Re-examining prophylactic cranial irradiation in small cell lung cancer: a systematic review and meta-analysis

Background

Patients with small cell lung cancer (SCLC) are at high risk for brain metastases. Prophylactic cranial irradiation (PCI) is recommended in this population to reduce the incidence of brain metastases and prolong survival. We aimed to assesses the efficacy of PCI in this population in the era of routine brain imaging. To our knowledge, this is the first systematic review and meta-analysis to examine the use among patients who were radiographically confirmed not to have brain metastases after completion of first-line therapy.

Methods

In this systematic review and meta-analysis, cohort studies and controlled trials reporting on the use of PCI for patients SCLC were identified in EMBASE, MEDLINE, CENTRAL, and grey literature sources. The literature search was conducted on November 12, 2023. Summary data were extracted. Random-effects meta-analyses pooled hazard ratios (HR) for the primary outcome of overall survival between PCI and no intervention groups. This study is registered with the Open Science Framework, DOI:10.17605/OSF.IO/BC359, and PROSPERO, CRD42021249466.

Findings

Of 4318 identified records, 223 were eligible for inclusion. 109 reported on overall survival in formats amenable to meta-analysis; PCI was associated with longer survival in all patients with SCLC (HR 0.59; 95% CI, 0.55-0.63; p < 0.001; n = 56,770 patients), patients with limited stage disease (HR 0.60; 95% CI, 0.55-0.65; p < 0.001; n = 78 studies; n = 27,137 patients), and patients with extensive stage disease (HR 0.59; 95% CI, 0.51-0.70; p < 0.001; n = 28 studies; n = 26,467 patients). Between-study heterogeneity was significant when pooled amongst all studies (I2 = 73.6%; 95% CI 68.4%-77.9%). Subgroup analysis did not reveal sources of heterogeneity. In a subgroup analysis on studies that used magnetic resonance imaging to exclude presence of brain metastases at restaging among all patients, overall survival did not differ significantly between patients who did or did not receive PCI (HR 0.74; 95% CI, 0.52-1.05; p = 0.08; n = 9 studies; n = 1384 patients).

Interpretation

Our findings suggested that administration of PCI is associated with a survival benefit, but not when considering studies that radiographically confirmed absence of brain metastases, suggesting that the survival benefit conferred by PCI might be therapeutic rather than prophylactic.

Funding

No funding.

Association of Brain Metastases With Survival in Patients With Limited or Stable Extracranial Disease: A Systematic Review and Meta-analysis

IMPORTANCE

Intracranial metastatic disease (IMD) is a severe complication of cancer with profound prognostic implications. Patients with IMD in the setting of limited or stable extracranial disease (IMD-SE) may represent a unique and understudied subset of patients with IMD with superior prognosis.

OBJECTIVE

To evaluate overall survival (OS), progression-free survival (PFS), and intracranial PFS (iPFS) in patients with IMD-SE secondary to any primary cancer.

DATA SOURCES

Records were identified from MEDLINE, EMBASE, CENTRAL, and gray literature sources from inception to June 21, 2021.

STUDY SELECTION

Studies in English reporting OS, PFS, or iPFS in patients with IMD-SE (defined as IMD and ≤2 extracranial metastatic sites) and no prior second-line chemotherapy or brain-directed therapy were selected.

DATA EXTRACTION AND SYNTHESIS

Author, year of publication, type of study, type of primary cancer, and outcome measures were extracted. Random-effects meta-analyses were performed to estimate effect sizes, and subgroup meta-analysis and metaregression were conducted to measure between-study differences in February 2022.

MAIN OUTCOMES AND MEASURES

The primary end point was OS described as hazard ratios (HRs) and medians for comparative and single-group studies, respectively. Secondary end points were PFS and iPFS.

