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?

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.

The association between graded prognostic assessment and the prognosis of brain metastases after whole brain radiotherapy: a meta-analysis

Introduction

This meta-analysis aims to provide evidence-based medical evidence for formulating rational treatment strategies and evaluating the prognosis of brain metastasis (BM) patients by assessing the effectiveness of the graded prognostic assessment (GPA) model in predicting the survival prognosis of patients with BM after whole-brain radiotherapy (WBRT).

Methods

A comprehensive search was conducted in multiple databases, including the China Biomedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), PubMed, Wanfang database, Cochrane Library, Web of Science, and Embase. Cohort studies that met the inclusion and exclusion criteria were selected. The quality of the included literature was evaluated using the Newcastle-Ottawa Scale, and all statistical analyses were performed with R version 4.2.2. The effect size (ES) was measured by the hazard ratio (HR) of overall survival (OS). The OS rates at 3, 6, 12, and 24 months of patients with BM were compared between those with GPAs of 1.5-2.5, 3.0, and 3.5-4.0 and those with GPAs of 0-1 after WBRT.

Results

A total of 1,797 participants who underwent WBRT were included in this study. The meta-analysis revealed a significant association between GPA and OS rates after WBRT: compared with BM patients with GPA of 0-1, 3-month OS rates after WBRT were significantly higher in BM patients with GPA of 1.5-2.5 (HR = 0.48; 95% CI: 0.40-0.59), GPA of 3 (HR = 0.38; 95% CI: 0.25-0.57), and GPA of 3.5-4 (HR = 0.28; 95% CI: 0.15-0.52); 6-month OS rates after WBRT were significantly higher in BM patients with GPA of 1.5-2.5 (HR = 0.48; 95% CI: 0.41-0.56), GPA of 3 (HR = 0.33; 95% CI: 0.24-0.45), and GPA of 3.5-4 (HR = 0.24; 95% CI: 0.16-0.35); 12-month OS rates after WBRT were significantly higher in BM patients with GPA of 1.5-2.5 (HR = 0.49; 95% CI: 0.41-0.58), GPA of 3 (HR = 0.48; 95% CI: 0.32-0.73), and GPA of 3.5-4 (HR = 0.31; 95% CI: 0.12-0.79); and 24-month OS rates after WBRT were significantly higher in BM patients with GPA of 1.5-2.5 (HR = 0.49; 95% CI: 0.42-0.58), GPA of 3 (HR = 0.49; 95% CI: 0.32-0.74), and GPA of 3.5-4 (HR = 0.38; 95% CI: 0.15-0.94).

Conclusion

BM patients with higher GPAs generally exhibited better prognoses and survival outcomes after WBRT compared to those with lower GPAs.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023422914.

Volumetric-Modulated Arc-Based Re-radiosurgery With Simultaneous Reduced-Dose Whole-Brain Irradiation for Local Failures Following Prior Radiosurgery of Brain Oligometastases From Small Cell Lung Cancer

First-line and possibly repeated stereotactic radiosurgery (SRS) with preserving whole-brain radiotherapy (WBRT) is an attractive and promising option for synchronous or metachronous limited brain metastases (BMs) from small cell lung cancer (SCLC), for which a modest prescription dose is generally preferred, such as a biological effective dose of ≤60 Gy, based on the linear-quadratic formula with an alpha/beta ratio of 10 (BED10). In addition, the optimal planning scheme for re-SRS for local progression after SRS of BMs from SCLC remains unclear. Herein, we describe a case of limited BMs developing after a partial response to standard chemoradiotherapy (CRT) for limited-stage SCLC. The BMs, including local failures following prior single-fraction (fr) SRS, were re-treated with volumetric-modulated arc-based SRS combined with simultaneous reduced-dose WBRT. The first SRS with 36.3 Gy/3 fr (BED10 80 Gy) for a small BM resulted in a local control of 17.2 months. However, the second SRS with 20 Gy/1 fr (BED10 60 Gy) to the 60% or 85% isodose surface (IDS) covering the gross tumor volume (GTV) of three new BMs with a paradoxical T1/T2 mismatch, that is, a visible mass on T2 larger than an enhancing area, resulted in partial symptomatic local progression of all lesions within 5.2 months, along with the development of two new lesions, despite continued amrubicin monotherapy. In contrast, the third SRS with 53 Gy/10 fr (BED10 81 Gy) to ≤74% IDSs encompassing the GTV boundary resulted in complete responses of all the lesions during six months. However, despite a combined use of WBRT of 25 Gy in the third SRS, symptomatic spinal cerebrospinal fluid dissemination and new BMs developed, the former leading to patient mortality. A BED10 of ≥80 Gy to the GTV margin and a steep dose increase inside the GTV boundary are suitable to ensure excellent local control in SRS for SCLC BMs. Re-SRS with the aforementioned scheme can be an efficacious option for local failures following prior SRS with a BED10 of ≤60 Gy. Modest dose escalation with a simultaneous integrated boost to bulky lesions in the initial CRT may reduce the development of new BM through improved control of the potential source.

