Selecting the Appropriate Radiation Therapy Technique for Extensive Brain Metastases from Tens to Hundreds: Should the Latest Technique Always Be the Best Option?

Brain metastases (BMs) are one of the most common metastatic lesions in adult cancer patients and the most common intracranial neoplasms in adult patients. Especially for multiple BMs, historically, whole-brain radiotherapy (WBRT) has been performed as the mainstay of therapy, which improves neurological symptoms and median survival. However, WBRT could negatively impact the patient's quality of life due to late complications. Owing to these complications, attempts have been made to use the latest radiotherapy (LRT) such as stereotactic radiosurgery (SRS) and intensity-modulated radiotherapy (IMRT) to treat BMs. However, for the extensive BMs (ranging from tens to hundreds), there are currently no prospective studies comparing WBRT with LRT such as IMRT or SRS. For extensive brain metastases, LRT cannot be the best option. Instead, upfront WBRT should be considered given its advantages and disadvantages, rather than LRT. We hope that faster and more reliable LRT for extensive BMs will be applicable for clinical practice without any clinical concerns in the near future.

Neurotoxicity from Old and New Radiation Treatments for Brain Tumors

Research regarding the mechanisms of brain damage following radiation treatments for brain tumors has increased over the years, thus providing a deeper insight into the pathobiological mechanisms and suggesting new approaches to minimize this damage. This review has discussed the different factors that are known to influence the risk of damage to the brain (mainly cognitive disturbances) from radiation. These include patient and tumor characteristics, the use of whole-brain radiotherapy versus particle therapy (protons, carbon ions), and stereotactic radiotherapy in various modalities. Additionally, biological mechanisms behind neuroprotection have been elucidated.

Pyrotinib combining with radiotherapy on breast cancer with brain metastasis

With the extensive application of anti-human epidermal growth factor receptor-2 (HER2) targeted therapy, the prognosis of HER2-positive breast cancer brain metastasis (BCBM) has been improved greatly. Due to the lack of prospective randomized controlled studies; however, the treatment of active brain metastasis (BM) remains a difficulty in clinic. Based upon the retrospective studies, an effective approach of radiotherapy combined with pyrotinib in HER2-positive BCBM treatment was investigated in present research. In all, 29 patients who had active BM in HER2-positive breast cancer (BC) and underwent whole-brain radiotherapy (WBRT) combined with pyrotinib from January 2019 to May 2021 were enrolled. The progression-free survival (PFS), overall survival (OS), clinical benefit rate (CBR), objective response rate (ORR), and drug-related adverse events (AEs) were analyzed among patients undergoing WBRT combined with concurrent or sequence pyrotinib + capecitabine. After the systematic treatments using WBRT combined with pyrotinib + capecitabine, the mPFS and mOS of BM patients were 6.5 months and 15.5 months, respectively. PFS (7.2 vs 6.2 months, p = 0.038) and OS (19.0 vs 14.0 months, p = 0.014) were longer after sequence treatments than those after concurrent treatment. The central nervous system (CNS) ORR of sequence treatment was superior to that of concurrent treatment (80.4% vs 58.6%, p < 0.05). Vomiting (17.2%) and diarrhea (10.3%) were the most common adverse reactions ⩾ grade 3. WBRT combined with pyrotinib is safe and effective for the treatments of active BM in HER2-positive BC. WBRT combined with sequence pyrotinib + capecitabine is more effective and less toxic than concurrent treatment. Therefore, sequence treatment is potentially a preferred regimen for patients with active BM in HER2-positive BC. The size and number of BM lesions, presence or absence of hepatic metastasis, and combination mode of radiotherapy and targeted therapy are independent risk factors for active BM prognosis.

Survival and prognostic factors in patients undergoing the resection of solitary brain metastasis from non-small cell lung cancer: a retrospective cohort study

BACKGROUND

Neurosurgery is the standard of care for resectable solitary brain metastasis (BM) from non-small cell lung cancer (NSCLC), but still with a poor outcome. Postoperative whole-brain radiotherapy (WBRT) was reported to reduce local recurrence, whether it could prolong survival was uncertain. In this study, we attempted to evaluate WBRT and other prognostic for overall survival (OS) in these patients.

METHODS

In this retrospective study, NSCLC patients with a solitary BM and controlled primary tumor who underwent neurosurgical resection were selected from the medical records database between January 2014 and December 2018. Clinical data, disease control/progression results and survival outcomes were obtained from the medical records, regular outpatient follow-up and telephone interviews. Univariable and multivariable Cox analyses of potential prognostic factors including patients' characteristics, BM features, tissue-based parameters and postoperative treatments were conducted. OS was illustrated using Kaplan-Meier curves, and group differences were assessed using the log-rank test. The subgroup analysis compared each variable between the WBRT group and the untreated control by the hazard ratio and its 95% confidence interval (CI).