RESULTS

Overall, 68 studies (5325 patients) were included. IMD-SE was associated with longer OS (HR, 0.52; 95% CI, 0.39-0.70) and iPFS (HR, 0.63; 95% CI, 0.52-0.76) compared with IMD in the setting of progressive extracranial disease. The weighted median OS estimate for patients with IMD-SE was 17.9 months (95% CI, 16.4-22.0 months), and for patients with IMD-PE it was 8.0 months (95% CI, 7.2-12.8 months). Pooled median OS for all patients with IMD-SE was 20.9 months (95% CI, 16.35-25.98 months); for the subgroup with breast cancer it was 20.2 months (95% CI, 10.43-38.20 months), and for non-small cell lung cancer it was 27.5 months (95% CI, 18.27-49.66 months). Between-study heterogeneity for OS and iPFS were moderate (I2 = 56.5%) and low (I2 = 0%), respectively.

CONCLUSIONS AND RELEVANCE

In this systematic review and meta-analysis of patients with IMD-SE, limited systemic disease was associated with improved OS and iPFS. Future prospective trials should aim to collect granular information on the extent of extracranial disease to identify drivers of mortality and optimal treatment strategies in patients with brain metastases.

Failure of human rhombic lip differentiation underlies medulloblastoma formation

Medulloblastoma (MB) comprises a group of heterogeneous paediatric embryonal neoplasms of the hindbrain with strong links to early development of the hindbrain^1-4. Mutations that activate Sonic hedgehog signalling lead to Sonic hedgehog MB in the upper rhombic lip (RL) granule cell lineage^5-8. By contrast, mutations that activate WNT signalling lead to WNT MB in the lower RL^9,10. However, little is known about the more commonly occurring group 4 (G4) MB, which is thought to arise in the unipolar brush cell lineage^3,4. Here we demonstrate that somatic mutations that cause G4 MB converge on the core binding factor alpha (CBFA) complex and mutually exclusive alterations that affect CBFA2T2, CBFA2T3, PRDM6, UTX and OTX2. CBFA2T2 is expressed early in the progenitor cells of the cerebellar RL subventricular zone in Homo sapiens, and G4 MB transcriptionally resembles these progenitors but are stalled in developmental time. Knockdown of OTX2 in model systems relieves this differentiation blockade, which allows MB cells to spontaneously proceed along normal developmental differentiation trajectories. The specific nature of the split human RL, which is destined to generate most of the neurons in the human brain, and its high level of susceptible EOMES⁺KI67⁺ unipolar brush cell progenitor cells probably predisposes our species to the development of G4 MB.

SYST-03 INCIDENCE AND SURVIVAL OF PATIENTS WITH INTRACRANIAL METASTATIC DISEASE AND ERBB2-POSITIVE GASTROINTESTINAL CANCERS: A RETROSPECTIVE COHORT STUDY

BACKGROUND

Intracranial metastatic disease (IMD) is a mortality-driving complication of gastrointestinal (GI) cancers. In breast cancer, ERBB2 positivity is associated with shorter overall survival (OS) and increased risk of IMD, and while ERBB2 status is relevant in primary GI cancer, no study has directly assessed the relationship of ERBB2 status and IMD in these patients.

METHODS

Records for adult patients with GI cancer and IMD, treated with ERBB2-therapy between 2005 and 2018 were retrieved from ICES. Baseline characteristics were compared between subcohorts stratified by IMD and ERBB2 statuses. Kaplan-Meier and Cox regression analyses were performed to estimate survival.

RESULTS

Records for 99,256 patients with GI cancer were collected, and IMD was diagnosed in 2002 patients. The highest IMD incidence rate was among patients with esophageal cancer (5.5%). Among patients with ERBB2+ disease, 306 had gastric (9 IMD), 168 esophageal (15 IMD), and 17 colorectal cancer. Diagnosis of IMD was associated with shorter OS among patients with colorectal (HR 3.0; 95% CI 2.9–3.2), gastric (HR 1.7; 95% CI, 1.5–1.9), and esophageal cancers (HR 1.2; 95% CI, 1.1–1.4). Post-IMD ERBB2-targeted therapy was not associated with OS among patients with ERBB2+ esophageal (HR 0.5; 95% CI, 0.2–1.2; n = 15) or gastric cancer (HR 0; 95% CI 0–Inf; n = 9).