Stereotactic body radiotherapy for extra-cranial oligoprogressive or oligorecurrent small-cell lung cancer

Introduction

The role of local ablative treatments, including stereotactic body radiotherapy (SBRT), is an area of active research in oligometastatic patients. Small cell lung cancer (SCLC) has a poor prognosis, with common diffuse metastatic evolution. We evaluated the outcomes after SBRT in uncommon oligoprogressive/oligorecurrent SCLC presentation.

Methods

Data of SCLC patients who received SBRT for oligoprogressive/oligorecurrent metastatic disease at four centers were retrospectively analyzed. Patients with synchronous oligometastatic disease, SBRT for primary lung tumor and brain radiosurgery were not included. Relapse and survival rates were defined as the time between the date of SBRT and the first event.

Results

Twenty patients (60% with initially limited-disease [LD]) presenting 24 lesions were identified. Oligoprogression and oligorecurrence were observed in 6/20 (30%) and 14/20 (70%) patients, respectively. SBRT was delivered to one (n = 16) to two (n = 4) lesions (median size, 26 mm), mainly to lung [n = 17/24] metastases. At a median follow-up of 2.9 years, no local relapse was observed and 15/20 patients experienced a distant relapse (DR). The median DR and OS were 4.5 months (95 %CI: 2.9-13.7 months) and 17.2 months (95 %CI: 7.5-65.2 months), respectively. The 3-year distant control and OS rates were 25% (95 %CI: 6-44%) and 37% (95 %CI: 15-59%), respectively. Initial LD (vs extensive-disease) was the only prognosis factor associated with a lower risk of post-SBRT DR (HR: 0.3; 95% CI: 0-0.88; p = 0.03). There was no severe observed SBRT-related toxicities.

Conclusion

Prognosis was poor, with DR occurring in most patients. However, local control was excellent and long term response after SBRT may rarely occur in patients with oligoprogressive/oligorecurrent SCLC. Local ablative treatments should be discussed in a multidisciplinary setting on well-selected cases.

Building Team Medicine in the Management of CNS Metastases

CNS metastases are often terminal for cancer patients and occur at an approximately 10-fold higher rate than primary CNS tumors. The incidence of these tumors is approximately 70,000-400,000 cases annually in the US. Advances that have occurred over the past two decades have led to more personalized treatment approaches. Newer surgical and radiation techniques, as well as targeted and immune therapies, have enanled patient to live longer, thus increasing the risk for the development of CNS, brain, and leptomeningeal metastases (BM and LM). Patients who develop CNS metastases have often been heavily treated, and options for future treatment could best be addressed by multidisciplinary teams. Studies have indicated that patients with brain metastases have improved survival outcomes when cared for in high-volume academic institutions using multidisciplinary teams. This manuscript discusses a multidisciplinary approach for both parenchymal brain metastases as well as leptomeningeal metastases implemented in three academic institutions. Additionally, with the increasing development of healthcare systems, we discuss optimizing the management of CNS metastases across healthcare systems and integrating basic and translational science into our clinical care to further improve outcomes. This paper summarizes the existing therapeutic approaches to the treatment of BM and LM and discusses novel and emerging approaches to optimizing access to neuro-oncologic care while simultaneously integrating multidisciplinary teams in the care of patients with BM and LM.

Neurologic Complications of Cancer Treatment

OBJECTIVE

Advances in cancer treatment have led to extended survival and increased risk of neurologic complications in an aging population. This review summarizes potential neurologic complications in patients who have undergone treatment for neurologic and systemic malignancies.

LATEST DEVELOPMENTS

Radiation and cytotoxic chemotherapy along with other targeted therapies continue to be the mainstay of cancer treatment. These advances in cancer care have led to improved outcomes and increased the need to understand the spectrum of neurologic complications that may arise from treatment. While radiation and older therapies including cytotoxic chemotherapies have side effect profiles that are widely known and well understood, this article serves as a review of the more commonly associated neurologic complications of both traditional and newer treatments being offered to this patient population.

ESSENTIAL POINTS

Neurotoxicity is a common complication of cancer-directed treatment. In general, neurologic complications of radiation therapy are more common in central nervous system malignancies, and neurologic complications of chemotherapy are more common in non-neurologic malignancies. Attempts at prevention, early detection, and intervention remain paramount in the reduction of neurologic morbidity.

Brain Metastases: Is There Still a Role for Whole-Brain Radiation Therapy?

Whole-brain radiation therapy (WBRT) has commonly been prescribed to palliate symptoms from brain metastases, to reduce the risk of local relapse after surgical resection, and to improve distant brain control after resection or radiosurgery. While targeting micrometastases throughout the brain can be considered advantageous, the simultaneous exposure of healthy brain tissue might cause adverse events. Attempts to mitigate the risk of neurocognitive decline after WBRT include the selective avoidance of the hippocampi, among others. Besides selective dose reduction, dose escalation to boost volumes, for example, simultaneous integrated boost, aiming at increased tumor control probability is technically feasible. While up-front radiotherapy for newly diagnosed brain metastases often employs radiosurgery or other techniques targeting visible lesions only, sequential (delayed) salvage treatment with WBRT might still become necessary. In addition, the presence of leptomeningeal tumors or very widespread parenchymatous brain metastases might prompt clinicians to prescribe early WBRT.

