Neoadjuvant Stereotactic Radiosurgery: a Further Evolution in the Management of Brain Metastases

Stereotactic radiosurgery for brain metastases arising from gynecological malignancies: A retrospective treatment outcome analysis

BACKGROUND

This retrospective study aims to assess the efficacy of stereotactic radiosurgery (SRS) in the treatment of brain metastases (BM) originating from gynecological cancers. It focuses on local control (LC), distant tumor control (DTC), and overall survival (OS).

METHODS

The analysis comprised 18 individuals with gynecological-origin BM treated with SRS at the Hadassah Medical Center from 2004 to 2021. Statistical analyses evaluate factors impacting LC, DTC, and OS.

RESULTS

A total of 36 BM of gynecological origin underwent SRS. The median age at the first SRS treatment was 60 years, with a median time of 24.5 months from the primary malignancy diagnosis to BM detection. The 12-month LC rate per patient was 84.6 %, and 5.6 % per BM. Only two instances of local recurrence were observed. The DTC at 12 months was 75 %, with a 29 % overall. Non-significant trends indicating a correlation with distant brain failure with increased cumulative volume and the occurrence of craniotomy before SRS. The median OS of the cohort was 16.5 months from SRS treatment. The 6, 12, 18, and 24-month survival rates were 77.8 %, 66.7 %, 50 %, and 22.2 % respectively. Higher number of BM was associated with lower OS (p = 0.046). On multivariate analysis, age was a significant factor for OS (p = 0.03), demonstrating that older age was associated with a more favorable prognosis.

CONCLUSION

This study supports SRS effectiveness for treating BM from gynecological cancers and suggests similar outcomes to more common malignancies.

Opportunities and Alternatives of Modern Radiation Oncology and Surgery for the Management of Resectable Brain Metastases

Postsurgical radiotherapy (RT) has been early proven to prevent local tumor recurrence, initially performed with whole brain RT (WBRT). Subsequent to disadvantageous cognitive sequalae for the patient and the broad distribution of modern linear accelerators, focal irradiation of the tumor has omitted WBRT in most cases. In many studies, the effectiveness of local RT of the resection cavity, either as single-fraction stereotactic radiosurgery (SRS) or hypo-fractionated stereotactic RT (hFSRT), has been demonstrated to be effective and safe. However, whereas prospective high-level incidence is still lacking on which dose and fractionation scheme is the best choice for the patient, further ablative techniques have come into play. Neoadjuvant SRS (N-SRS) prior to resection combines straightforward target delineation with an accelerated post-surgical phase, allowing an earlier start of systemic treatment or rehabilitation as indicated. In addition, low-energy intraoperative RT (IORT) on the surgical bed has been introduced as another alternative to external beam RT, offering sterilization of the cavity surface with steep dose gradients towards the healthy brain. This consensus paper summarizes current local treatment strategies for resectable brain metastases regarding available data and patient-centered decision-making.

Efficacy of neoadjuvant stereotactic radiotherapy in brain metastases from solid cancer: a systematic review of literature and meta-analysis

Neoadjuvant stereotactic radiotherapy (NaSRT) is a novel strategy for brain metastasis (BM) treatment, promising to achieve good local control, improved survival, and low toxicity. This is a systematic review of available literature and meta-analysis of 8 articles eligible for inclusion after searching MEDLINE via PubMed, Web-of-science, Cochrane Wiley, and Embase databases up to March 2023. A total of 484 patients undergoing NaSRT to treat 507 lesions were included. The median age was 60.9 (IQR 57-63) years, with a median tumor volume of 12.1 (IQR 9-14) cm3. The most frequent histology was non-small-cell lung cancer (41.3%), followed by breast (18.8%), and melanoma (14.3%). Lesions had a preferred supratentorial location (77.4%). Most of the studies used a single fraction schedule (91% of patients, n = 440). Treatment parameters were homogeneous and showed a median dose of 18 (IQR 15.5-20.5) Gy at a median of 80% isodose. Surgery was performed after a median of 1.5 (IQR 1-2.4) days and achieved gross-total extent in 94% of cases. Median follow-up was 12.9 (IQR 10-15.7) months. NaSRT showed an overall mortality rate of 58% (95% CI 43-73) at the last follow-up. Actuarial outcomes rates were 60% (95% CI 55-64) for 1-year overall survival (1y-OS), 38% (95% CI 33-43) for 2y-OS, 29% (95% CI 24-34) for 3y-OS; overall 15% (95% CI 11-19) for local failure, 46% (95% CI 37-55) for distant brain failure, 6% (95% CI 3-8) for radionecrosis, and 5% (95% CI 3-8) for leptomeningeal dissemination. The median local progression-free survival time was 10.4 (IQR 9.5-11.4) months, while the median survival without distant failure was 7.4 (IQR 6.9-8) months. The median OS time for the entire cohort was 17 (IQR 14.9-17.9) months. Existing data suggest that NaSRT is effective and safe in the treatment of BMs, achieving good local control on BMs with and low incidence of radionecrosis and leptomeningeal dissemination. Distant control appears limited compared to other radiation regimens.