CONCLUSION

Our study assessed patients with ERBB2+ GI cancer and IMD. Diagnosis of IMD was associated with shorter survival in gastric, esophageal, and colorectal cancers. Post-IMD ERBB2 therapy was not associated with OS, and IMD diagnosis was associated with prolonged survival in patients with stage 4 ERBB2+ disease, although interpretation of these results is complicated by small sample size and selection bias. Our results motivate increased reporting and inclusion of patients with ERBB2+ GI cancers in clinical trials.

Brain metastases in the setting of stable extracranial disease: A systematic review and meta-analysis

2022

Background: Intracranial metastatic disease (IMD) is a life-altering complication for many patients with cancer. Improvements in systemic therapies have transformed the epidemiology of IMD, with some patients presenting with IMD in the context of stable extracranial disease (IMD-SECD). Among patients with metastases in other sites with similarly stable systemic disease, surgical resection and targeted therapy can result in long-term disease control and extended overall survival (OS), yet little is known about the clinical outcomes for patients with IMD-SECD. Methods: We searched MEDLINE, EMBASE, CENTRAL, and grey literature sources up to June 21, 2021 for studies reporting brain metastasis (BrM) with controlled extracranial disease (ECD) as well as IMD-SECD secondary to any primary cancer (criteria: presence of BrM and ≤2 extracranial metastatic sites, with no prior second-line chemotherapy and second-line brain-directed therapy). In studies comparing IMD-SECD and IMD patients, hazard ratios (HR) for OS and intracranial progression-free survival (iPFS) were pooled using random-effects meta-analysis, while medians for OS were estimated from single-arm IMD-SECD studies based on distribution-free summary survival curves. Results: Of 1067 records identified, 68 studies involving 5325 patients with IMD-SECD were included. Patients with IMD-SECD had prolonged OS (HR 1.93; 95% CI, 1.44-2.59; n = 10 studies; n = 877 patients) and iPFS (HR 1.59; 95% CI 1.31-1.92; n = 4 studies; n = 673 patients) compared with IMD patients. Subgroup analysis of patients with BrM and controlled versus uncontrolled ECD found prolonged OS with controlled ECD (HR 2.46; 95% CI, 1.36-4.44; n = 4 studies; n = 135 patients). Pooled median OS for all IMD-SECD patients was 20.85 months (mo) (95% CI, 16.35-25.98; n = 27 studies; n = 2159 patients). Stratification by primary cancer type showed median OS 20.18 mo (95% CI, 10.43-38.20; n = 2 studies; n = 109 patients) and 27.46 mo (95% CI, 18.27-49.66; n = 13 studies; n = 497 patients) for patients with IMD-SECD secondary to breast cancer and non-small cell lung cancer, respectively. Conclusions: Patients with IMD-SECD demonstrate prolonged OS and iPFS compared with patients with IMD, who may have more extensive systemic disease. Our results suggest that patients with IMD-SECD may represent a distinct subpopulation of patients with IMD with a uniquely favourable prognosis. It is possible that aggressive and timely treatment may significantly prolong survival for these patients. Future prospective trials should aim to investigate the efficacy of current treatment regimens in patients with IMD-SECD to further clarify optimal treatment pathways in this unique population of patients.

