harbored pre-PCI BM, all except one were asymptomatic. CRT duration (CRT-D) was the only independent risk factor for pre-PCI BM. The pre-PCI BM rate gradually increased in line with a growing time interval between treatment initiation and pre-PCI MRI. Pre-PCI BM and prolonged CRT-D were both correlated with worse overall survival. Of 129 pre-PCI intracranial lesions, 2 (1.5%) were in the HA region. Eight of the 24 (33.3%) pre-PCI BM patients were ineligible for stereotactic radiotherapy.

Conclusion

Our findings suggest that PCI is still of importance in LS-SCLC, and MRI evaluation before PCI is indispensable. Investigations are warranted to explore the possibility of moving PCI up to before CRT completion in LS-SCLC patients with prolonged CRT-D. HA-PCI could be considered to reduce neurotoxicity.

Electronic supplementary material

The online version of this article (10.1186/s13014-019-1371-4) contains supplementary material, which is available to authorized users.

Non-linear registration improves statistical power to detect hippocampal atrophy in aging and dementia

OBJECTIVE

To compare the performance of different methods for determining hippocampal atrophy rates using longitudinal MRI scans in aging and Alzheimer's disease (AD).

BACKGROUND

Quantifying hippocampal atrophy caused by neurodegenerative diseases is important to follow the course of the disease. In dementia, the efficacy of new therapies can be partially assessed by measuring their effect on hippocampal atrophy. In radiotherapy, the quantification of radiation-induced hippocampal volume loss is of interest to quantify radiation damage. We evaluated plausibility, reproducibility and sensitivity of eight commonly used methods to determine hippocampal atrophy rates using test-retest scans.

MATERIALS AND METHODS

Manual, FSL-FIRST, FreeSurfer, multi-atlas segmentation (MALF) and non-linear registration methods (Elastix, NiftyReg, ANTs and MIRTK) were used to determine hippocampal atrophy rates on longitudinal T1-weighted MRI from the ADNI database. Appropriate parameters for the non-linear registration methods were determined using a small training dataset (N = 16) in which two-year hippocampal atrophy was measured using test-retest scans of 8 subjects with low and 8 subjects with high atrophy rates. On a larger dataset of 20 controls, 40 mild cognitive impairment (MCI) and 20  AD patients, one-year hippocampal atrophy rates were measured. A repeated measures ANOVA analysis was performed to determine differences between controls, MCI and AD patients. For each method we calculated effect sizes and the required sample sizes to detect one-year volume change between controls and MCI (NCTRL_MCI) and between controls and AD (NCTRL_AD). Finally, reproducibility of hippocampal atrophy rates was assessed using within-session rescans and expressed as an average distance measure DAve, which expresses the difference in atrophy rate, averaged over all subjects. The same DAve was used to determine the agreement between different methods.

RESULTS

Except for MALF, all methods detected a significant group difference between CTRL and AD, but none could find a significant difference between the CTRL and MCI. FreeSurfer and MIRTK required the lowest sample sizes (FreeSurfer: NCTRL_MCI = 115, NCTRL_AD = 17 with DAve = 3.26%; MIRTK: NCTRL_MCI = 97, NCTRL_AD = 11 with DAve = 3.76%), while ANTs was most reproducible (NCTRL_MCI = 162, NCTRL_AD = 37 with DAve = 1.06%), followed by Elastix (NCTRL_MCI = 226, NCTRL_AD = 15 with DAve = 1.78%) and NiftyReg (NCTRL_MCI = 193, NCTRL_AD = 14 with DAve = 2.11%). Manually measured hippocampal atrophy rates required largest sample sizes to detect volume change and were poorly reproduced (NCTRL_MCI = 452, NCTRL_AD = 87 with DAve = 12.39%). Atrophy rates of non-linear registration methods also agreed best with each other.

DISCUSSION AND CONCLUSION

Non-linear registration methods were most consistent in determining hippocampal atrophy and because of their better reproducibility, methods, such as ANTs, Elastix and NiftyReg, are preferred for determining hippocampal atrophy rates on longitudinal MRI. Since performances of non-linear registration methods are well comparable, the preferred method would mostly depend on computational efficiency.