Somatostatin Receptor-Directed PET/CT for Therapeutic Decision-Making and Disease Control in Patients Affected With Small Cell Lung Cancer

BACKGROUND

Somatostatin receptor (SSTR)-targeted PET/CT is used for patients affected with small cell lung cancer (SCLC), but the clinical impact has not been elucidated yet. We aimed to determine whether SSTR PET/CT can trigger relevant therapeutic management changes in patients with SCLC and whether those modifications achieve disease control and are associated with prolonged survival.

METHODS

One hundred patients with SCLC received SSTR PET/CT. In a retrospective setting, we evaluated the diagnostic performance of PET versus CT and compared therapies before and after PET/CT to determine the impact of molecular imaging on treatment decision. We also determined the rate of disease control after therapeutic modifications and assessed survival in patients with and without changes in the therapeutic regimen.

RESULTS

Relative to CT, SSTR PET alone was superior for assessing bone lesions in 19 of 39 instances (49%). Treatment was modified in 59 of 100 (59%) after SSTR PET/CT. Forty of 59 (74.6%) received systemic treatment after hybrid imaging, with the remaining 15 of 59 (25.4%) scheduled for nonsystemic therapy. In the latter group, 13 of 15 (86.7%) received local radiation therapy or active surveillance (2/15 [13.3%]). Individuals scheduled for systemic treatment after imaging received peptide receptor radionuclide therapy (PRRT) in 28 of 44 (63.6%), followed by chemotherapy in 10 of 44 (22.7%), change in chemotherapy regimen in 3 of 44 (6.8%), and initiation of tyrosine kinase inhibitor in the remaining 3 of 44 (6.8%). Among patients with modified treatment, follow-up was available in 53 subjects, and disease control was achieved in 14 of 53 (26.4%). However, neither change to systemic treatment (155 days; hazard ratio, 0.94; 95% confidence interval, 0.53-1.67) nor change to nonsystemic treatment (210 days; hazard ratio, 0.67; 95% confidence interval, 0.34-1.34) led to a prolonged survival when compared with subjects with no change (171 days, P ≥ 0.22, respectively).

CONCLUSIONS

In patients with SCLC, SSTR-targeted hybrid imaging provides complementary information on the disease status. PET/CT led to management changes in 59% (mainly PRRT), achieving disease control in >26%. The high fraction of patients scheduled for PRRT may lay the foundation for combination strategies to achieve synergistic antitumor effects, for example, by combining PRRT plus recently introduced RNA polymerase II inhibitors.

External Validation of the Graded Prognostic Assessment in Patients with Brain Metastases from Small Cell Lung Cancer

BACKGROUND

Recently, graded prognostic assessment (GPA) for small cell lung cancer (SCLC) patients with brain metastases has been developed. This includes age, performance status, number of brain metastases and presence of extracranial metastases. The aim of the present study was to validate this four-tiered prognostic score in a European cohort of patients.

METHODS

The retrospective validation study included 180 patients from two centers in Germany and Norway.

RESULTS

Median survival from radiological diagnosis of brain metastases was 7 months. The GPA point sum as continuous variable (0-4 points) was significantly associated with survival (p < 0.001). However, no significant survival difference was observed between patients in the two strata with better survival (3.5-4 and 2.5-3 points, respectively). Long-term survival in the poor prognosis group (0-1 points) was better than expected.

CONCLUSION

This study supports the prognostic impact of all four parameters contributing to the GPA. The original way of grouping the parameters and breaking the final strata did not give optimal results in this cohort. Therefore, additional validation databases from different countries should be created and evaluated.

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.

Radiation therapy for extensive-stage small-cell lung cancer in the era of immunotherapy

Unlike non-small-cell lung cancer (NSCLC), the progression of small-cell lung cancer (SCLC) is slow. Extensive-stage SCLC (ES-SCLC) is a serious threat to human health, with a 5-year survival rate of <7%. Chemotherapy has been the first-line treatment for the past 30 years. The anti-PD-L1 checkpoint blockades durvalumab and atezolizumab have greatly prolonged overall survival and have become the standard first-line therapy for ES-SCLC since the CASPIAN and IMpower133 trials. In the era of chemotherapy, radiation therapy (RT), including thoracic radiation therapy (TRT) and brain radiation therapy (BRT), has shown clinical effects in randomized and retrospective studies on ES-SCLC. RT-immunotherapy has shown exciting synergistic effects in NSCLC. For ES-SCLC, the clinical effects of combining TRT/BRT with immunotherapy have not yet been systematically explored. In this review, we found that studies on RT-immunotherapy in ES-SCLC are relatively few and limited to early phase studies focusing on toxicity. The efficacy and safety profiles of early phase studies encourage prospective clinical trials. In this review, we discuss the best population, optimum TRT dose, proper TRT time, and strategies for reducing radiation-induced neurotoxicity. Furthermore, we suggest that biomarkers and patient performance status should be fully assessed before RT-immunotherapy treatment. Prospective trials are needed to provide more evidence for RT-immunotherapy applications in ES-SCLC.