Stereotactic radiosurgery (SRS) versus whole brain radiation therapy (WBRT) in patients with small cell lung cancer (SCLC) and intracranial metastatic disease (IMD): A systematic review and meta-analysis

8570

Background: Patients with SCLC are at high risk for the development of IMD and, subsequently, rapid intracranial progression. SRS has supplanted WBRT as first-line treatment for IMD in most solid cancers, but WBRT remains first-line treatment for IMD in SCLC patients. Data on SRS in SCLC are limited to small retrospective studies. Methods: Studies reporting on SRS in SCLC patients with IMD were collected from EMBASE, MEDLINE, CENTRAL, and grey literature sources (n = 3,732 studies). Random-effects meta-analysis pooled hazard ratios (HR) for overall survival (OS) between SRS and WBRT ± SRS boost, as well as medians for OS in months (mo) and risk rates for intracranial local (LC) and intracranial distant control (DC) in single-arm SRS studies. Results: OS following SRS was non-inferior compared with WBRT ± SRS boost (HR 0.90; 95% confidence interval (95CI), 0.73-1.10; n = 7 studies; n = 18,130 patients), and superior compared with WBRT alone (HR 0.80; 95CI, 0.66-0.96; n = 7 studies; n = 16,961 patients). Pooled median OS from single-arm studies following SRS was 8.99 mo (95CI, 7.86-10.15; n = 14 studies; n = 1,682 patients). Pooled LC and DC estimates following SRS were 81% (95CI, 67%-99%) and 66% (95CI, 50%- 86%), respectively, at 6 mo, and 78% (95CI, 61%-98%) and 58% (95CI, 46%-75%), respectively, at 12 mo. Conclusions: This systematic review and meta-analysis provides evidence that SRS may achieve analogous survival outcomes compared with WBRT in patients with SCLC and IMD, indicating that a subset of SCLC patients may benefit from first-line SRS treatment. Prospective trials should investigate the impact of metastatic burden as well as LC and DC differences between WBRT- and SRS-treated SCLC patients.

Assessing the Association of Targeted Therapy and Intracranial Metastatic Disease

Importance

Targeted therapies have been hypothesized to prolong survival in the treatment of patients with intracranial metastatic disease (IMD) but, paradoxically, increase IMD incidence by improving systemic disease control and prolonging survival from the primary tumor. The real-world benefits of targeted therapy in treating patients with IMD are unclear, as clinical trials have excluded patients with IMD and lacked end points that report intracranial outcomes.

Objective

To assess the association of targeted therapy and IMD with patient survival.

Design, Setting, and Participants

This retrospective cohort study included all patients in Ontario, Canada, who received a diagnosis of IMD from April 2005 to January 2018 with primary diagnoses of breast cancer, lung or bronchus cancer, or melanoma and control patients who were matched by primary disease without IMD. The data were analyzed between March and October 2020.

Exposures

EGFR-, ERBB2 (HER2-), or BRAF-targeted therapy or IMD status.

Main Outcomes and Measures

Kaplan-Meier and multivariable Cox regression analyses were performed to compare overall survival (OS) between patient subcohorts divided by primary disease and stratified by targeted therapy receipt or IMD status.

Results

In this cohort of 26 676 patients with IMD and breast cancer, lung and bronchus cancer, or melanoma, 57% of patients were women, and the median age at IMD diagnosis was 64 years (interquartile range, 56-72 years). Post-IMD targeted therapy was associated with prolonged OS in patients with ERBB2-positive breast cancer (hazard ratio [HR], 0.41; 95% CI, 0.33-0.50), EGFR-positive lung cancer (HR, 0.28; 95% CI, 0.23-0.34), and BRAF-positive melanoma (HR, 0.20; 95% CI, 0.14-0.29) compared with those who did not receive post-IMD targeted therapy. The presence of IMD was associated with shorter OS in patients with metastatic ERBB2-positive breast cancer (HR, 1.80; 95% CI, 1.56-2.08) and metastatic EGFR-positive lung cancer (HR, 1.22; 95% CI, 1.08-1.39) but not metastatic BRAF-positive melanoma (HR, 1.11; 95% CI, 0.77-1.61) compared with those without IMD.

Conclusions and Relevance

The findings of this cohort study suggest an association between real-world use of targeted therapies and prolonged OS in patients with IMD in the setting of ERBB2-positive breast cancer, EGFR-positive lung cancer, and BRAF-positive melanoma. Including patients with IMD in clinical trials and using end points that interrogate IMD will be critical to determine the role of targeted therapies in treating patients with IMD.