A new proposal of utilizing intraoperative electron radiation therapy on the surface of liver to prevent postoperative liver metastasis of pancreatic cancer

Pancreatic cancer is a lethal cancer with high rate of liver metastasis worldwide, whereas its treatment choices are limited to a large extent. The limitation of current therapeutic strategies calls for an effective approach which can lower the postoperative liver metastasis rate in order to improve the overall prognosis and survival rate. Comprehensively considering the basic knowledge and clinical practice of tumor treatment worldwide, we proposed three points of hypotheses. Basically, the existing evidences indicated that tumor cells shedding from pancreatic cancer localized in the marginal liver preferentially through the Portal vein. Then, the percentage depth dose distribution of electron radiation is consistent with the marginal distribution of liver metastasis from pancreatic cancer. Based on the characteristics of liver metastasis of pancreatic cancer and the percentage depth dose of electron radiation, we provide a new propose of preventing postoperative liver metastasis in a way of prophylactic intraoperative electron radiation therapy on the surface of liver. Intraoperative electron radiation is relatively easy to control radiation dose and treatment area under direct vision, effectively inhibiting the metastasis and growth of cancer cells and preventing further deterioration of pancreatic cancer patients' condition. Therefore, this hypothesis has an important clinical significance for postoperative rehabilitation and improvement of patients' survival.

Radiotherapy toxicity

Radiotherapy is used in >50% of patients with cancer, both for curative and palliative purposes. Radiotherapy uses ionizing radiation to target and kill tumour tissue, but normal tissue can also be damaged, leading to toxicity. Modern and precise radiotherapy techniques, such as intensity-modulated radiotherapy, may prevent toxicity, but some patients still experience adverse effects. The physiopathology of toxicity is dependent on many parameters, such as the location of irradiation or the functional status of organs at risk. Knowledge of the mechanisms leads to a more rational approach for controlling radiotherapy toxicity, which may result in improved symptom control and quality of life for patients. This improved quality of life is particularly important in paediatric patients, who may live for many years with the long-term effects of radiotherapy. Notably, signs and symptoms occurring after radiotherapy may not be due to the treatment but to an exacerbation of existing conditions or to the development of new diseases. Although differential diagnosis may be difficult, it has important consequences for patients.

Application of prophylactic cranial irradiation in limited-stage small-cell lung cancer: which patients could benefit?

Aim: To analyze the role of prophylactic cranial irradiation (PCI) on the survival for patients with limited-stage small-cell lung cancer (LS-SCLC). Patients & methods: We screened patients from SEER database. Kaplan–Meier analysis and Cox proportional hazard model were used to evaluate factors influencing survival. Results: LS-SCLC patients who receiving PCI were associated with better overall survival (OS; p < 0.001) and cancer-specific survival (CSS; p < 0.001). Multivariable Cox analysis revealed PCI was an independent prognostic factor for OS (p < 0.001) and CSS (p < 0.001). In subgroup analysis, there were no OS and CSS differences between PCI and no PCI groups in black patients and patient with a tumor size <5 cm (all p > 0.05). Conclusion: PCI remains an effective method for most LS-SCLC patients. However, caution should be taken in recommending PCI for black patients and patients with a tumor size <5 cm. Further clinical trials are necessary to validate our results and identify the most suitable patients for PCI in the modern era.

Case of metastatic small cell carcinoma of the oropharynx successfully treated with image-guided volumetric modulated arc therapy (IG-VMAT): pushing the limits of technology to match treatment intent

Extrapulmonary small cell carcinomas (EPSCC) are a rare subtype of neuroendocrine tumours which have been documented to arise from a multitude of sites and treatment outcomes are disappointing. The most common site involved in the head and neck region is the larynx and the oropharynx as a primary site has been infrequently reported. The patient presented with bilateral neck swelling and an ulcerated lesion was noted in the base of tongue (BOT). A biopsy revealed small cell carcinoma (SCC) and was confirmed with immunohistochemistry. The final diagnosis after workup was SCC of BOT stage IVc. He received induction chemotherapy to which the tumour responded partially, followed by curative intent chemoradiotherapy and adjuvant chemotherapy. The patient achieved a radiological complete response to treatment and almost all treatment-induced toxicities resolved. An aggressive approach to managing EPSCC is possible with modern radiotherapy techniques, with tolerable treatment-induced toxicities.

GAP43, a novel metastasis promoter in non-small cell lung cancer

BACKGROUND

Brain metastasis is an extremely serious sequela with a dismal prognosis in non-small cell lung cancer (NSCLC). The present study aimed to identify novel biomarkers and potential therapeutic targets for brain metastases of NSCLC.