The Management of Oligometastatic Disease in Colorectal Cancer: Present Strategies and Future Perspectives

Oligometastatic disease has been described as an intermediate clinical state between localized cancer and systemically metastasized disease. Recent clinical studies have shown prolonged survival when aggressive locoregional approaches are added to systemic therapies in patients with oligometastases. The aim of this review is to outline the newest options to treat oligometastatic colorectal cancer (CRC), also considering its molecular patterns. We present an overview of the available local treatment strategies, including surgical procedures, stereotactic body radiation therapy (SBRT), thermal ablation, as well as trans-arterial chemoembolization (TACE) and selective internal radiotherapy (SIRT). Moreover, since imaging methods provide crucial information for the early diagnosis and management of oligometastatic CRC, we discuss the role of modern radiologic techniques in selecting patients that are amenable to potentially curative locoregional treatments.

Advances in Radiotherapy for Brain Metastases

Radiotherapy remains a cornerstone treatment of brain metastases. With new treatment advances, patients with brain metastases are living longer, and finding solutions for mitigating treatment-related neurotoxicity and improving quality of life is important. Historically, whole-brain radiation therapy (WBRT) was widely used but treatment options such as hippocampal sparing WBRT and stereotactic radiosurgery (SRS) have emerged as promising alternatives. Herein, we discuss the recent advances in radiotherapy for brain metastases including the sparing of critical structures that may improve long-term neurocognitive outcomes (eg, hippocampus, fornix) that may improve long-term neurocognitive outcome, evidence supporting preoperative and fractionated-SRS, and treatment strategies for managing radiation necrosis.

Neoadjuvant Stereotactic Radiotherapy for Brain Metastases: Systematic Review and Meta-Analysis of the Literature and Ongoing Clinical Trials

Simple Summary

The available treatment strategies for patients with brain metastases remain suboptimal, with current research focused on identifying therapies intended to improve patient outcomes while reducing the risk of treatment-related complications. Several studies have investigated the role of pre-operative neoadjuvant stereotactic radiotherapy, and have proposed it as a valid alternative to post-operative adjuvant stereotactic radiotherapy. The aim of our systematic review was to comprehensively analyze the current literature and ongoing clinical trials evaluating neoadjuvant stereotactic radiotherapy in patients with brain metastases, describing treatment protocols and related outcomes. Early evidence suggests that neoadjuvant stereotactic radiotherapy may offer rates of local control and overall survival comparable to those obtained with adjuvant postoperative SRS, but comparative studies are currently lacking. In addition, neoadjuvant stereotactic radiotherapy shows low rates of post-treatment radiation necrosis and leptomeningeal metastases. Ongoing clinical trials aim to evaluate long-term outcomes in large patient cohorts, with some focused on comparing neoadjuvant stereotactic radiotherapy to adjuvant stereotactic radiosurgery.

Abstract

Background: Brain metastases (BMs) carry a high morbidity and mortality burden. Neoadjuvant stereotactic radiotherapy (NaSRT) has shown promising results. We systematically reviewed the literature on NaSRT for BMs. Methods: PubMed, EMBASE, Scopus, Web-of-Science, Cochrane, and ClinicalTrial.gov were searched following the PRISMA guidelines to include studies and ongoing trials reporting NaSRT for BMs. Indications, protocols, and outcomes were analyzed using indirect random-effect meta-analyses. Results: We included 7 studies comprising 460 patients with 483 BMs, and 13 ongoing trials. Most BMs originated from non-small lung cell carcinoma (41.4%), breast cancer (18.7%) and melanoma (43.6%). Most patients had single-BM (69.8%) located supratentorial (77.8%). Patients were eligible if they had histologically-proven primary tumors and ≤4 synchronous BMs candidate for non-urgent surgery and radiation. Patients with primary tumors clinically responsive to radiotherapy, prior brain radiation, and leptomeningeal metastases were deemed non-eligible. Median planning target volume was 9.9 cm³ (range, 2.9–57.1), and NaSRT was delivered in 1-fraction (90.9%), 5-fraction (4.8%), or 3-fraction (4.3%), with a median biological effective dose of 39.6 Gy10 (range, 35.7–60). Most patients received piecemeal (76.3%) and gross-total (94%) resection after a median of 1-day (range, 1–10) post-NaSRT. Median follow-up was 19.2-months (range, 1–41.3). Actuarial post-treatment rates were 4% (95%CI: 2–6%) for symptomatic radiation necrosis, 15% (95%CI: 12–18%) and 47% (95%CI: 42–52%) for local and distant recurrences, 6% (95%CI: 3–8%) for leptomeningeal metastases, 81% (95%CI: 75–87%) and 59% (95%CI: 54–63%) for 1-year local tumor control and overall survival. Conclusion: NaSRT is effective and safe for BMs. Ongoing trials will provide high-level evidence on long-term post-treatment outcomes, further compared to adjuvant stereotactic radiotherapy.

