Linac-based stereotactic radiosurgery and fractionated stereotactic radiotherapy with a micro-multileaf collimator for brain metastasis in the primary motor cortex

Surgical resection versus stereotactic radiosurgery for the treatment of brain metastases in the motor cortex; a meta-analysis and systematic review

Brain metastasis in the motor cortex is a challenging condition to treat. Surgical resection or stereotactic radiosurgery (SRS)/hypofractionated stereotactic radiotherapy (hypoSRT) are valuable options up to now. Due to its unique location and potential for neurologic deficits, neither treatment is entirely satisfactory. There is still a lack of data on the treatment result of motor cortex metastasis. This study provides a comprehensive review and meta-analysis comparing surgery and SRS/hypoSRT for treating brain metastasis in the motor cortex. Core databases, including PubMed, Embase, and the Cochrane Library, were systematically searched for brain metastasis in the motor cortex, demonstrating the clinical outcomes of both surgery and SRS/hypoSRT. Motor power outcome and treatment-associated complication rates were thoroughly evaluated. Twenty-five articles were listed for full-text review. Among them, 13 articles were eligible for inclusion criteria: retrospective cohort studies comparing surgery and SRS/hypoSRT. There are 323 patients in the surgery group and 220 in the SRS/hypoSRT group. The motor outcome is better in surgery group, but without statistical significance (0.49 vs 0.37, p = 0.3937) and treatment-related complication is lower in surgery group with statistical significance (0.09 vs 0.26, p = 0.0218). Treatment modality should be tailored by the patient's performance status, history of radiation, presence of ongoing chemotherapy, or extracranial progression status.

Clinical Results and Hematologic Predictors of Linear Accelerator-Based Stereotactic Radiosurgery or Fractionated Stereotactic Radiotherapy for Brain Metastasis in Patients Aged 75 Years or Older: A Retrospective Study

OBJECTIVE

This study aimed to evaluate prognostic factors including pre-radiosurgical blood count in elderly patients (EPs) with brain metastasis (BM) who were treated using linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (fSRT) with a micro-multileaf collimator.

METHODS

Between January 2011 and November 2021, 101 consecutive EPs with BM were treated by LINAC-based SRS or fSRT using LINAC with a micro-multileaf collimator. EPs were defined as patients aged ≥75 years.

RESULTS

The tumors originated from the lungs (n = 90; 89.1%), colon (n = 2; 2.0%), and others (n = 9; 8.8%) in these EPs. The median pretreatment Karnofsky Performance Status was 80 (range, 40-100). The median follow-up time was 10 months (range, 0-76), as was the median survival. The 6-month, 1-year, and 2-year survival in the EP group was 58.3%, 43.2%, and 28.5%, respectively. Freedom from local failure at 6 months and 1 and 2 years was 97%, 95%, and 91.5%, respectively. Freedom from distant failure at 6 months and 1 and 2 years in EPs was 70.6%, 59.4%, and 54.2%, respectively. A high neutrophil/lymphocyte ratio >5.33 was an unfavorable predictor of prognosis for EPs with BMs treated with SRS and fSRT (P < 0.001). In the EPs, the prognostic factors associated with prolonged survival in the Cox proportional hazards model were being female and a good pretreatment Karnofsky Performance Status.

CONCLUSIONS

The findings of our study highlight the efficacy of LINAC-based SRS and fSRT with a micro-multileaf collimator in the treatment of EPs with BMs. Neutrophil/lymphocyte ratio can be an important factor in treatment decisions for EPs with BMs.

Innate Immune System in the Context of Radiation Therapy for Cancer

Radiation therapy (RT) remains an integral component of modern oncology care, with most cancer patients receiving radiation as a part of their treatment plan. The main goal of ionizing RT is to control the local tumor burden by inducing DNA damage and apoptosis within the tumor cells. The advancement in RT, including intensity-modulated RT (IMRT), stereotactic body RT (SBRT), image-guided RT, and proton therapy, have increased the efficacy of RT, equipping clinicians with techniques to ensure precise and safe administration of radiation doses to tumor cells. In this review, we present the technological advancement in various types of RT methods and highlight their clinical utility and associated limitations. This review provides insights into how RT modulates innate immune signaling and the key players involved in modulating innate immune responses, which have not been well documented earlier. Apoptosis of cancer cells following RT triggers immune systems that contribute to the eradication of tumors through innate and adoptive immunity. The innate immune system consists of various cell types, including macrophages, dendritic cells, and natural killer cells, which serve as key mediators of innate immunity in response to RT. This review will concentrate on the significance of the innate myeloid and lymphoid lineages in anti-tumorigenic processes triggered by RT. Furthermore, we will explore essential strategies to enhance RT efficacy. This review can serve as a platform for researchers to comprehend the clinical application and limitations of various RT methods and provides insights into how RT modulates innate immune signaling.

Long-Term Survival after Linac-Based Stereotactic Radiosurgery and Radiotherapy with a Micro-Multileaf Collimator for Brain Metastasis

Background: this study aimed to evaluate the prognostic factors associated with long-term survival after linear accelerator (linac)-based stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (fSRT) with a micro-multileaf collimator for brain metastasis (BM). Methods: This single-center retrospective study included 226 consecutive patients with BM who were treated with linac-based SRS or fSRT with a micro-multileaf collimator between January 2011 and December 2018. Long-term survival (LTS) was defined as survival for more than 2 years after SRS/fSRT. Results: The tumors originated from the lung (n = 189, 83.6%), breast (n = 11, 4.9%), colon (n = 9, 4.0%), stomach (n = 4, 1.8%), kidney (n = 3, 1.3%), esophagus (n = 3, 1.3%), and other regions (n = 7, 3.1%). The median pretreatment Karnofsky performance scale (KPS) score was 90 (range: 40–100). The median follow-up time was 13 (range: 0–120) months. Out of the 226 patients, 72 (31.8%) were categorized in the LTS group. The median survival time was 43 months and 13 months in the LTS group and in the entire cohort, respectively. The 3-year, 4-year, and 5-year survival rate in the LTS group was 59.1%, 49.6%, and 40.7%, respectively. Multivariate regression logistic analysis showed that female sex, a pre-treatment KPS score ≥ 80, and the absence of extracranial metastasis were associated with long-term survival. Conclusions: female sex, a favorable pre-treatment KPS score, and the absence of extracranial metastasis were associated with long-term survival in the current cohort of patients with BM.