METHODS

We performed high-throughput Luminex assays to profile the transcriptional levels of 36 genes in 70 operable NSCLC patients, among whom 37 developed brain metastases as the first relapse within 3 years after surgery. The Cox proportional hazards regression model was used to evaluate the association between genes and brain metastases. Wound healing assay and transwell assay was carried out to estimate the function of target gene in vitro. And left ventricular injection on nude mice was used to evaluate the effect of target gene in vivo.

RESULTS

Growth-associated protein 43 (GAP43) was found to be related to brain metastasis. Multivariate Cox regression analysis showed that NSCLC patients with elevated GAP43 had a 3.29-fold increase in the risk for brain metastasis compared with those with low levels (95% confidence interval: 1.55-7.00; P = 0.002). Kaplan-Meier survival curves revealed that GAP43 was also associated with overall survival. Analysis of a cohort of 1926 NSCLC patients showed similar results: patients with high levels of GAP43 had worse progression-free and overall survival rates. Furthermore, in vitro experiments showed that GAP43 facilitated cell migration. Animal studies demonstrated that GAP43-silenced NSCLC cells were less likely to metastasize to the brain and bone than control cells. Immunofluorescence and F-actin/G-actin in vivo assays indicated that GAP43 knockdown triggered depolymerization of the F-actin cytoskeleton. Rho GTPase activation assays showed that Rac1 was deactivated after GAP43 was silenced.

CONCLUSIONS

Our findings suggest that GAP43 is an independent predictor of NSCLC brain metastasis and that it may facilitate metastasis by regulating the Rac1/F-actin pathway.

Inter-observer variation of hippocampus delineation in hippocampal avoidance prophylactic cranial irradiation

BACKGROUND

Hippocampal avoidance prophylactic cranial irradiation (HA-PCI) techniques have been developed to reduce radiation damage to the hippocampus. An inter-observer hippocampus delineation analysis was performed and the influence of the delineation variability on dose to the hippocampus was studied.

MATERIALS AND METHODS

For five patients, seven observers delineated both hippocampi on brain MRI. The intra-class correlation (ICC) with absolute agreement and the generalized conformity index (CI_gen) were computed. Median surfaces over all observers' delineations were created for each patient and regional outlining differences were analysed. HA-PCI dose plans were made from the median surfaces and we investigated whether dose constraints in the hippocampus could be met for all delineations.

RESULTS

The ICC for the left and right hippocampus was 0.56 and 0.69, respectively, while the CI_gen ranged from 0.55 to 0.70. The posterior and anterior-medial hippocampal regions had most variation with SDs ranging from approximately 1 to 2.5 mm. The mean dose (D_mean) constraint was met for all delineations, but for the dose received by 1% of the hippocampal volume (D_1%) violations were observed.

CONCLUSION

The relatively low ICC and CI_gen indicate that delineation variability among observers for both left and right hippocampus was large. The posterior and anterior-medial border have the largest delineation inaccuracy. The hippocampus D_mean constraint was not violated.

Prophylactic Cranial Irradiation Versus Observation in Radically Treated Stage III Non-Small-Cell Lung Cancer: A Randomized Phase III NVALT-11/DLCRG-02 Study

Purpose The purpose of the current study was to investigate whether prophylactic cranial irradiation (PCI) reduces the incidence of symptomatic brain metastases in patients with stage III non-small-cell lung cancer (NSCLC) treated with curative intention. Patients and Methods Patients with stage III NSCLC-staged with a contrast-enhanced brain computed tomography or magnetic resonance imaging-were randomly assigned to either observation or PCI after concurrent/sequential chemoradiotherapy with or without surgery. The primary end point-development of symptomatic brain metastases at 24 months-was defined as one or a combination of key symptoms that suggest brain metastases-signs of increased intracranial pressure, headache, nausea and vomiting, cognitive or affective disturbances, seizures, and focal neurologic symptoms-and magnetic resonance imaging or computed tomography demonstrating the existence of brain metastasis. Adverse effects, survival, quality of life, quality-adjusted survival, and health care costs were secondary end points. Results Between 2009 and 2015, 175 patients were randomly assigned: 87 received PCI and 88 underwent observation only. Median follow-up was 48.5 months (95% CI, 39 to 54 months). Six (7.0%) of 86 patients in the PCI group and 24 (27.2%) of 88 patients in the control group had symptomatic brain metastases ( P = .001). PCI significantly increased the time to develop symptomatic brain metastases (hazard ratio, 0.23; [95% CI, 0.09 to 0.56]; P = .0012). Median time to develop brain metastases was not reached in either arm. Overall survival was not significantly different between both arms. Grade 1 and 2 memory impairment (26 of 86 v seven of 88 patients) and cognitive disturbance (16 of 86 v three of 88 patients) were significantly increased in the PCI arm. Quality of life was only decreased 3 months post-PCI and was similar to the observation arm thereafter. Conclusion PCI significantly decreased the proportion of patients who developed symptomatic brain metastases with an increase of low-grade toxicity.