Assessment of Effectiveness and Safety of Osimertinib for Patients With Intracranial Metastatic Disease: A Systematic Review and Meta-analysis

Importance

Intracranial metastatic disease (IMD) is a serious and life-altering complication for many patients with cancer. Targeted therapy may address the limitations of current treatments as an additional agent to achieve intracranial disease control in some patients with IMD. Given the paucity of evidence regarding effectiveness, current guidelines have not made recommendations on the use of targeted therapy. Osimertinib mesylate is a mutant epidermal growth factor receptor (EGFR) inhibitor that can penetrate the blood-brain barrier and inhibit tumor cell survival and proliferation in patients with non-small cell lung cancer (NSCLC) with specific EGFR alterations.

Objective

To assess the effectiveness and safety of osimertinib in the management of IMD.

Data Sources

Studies were selected from MEDLINE and Embase databases from their inception to September 20, 2019, using the following search query: (osimertinib OR mereletinib OR tagrisso OR tamarix OR azd9291) AND (brain metastases OR intracranial metastatic disease OR cns).

Study Selection

Studies reporting intracranial outcomes for patients with metastatic EGFR-variant NSCLC and IMD treated with osimertinib were included in this systematic review and meta-analysis. Among 271 records identified in the systematic review, 15 studies fulfilled eligibility criteria for inclusion in the meta-analysis.

Data Extraction and Synthesis

Data were extracted from published studies and supplements. These data were pooled using a random-effects model. Risk of bias was assessed using the Cochrane risk of bias tool and the modified Newcastle-Ottawa Scale.

Main Outcomes and Measures

Information extracted included study characteristics, intracranial effectiveness measures, and safety measures. Meta-analyses of proportions were conducted to pool estimates for central nervous system (CNS) objective response rate and CNS disease control rate.

Results

Fifteen studies reporting on 324 patients were included in the meta-analysis. The CNS objective response rate was 64% (95% CI, 53%-76%; n = 195), and CNS disease control rate was 90% (95% CI, 85%-93%; n = 246). Included studies reported complete intracranial response rates of 7% to 23%, median best decrease in intracranial lesion size of -40% to -64%, and Common Terminology Criteria for Adverse Events (version 3.0) grade 3 or higher adverse event rates of 19% to 39%. Subgroup analyses did not reveal additional sources of heterogeneity.

Conclusions and Relevance

Findings reported herein support a potential role for osimertinib in the treatment of patients with metastatic EGFR-variant NSCLC and IMD treated with osimertinib. Clinical decision makers would benefit from the inclusion of patients with IMD in future trials to identify factors that predict responses to targeted therapy.

HER2-targeted therapy prolongs survival in patients with HER2-positive breast cancer and intracranial metastatic disease: a systematic review and meta-analysis

BACKGROUND

Intracranial metastatic disease (IMD) is a serious and known complication of human epidermal growth factor receptor 2 (HER2)-positive breast cancer. The role of targeted therapy for patients with HER2-positive breast cancer and IMD remains unclear. In this study, we sought to evaluate the effect of HER2-targeted therapy on IMD from HER2-positive breast cancer.

METHODS

We searched MEDLINE, EMBASE, CENTRAL, and gray literature sources for interventional and observational studies reporting survival, response, and safety outcomes for patients with IMD receiving HER2-targeted therapy. We pooled outcomes through meta-analysis and examined confounder effects through forest plot stratification and meta-regression. Evidence quality was evaluated using GRADE (PROSPERO CRD42020161209).

RESULTS

A total of 97 studies (37 interventional and 60 observational) were included. HER2-targeted therapy was associated with prolonged overall survival (hazard ratio [HR] 0.47; 95% confidence interval [CI], 0.39-0.56) without significantly prolonged progression-free survival (HR 0.52; 95% CI, 0.27-1.02) versus non-targeted therapy; the intracranial objective response rate was 19% (95% CI, 12-27%), intracranial disease control rate 62% (95% CI, 55-69%), intracranial complete response rate 0% (95% CI, 0-0.01%), and grade 3+ adverse event rate 26% (95% CI, 11-45%). Risk of bias was high in 40% (39/97) of studies.