Treatment of breast cancer brain metastases: radiotherapy and emerging preclinical approaches

The breast is one of the common primary sites of brain metastases (BM). Radiotherapy for BM from breast cancer may include whole brain radiation therapy (WBRT), stereotactic radiosurgery (SRS), and stereotactic radiotherapy (SRT), but a consensus is difficult to reach because of the wide and varied protocols, indications, and outcomes of these interventions. Overall, dissemination of disease, patient functional status, and tumor size are all important factors in the decision of treatment with WBRT or SRS. Thus far, previous studies indicate that WBRT can improve tumor control compared to SRS, but increase side effects, however no randomized trials have compared the efficacy of these therapies in BM from breast cancer. Therapies targeting long non-coding RNAs and transcription factors, such as MALAT1, HOTAIR, lnc-BM, TGL1, and ATF3, have the potential to both prevent metastatic spread and treat BM with improved radiosensitivity. Given the propensity for HER2+ breast cancer to develop BM, the above-mentioned cell lines may represent an important target for future investigations, and the development of everolimus and pyrotinib are equally important.

Neoadjuvant fractionated stereotactic radiotherapy followed by piecemeal resection of brain metastasis: a case series of 20 patients

BACKGROUND

The safety and effectiveness of neoadjuvant fractionated stereotactic radiotherapy (FSRT) before piecemeal resection of brain metastasis (BM) remains unknown.

METHODS

We retrospectively reviewed 20 consecutive patients with BM who underwent neoadjuvant FSRT followed by piecemeal resection between July 2019 and March 2021. The prescribed dose regimens were as follows: 30 Gy (n = 11) or 35 Gy (n = 9) in five fractions.

RESULTS

The mean follow-up duration was 7.8 months (range 2.2-22.3). The median age was 67 years (range 51-79). Fourteen patients were male. All patients were symptomatic. All tumors were located in the supratentorial compartment. The median maximum diameter and volume were 3.7 cm (range 2.6-4.9) and 17.6 cm3 (range 5.6-49.7), respectively. The median time from the end of FSRT to resection was 4 days (range 1-7). Nausea (CTCAE Grade 2) occurred in one patient and simple partial seizures (Grade 2) in two patients during radiation therapy. Gross total removal was performed in seventeen patients and sub-total removal in three patients. Postoperative complications were deterioration of paresis in two patients. Local recurrence was found in one patient (5.0%) who underwent sub-total resection at 2 months after craniotomy. Distant recurrence was found in six patients (30.0%) at a median of 6.9 months. Leptomeningeal disease recurrence was found in one patient (5.0%) at 3 months. No radiation necrosis developed.

CONCLUSIONS

Neoadjuvant FSRT appears to be a safe and effective approach for patients with BM requiring piecemeal resection. A multi-institutional prospective trial is needed.

Is local radiotherapy a viable option for patients with an opening of the ventricles during surgical resection of brain metastases?

Background

Local hypofractionated stereotactic radiotherapy (HFSRT) of the resection cavity is emerging as the standard of care in the treatment of patients with a limited number of brain metastases as it warrants less neurological impairment compared to whole brain radiotherapy. In periventricular metastases surgical resection can lead to an opening of the ventricles and subsequently carries a potential risk of cerebrospinal tumour cell dissemination. The aim of this study was to assess whether local radiotherapy of the resection cavity is viable in these cases.

Methods

From our institutional database we analyzed the data of 125 consecutive patients with resected brain metastases treated in our institution with HFSRT between 2009 and 2017. The incidence of LMD, overall survival (OS), local recurrence (LC) and distant recurrence were evaluated depending on ventricular opening (VO) during surgery.

