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Metastatic cancer is a heterogeneous entity, some of which could benefit from local consolidative radiation therapy (RT). Although randomized evidence is growing in support of using RT for oligometastatic disease, a highly active area of investigation relates to whether RT could benefit patients with polymetastatic disease. This article highlights the preclinical and clinical rationale for using RT for polymetastatic disease, proposes an exploratory framework for selecting patients best suited for these types of treatments, and briefly reviews potential challenges. The goal of this hypothesis-generating review is to address personalized multimodality systemic treatment for patients with metastatic cancer. The rationale for using high-dose RT is primarily for local control and immune activation in either oligometastatic or polymetastatic disease. However, the primary application of low-dose RT is to activate distinct antitumor immune pathways and modulate the tumor stroma in efforts to better facilitate T cell infiltration. We explore clinical cases involving high- and low-dose RT to demonstrate the potential efficacy of such treatment. We then group patients by extent of disease burden to implement high- and/or low-dose RT. Patients with low-volume disease may receive high-dose RT to all sites as part of an oligometastatic paradigm. Subjects with high-volume disease (for whom standard of care remains palliative RT only) could be treated with a combination of high-dose RT to a few sites for immune activation, while receiving low-dose RT to several remaining lesions to enhance systemic responses from high-dose RT and immunotherapy. We further discuss how emerging but speculative concepts such as immune function may be integrated into this approach and examine therapies currently under investigation that may help address immune deficiencies. The review concludes by addressing challenges in using RT for polymetastatic disease, such as concerns about treatment planning workflows, treatment times, dose constraints for multiple-isocenter treatments, and economic considerations.

Background Chimeric Antigen Receptor T-cell therapy (CAR-t) for patients with relapsed or refractory B cell precursor acute lymphoblastic leukemia (ALL) is associated with high overall remission rates but also with significant complications. Cytokine release syndrome (CRS) and Immune Cell Associated Neurotoxicity Syndrome (ICANS) are life-threatening sequelae that may occur in CAR-t recipients. ICANS presents with varying symptoms ranging from confusion to seizure and cerebral edema. There is no consensus on specific biological events that incite ICANS. Blood brain barrier (BBB) permeability is altered in CD19 CAR-t therapy, but the cause of altered BBB permeability is not clear. IL6 targeted interventions that control symptoms of CRS are ineffective against ICANS, suggesting these entities have separate pathologic mechanisms. Criteria for ICANS severity grading and guidelines for supportive care management are published, but there is no universal predictor of ICANS. Identification of manipulable biologic factors to predict the onset of ICANS would represent significant progress for clinical management of ICANS. Methods We collected plasma samples from 12 adult patients with varying ICANS severity following CAR-t therapy, aged 24-74 years. Diagnoses were diffuse large B cell lymphoma (DLBCL), transformed follicular lymphoma (TFL), and primary mediastinal B cell lymphoma (PMBCL) in varying stages of progression or relapse. Pre-CAR-t, midpoint and 7 or 8 day post CAR-t samples were evaluated with multiplex cytokine arrays to quantify relative levels of 105 angiogenic cytokines. Results were compared between two groups: patients who did not develop ICANS (n=5), and patients who developed any grade of ICANS (n=7; 2 patients grade 0-2, 5 patients grade 3-4). Results There was a trend toward higher baseline relative levels of two angiogenic factors, ApoA1 and Angiogenin, in patients with ICANS relative to those without. Interestingly, ApoA1 increased over time in patients who did not develop ICANS; a 320 +/- 56 % increase in ApoA1 occurred from baseline to day 7/8. In contrast, ApoA1 decreased to 88 +/- 25% of baseline by day 7/8 in patients who developed ICANS (No ICANS vs ICANS; p=0.003). Similarly, Angiogenin increased by 289 +/- 77% over baseline by day 7/8 in patients who did not develop ICANS, while it decreased to 98 +/- 24 % of baseline by day 7/8 in patients who developed ICANS (No ICANS vs ICANS, p = 0.03). Conclusion Our data suggests that ApoA1 and Angiogenin levels at baseline, and changes in ApoA1 or Angiogenin over time, may indicate risk of ICANS. This correlation requires validation in a larger patient population as well as quantification of absolute ApoA1 and Angiogenin concentrations in blood. If ApoA1 and Angiogenin baseline levels are indeed correlated with the risk of ICANS, this may represent major progress in clinical management of ICANS.

The histological distribution of gonadotrophs containing either LH or FSH, but not both gonadotropins, has been demonstrated before in the juvenile and adult chicken throughout the caudal and cephalic anterior pituitary lobes. In the present investigation, the distribution of FSH- and/or LH-containing gonadotrophs was further investigated in the chicken embryo by use of the same homologous antibodies as used in our earlier study. Fluorescent dual-labeling immunohistochemistry revealed that during embryogenesis LH and FSH reside exclusively in separate gonadotrophs, as has been described before in the post hatch bird. LH-immunoreactive cells were observed for the first time at day 9 of embryogenesis. This is as much as 4 days earlier than the FSH-immunoreactive cells, which appeared at day 13 of embryogenesis. Our results confirm that FSH- and LH-containing gonadotrophs are distributed throughout both lobes of the anterior pituitary. No conspicuous differences were observed between the sexes in any of the aspects investigated. The described situation is unique in that it seems to imply the existence of separate cell lineages for FSH- and LH-producing cells, as opposed to the single gonadotrope lineage described in all other species studied so far, with the exception of bovine. Our data indeed raise the question as to which signaling and/or transcription factors may cause the unique dichotomy observed in the chicken gonadotrophs.