CONCLUSION

These findings support a potential role for systemic HER2-targeted therapy in the treatment of patients with IMD from HER2-positive metastatic breast cancer.

The Impact of Targeted Therapy on Intracranial Metastatic Disease Incidence and Survival

Intracranial metastatic disease (IMD) is a common and severe complication of primary cancers. Current treatment options for IMD include surgical resection and radiation therapy, although there has been recent interest in targeted therapy in the management of IMD. As of yet, insufficient data exist to support the recommendation of targeted therapies in the treatment of IMD. Paradoxically, targeted therapy has been hypothesized to play a role in the development of IMD in patients with primary cancers. This is based on the observations that patients who receive targeted therapy for primary cancer experience prolonged survival, and that prolonged survival has been associated with increased incidence of IMD. Few data exist to clarify if treatment of primary cancers with targeted therapies influences IMD incidence. Here, we discuss the role of targeted therapy in IMD management, review the current literature on IMD incidence and targeted therapy use in primary cancer, and propose the need for future studies to inform physicians in choosing treatment options and counseling patients.

Fine structure of seminiferous tubules in antarctic seals

The fine structure of seminiferous tubules from 5 crabeater, 2 leopard and 2 Ross seals showed that during the nonbreeding season the tubules were essentially similar in possessing spermatogenic and Sertoli cells. However, the tubules of leopard and Ross seals had more primary and secondary spermatocytes and spermatids than the crabeater seals. In general, the tubules were devoid of spermatozoa. The spermatids showed stages of maturation such as Golgi phase of acrosome formation, acrosomal cap formation and condensation of nuclei. Some spermatids degenerated in tubules. Both maturing and degenerating spermatids were closely associated with Sertoli cells. Junctional complexes with plaques of filaments were observed between Sertoli cells and the spermatogenic cells. Sertoli cells, irregular and polygonal, contained highly convoluted nuclei, strands of rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi complexes, small mitochondria, variable amounts of lipid droplets, lysosomes, lipofuscin granules and highly plicated plasma membranes. In brief, the spermatogenic activity had practically ceased in the testes and the animals probably secreted low levels of testosterone during the nonbreeding season.

Parasites of wolves, Canis lypus L., in northeastern Minnesota, as indicated by analysis of fecal samples

Two hundred and four scat fragments of wolves (Canis lupus) were collected from December 1969 through August 1971 in northeastern Minnesota; 74 of these contained parasite ova or larvae. Helminths representing the following genera were identified: (Trematoda) Alaria; (Cestoda) Moniezia and Taeniidae gen.indet.; (Nematoda) Ancylostoma, Uncinaria, Trichuris, Capillaria, Toxocara, and Filaroides. Oocysts of sporozoa of the family Eimeriidae also were observed. The occurrence of Alaria, Ancylostoma, Trichuris, Toxocara, and Capillaria in Minnesota wolves has not been reported previously. The ecological significance of these parasites is discussed.

Fine structure of Leydig cells in crabeater, leopard and Ross seals

Ultrastructural study of the Leydig cells of nonbreeding crabeater, leopard and Ross seals showed that three types of cells could be distinguished. Type I cells possessed the cytological features typical of steroid-secreting cells. Type II cells exhibited various features of degeneration, e.g. accumulation of large amounts of lipofuscin granules (residual bodies), lipid droplets, secondary lysosomes, rectangular crystalloids, and previously undescribed 'peculiar bodies'. These cellular inclusions and debris were released into the interstitium to be phagocytosed by macrophages and/or resorbed by the lymphatics. Type III Leydig cells contained large amounts of lipid droplets, sparse cytoplasmic organelles and essentially became lipid storage cells.