Effect of Prophylactic Cranial Irradiation on Overall Survival in Metastatic Small-Cell Lung Cancer: A Propensity Score-Matched Analysis

INTRODUCTION

Patients with small-cell lung cancer (SCLC) have a high incidence of occult brain metastases and are often treated with prophylactic cranial irradiation (PCI). Despite a small survival advantage in some studies, the role of PCI in extensive stage SCLC remains controversial. We used the National Cancer Database to assess survival of patients with metastatic SCLC treated with PCI.

PATIENTS AND METHODS

Metastatic SCLC patients without brain metastases were identified. To minimize treatment selection bias, patients with an overall survival (OS) < 6 months were excluded. Cox regression identified variables associated with OS. Patients were propensity score-matched on factors associated with receipt of PCI or OS. The effect of PCI on OS was examined using Kaplan-Meier estimates.

RESULTS

In the overall cohort (n = 4257), treatment with PCI (n = 473) was associated with improved survival (hazard ratio, 0.66; 95% confidence interval, 0.60-0.74; P < .0001). Comparisons of propensity score-matched cohorts revealed a significant survival benefit for patients who received PCI in median OS (13.9 vs. 11.1 months; P < .0001), as well as 1- and 2-year OS (61.2% vs. 44.0% and 19.8% vs. 11.5%, respectively; P < .0001). This survival benefit persisted even after excluding patients who survived < 9 months (median: 15.3 vs. 12.9 months; P < .0001). In multivariable analysis, predictors of receipt of PCI were Caucasian race, younger age, and lower Charlson-Deyo score.

CONCLUSION

Using a modern population-based data set, we showed that metastatic SCLC patients treated with PCI have significantly improved OS. This large retrospective study helps address the conflicting prospective data.

Prophylactic Cranial Irradiation in Patients With Non-Small-Cell Lung Cancer: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

We systematically reviewed the literature for trials addressing the efficacy of prophylactic cranial irradiation (PCI) in patients with non-small-cell lung cancer (NSCLC) treated with a curative intent.

METHODS

Randomized controlled trials (RCT) comparing PCI to no PCI in patients with NSCLC treated with a curative intent were eligible for inclusion. We searched EMBASE, MEDLINE, PubMed, and CENTRAL between 1946 and July 2016. We also received continual search alerts from PubMed through September 2017. Search terms included "non-small-cell lung carcinoma," "cranial irradiation," and "randomized controlled trials." We conducted meta-analyses using random-effects models for relative measures of treatment effect for the incidence of brain metastasis, overall survival (OS), and disease-free survival (DFS). We used Parmar's methodology to derive hazard ratios (HR) when not explicitly stated in RCTs. We narratively synthesized data for the impact of PCI on quality of life (QoL) and neurocognitive function (NCF). We assessed the quality of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation methodology.

RESULTS

Out of 3,548 citations captured by the search strategy, we retained 8 papers and 1 abstract, reporting on 6 eligible trials. Patients who received PCI had a significant reduction in the risk of developing brain metastases as compared with patients who did not [relative risk (RR) = 0.37; 95% confidence interval (CI): 0.26-0.52; moderate quality evidence]. However, there was no OS benefit (HR = 1.08, 95% CI: 0.90-1.31; moderate quality evidence). Sensitivity analysis excluding older studies did not show substantively different findings. DFS was reported in the two most recent trials that included only stage III patients. There was significant improvement in DFS with PCI (HR = 0.67; 95% CI: 0.46-0.98; high quality evidence). Two studies that reported on QoL reported no statistically significant differences. There was no significant difference in NCF decline in the only study that reported on this outcome, except in immediate and delayed recall, as assessed by the Hopkins Verbal Learning Test.

CONCLUSION

There is moderate quality evidence that the use of PCI in patients with NSCLC decreases the risk of brain metastases, but does not provide an OS benefit. However, data limited to stage III patients suggests that PCI improves DFS, with no effect on QoL.