Results

From all 125 patients, the ventricles were opened during surgery in 14 cases (11.2%). None of the patients with VO and 7 patients without VO during surgery developed LMD (p = 0.371). OS (p = 0.817), LC (p = 0.524) and distant recurrence (p = 0.488) did not differ in relation to VO during surgical resection. However, the incidence of distant intraventricular recurrence was slightly increased in patients with VO (14.3% vs. 2.7%, p < 0.01).

Conclusion

VO during neurosurgical resection did not affect the outcome after HFSRT of the resection cavity in patients with brain metastases. Particularly, the incidence of LMD was not increased in patients receiving local HFSRT after VO. HFSRT can therefore be offered independently of VO as a local treatment of tumor bed after resection of brain metastases.

Outcomes of Treatment for Melanoma Brain Metastases

Background

Historically, melanoma with brain metastases has a poor prognosis. In this retrospective medical record review, we report basic clinicopathological parameters and the outcomes of patients with melanoma and brain metastases treated with different treatment modalities before the era of immunotherapy and modern radiotherapy technique.

Methods

Patients with metastatic melanoma were treated with surgery, radiotherapy, and/or systemic therapy from 1998 to 2017. In our study, they were identified and stratified depending on treatment methods. Overall survival was defined as the time from the date of brain metastases to the death or last follow-up (2019 June 1^st). Survival curves were estimated using the Kaplan–Meier method that was employed to calculate the hazard ratio.

Results

Six (12%) of 50 patients are still alive as of the last follow-up. The median overall survival from the onset of brain metastases was 11 months. The longest survival time was observed in patients treated by surgery followed by radiotherapy, surgery followed by radiotherapy and systemic therapy, and also radiotherapy followed by systemic therapy. The shortest survival was observed in the best supportive care group and patients treated by systemic therapy only.

Conclusions

Patients with brain metastases achieved better overall survival when treated by combined treatment modalities: surgery followed by radiotherapy (26.6 months overall survival), combining surgery, radiotherapy, and systemic therapy (18.7 months overall survival), and also radiotherapy followed by systemic therapy (13.8 months overall survival).

Systemic Therapies for Melanoma Brain Metastases: A Primer for Radiologists

OBJECTIVE

The purpose of this article is to provide a primer for radiologists outlining the modern systemic therapies used in melanoma brain metastases, including tyrosine kinase inhibitors and immune checkpoint inhibitors. The role of radiologic treatment response evaluation will be discussed from the standpoint of both modern systemic therapies and more traditional treatments.

CONCLUSION

Understanding the role of systemic treatments in melanoma brain metastases is critical for oncologic imaging interpretation in this unique patient population.

Cranial irradiation acutely and persistently impairs injury-induced microglial proliferation

Microglia, the resident immune cells of the central nervous system (CNS), play multiple roles in maintaining CNS homeostasis and mediating tissue repair, including proliferating in response to brain injury and disease. Cranial irradiation (CI), used for the treatment of brain tumors, has a long-lasting anti-proliferative effect on a number of cell types in the brain, including oligodendrocyte progenitor and neural progenitor cells; however, the effect of CI on CNS-resident microglial proliferation is not well characterized. Using a sterile cortical needle stab injury model in mice, we found that the ability of CNS-resident microglia to proliferate in response to injury was impaired by prior CI, in a dose-dependent manner, and was nearly abolished by a 20 ​Gy dose. Similarly, in a metastatic tumor model, prior CI (20 ​Gy) reduced microglial proliferation in response to tumor growth. The effect of irradiation was long-lasting; 20 ​Gy CI 6 months prior to stab injury significantly impaired microglial proliferation. We also investigated how stab and/or irradiation impacted levels of P2Y12R, CD68, CSF1, IL-34 and CSF1R, factors involved in the brain’s normal response to injury. P2Y12R, CD68, CSF1, and IL-34 expression were altered by stab similarly in irradiated mice and controls; however, CSF1R was differentially affected. qRT-PCR and flow cytometry analyses demonstrated that CI reduced overall Csf1r mRNA levels and microglial specific CSF1R protein expression, respectively. Interestingly, Csf1r mRNA levels increased after injury in unirradiated controls; however, Csf1r levels were persistently decreased in irradiated mice, and did not increase in response to stab. Together, our data demonstrate that CI leads to a significant and lasting impairment of microglial proliferation, possibly through a CSF1R-mediated mechanism.

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Irradiation leads to a long-term deficit in injury-induced microglial proliferation.

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Irradiation reduces microglial proliferation associated with tumor growth.

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Irradiation decreases microglial CSF1R and prevents its upregulation after injury.