RESULTS

A total of 94 patients were included, with a median OS of 812 days. Univariable analysis showed that postoperative WBRT and targeted therapy were associated with OS. Multivariable analysis demonstrated that postoperative WBRT [P<0.001, hazard ratio (HR) 0.357], chemotherapy (P=0.008, HR 0.512), targeted therapy (P<0.001, HR 0.265), and smaller tumor size (P=0.018, HR 0.553) were independent prognostic factors for prolonged OS. However, tissue-based parameters (Ki67 tumor cell proliferation index, epidermal growth factor receptor, and checkpoint levels) were identified as statistically insignificant factors. In the subgroup analysis, the beneficial effect of WBRT was only observed in patients that did not receive systematic treatments.

CONCLUSIONS

Postoperative WBRT and systematic treatments after solitary BM resection improve the prognosis of NSCLC patients with a controlled primary tumor. Postoperative WBRT could be considered, especially for those who not receive systematic chemotherapy or targeted therapy treatments, as they might be more likely to benefit from it.

Radiotherapy for brain metastases from small-cell lung cancer in distinct clinical indications and scenarios

Management of brain metastases (BM) from small-cell lung cancer (SCLC) is complex and not supported by a strong evidence from prospective clinical trials. Owing to the different clinical and pathological characteristics of SCLC, patients with this histology were not included in the prospective studies on the value of whole-brain radiotherapy (WBRT) and local surgical or ablative radiation treatment like stereotactic radiosurgery (SRS). Chemotherapy also represents a major part of the armamentarium against BM from SCLC due to the well-recognized chemoresponsiveness of this cancer and the frequent presentation of BM with extracranial progression. WBRT in combination with chemotherapy has long been a standard approach in this setting. However, data on the neurocognitive toxicity and the lack of documented impact on overall survival of WBRT in the management of BM from other solid tumors, as well as the increasing availability of the stereotactic radiotherapy technologies, has led to the increasing use of SRS with omission of WBRT also in SCLC. In the current review the use of different modalities of radiotherapy and ways of combining radiotherapy with chemotherapy for BM from SCLC will be presented for distinct clinical situations: presentation of BM synchronous with primary, metachronous presentation of BM—without previous prophylactic cranial irradiation (PCI) vs. after PCI, and asymptomatic BM found at the staging before PCI.

Bevacizumab as a treatment for radiation necrosis following stereotactic radiosurgery for brain metastases: clinical and radiation dosimetric impacts

BACKGROUND

Brain necrosis (RN) is a common radiotherapy sequela for brain metastases. Bevacizumab is identified as a therapeutic strategy for RN. This study aimed to study the clinical and radiobiological impacts on the efficacy of Bevacizumab in treating RN following stereotactic radiosurgery (SRS) for brain metastases.

METHODS

From April 2011 to November 2019, 40 patients diagnosed with RN after SRS for brain metastases were retrospectively analyzed. Patients were treated with Bevacizumab for RN and follow-up for 6 months using MR imaging at different timepoints. Linear regression was performed to evaluate the relationship between these variables.

RESULTS

The median time course from the end of radiotherapy to the onset of RN was 11 months (range, 7-35 months). No significant difference was found in the edema volume between the chemotherapy group and non-chemotherapy group (P>0.05). Patients received with SRS + WBRT exhibited relatively larger edema volumes post radiotherapy than those without WBRT (P<0.05). Interestingly, the ratio of BED/GTV (Gy/cm3 ) correlated positively with the severity (time for half-reduction dose of corticosteroids) (r2 =0.13, P<0.05), and negatively with the latency period (time course for development of radiation-induced brain necrosis) (r2 =0.21, P<0.01). A new radiation doses volume index, BED × GTV (Gy·cm3 ), was proposed to facilitate the risk stratifications of patients for radiation-induced brain necrosis. Furthermore, no significant difference was found in alleviating brain edema between different regimens of Bevacizumab, i.e., 5 vs. 10 mg/kg, 2 vs. >2 cycles (both P>0.05).

CONCLUSIONS

Bevacizumab is a feasible and favorable salvage treatment of BN after SRS for patients with BM. The efficacy is mainly manifested in radiological improvement and symptoms alleviation. The development of RN was found to be largely associated with radiation dose and gross tumor volume, and thus we proposed two new indexes, i.e., BED/GTV (Gy/cm3 ) for quantitative assessment of the severity and latency time, and BED × GTV (Gy·cm3 ) for risk stratifications for BN. A low dose with two cycles of Bevacizumab is recommended.

Radiotherapy to the brain: what are the consequences of this age-old treatment?

Radiotherapy (RT) has been widely used in the management of benign and malignant brain tumors for decades. However, complications can develop as a result of adjacent structures being exposed to radiation. As such, careful selection of patients and deciding on the most suitable modality of RT are crucial to minimize complications. In general, complications can be subdivided based on its timeline of onset; acute (few days to weeks), early delayed (1-6 months) and late (>6 months). Late complications such as cognitive decline and radiation necrosis can be debilitating and negatively impacts quality-of-life. New strategies to reduce RT-related complications such as with hippocampal sparing-WBRT, memantine, and focal RT (e.g., stereotactic radiosurgery) have had promising results and are being adopted in clinical practice. This review will focus on RT-related complications in the brain, with a focus on WBRT or SRS-related late adverse events, as well as measures to mitigate these complications.