Dose/effect relationships for brain metastases

[Repeated irradiation of brain metastases under stereotactic conditions: A review of the literature]

Stereotactic radiotherapy has become a standard in the management of patients with brain metastases; its main interest is to differ whole brain radiotherapy, provider of neurocognitive toxicity and to increase the rate of local control. The repetition of radiotherapy sessions under stereotactic conditions is not codified, neither on the number of technically and clinically possible sessions, nor on the maximum total number or volume of metastases to be treated. The purpose of this review is to analyse the data in the literature concerning repeated irradiations under stereotactic conditions. The second reirradiation in stereotactic condition shows satisfactory results in terms of overall survival, local control, and toxicity. However, we lack data for patients receiving more than two sessions of SRS as well as to define dose constraints to reirradiated healthy tissues. Prospective trials are still needed to validate the management of recurrent brain metastases after initial SRS.

Management of patients with brain metastases from non-small cell lung cancer and adverse prognostic features: multi-national radiation treatment recommendations are heterogeneous

Background

Different management options exist for patients with brain metastases from non-small cell lung cancer (NSCLC), patients whose treatment with whole brain radiotherapy (WBRT) has become more controversial over the last decade. It is not trivial to find the optimal balance of over- versus undertreatment in these patients. Several recent trials, including the randomized QUARTZ trial now influence the decision to recommend or withhold WBRT for patients with unfavorable prognosis, and similarly, for favorable prognosis patients, the balance between radiosurgery alone or WBRT has become a nuanced decision. Additionally, the availability of intracranially active targeted agent for some subsets of these patients has added another layer of complexity to the decision-making.

Methods

A multinational consortium of expert radiation oncologists was established with the aim of compiling treatment recommendations for challenging scenarios, in this case the choice between optimal supportive care (SC), WBRT and other types of radiation therapy (RT). We distributed 17 cases to 7 radiation oncologists who were allowed to involve coworkers to provide their treatment recommendations. The cases differed in extra- and intracranial disease extent, histology, age and other prognostic factors. Expert recommendations were tabulated with the aim of providing guidance.

Results

Regarding willingness to include the 17 patients in the QUARTZ trial, the rates of trial inclusion were low (range 0/7 to 3/7). Experts not recommending trial inclusion provided their treatment recommendations. These suggestions differed widely for most of the patients. It was not uncommon to see 3 or 4 different recommendations. In general, few (0–2) recommended SC. Some kind of local treatment was suggested by the majority of experts for all 17 patients. Commonly, stereotactic single-fraction radiosurgery (SRS) or stereotactic fractionated radiotherapy (SFRT) were recommended by many experts, also for patients with 5–7 lesions. The highest proportion of recommendations towards WBRT in any patient was 3/7. It was also quite common for patients with multiple metastases of varying size that experts suggested combinations of resection, post-operative SRS/SFRT and SRS/SFRT to intact lesions. Despite recommending active treatment, experts were often willing to include the patients in a hypothetical protocol investigating radiotherapy utilization in the last 30 days of life (assessment of factors predicting early death).

Conclusions

WBRT was infrequently recommended. Even in patients with adverse prognostic features that raised the experts’ awareness of an increased risk for futile treatment near the end of life, SRS/SFRT were more often recommended than optimal supportive care, unless a patient decided to forego active treatment.

Electronic supplementary material

The online version of this article (10.1186/s13014-019-1237-9) contains supplementary material, which is available to authorized users.

The challenge of durable brain control in patients with brain-only metastases from breast cancer

The vast majority of patients with brain metastases from breast cancer have extracranial metastases, e.g., in the liver, lungs or bones, with serious impact on prognosis. Limited research has been performed on patients with brain-only disease. We analyzed patterns of treatment, brain control and survival in uni- and multivariate analyses. All 25 patients with brain-only disease were treated with radiotherapy (whole-brain radiotherapy (WBRT) with or without stereotactic radiotherapy/radiosurgery (SRS) or surgical resection) and most patients with systemic treatment later during the disease trajectory. Only a minority of patients remained free from brain progression at 1 year after their initial therapy, regardless of initial treatment approach (median brain progression-free survival 6.2 months). However, overall survival was significantly better after initial surgical resection/SRS as compared to upfront WBRT (median 24.1 and 5.2 months, respectively). For all patients combined, median survival was 11.7 months (2-year survival rate 28 %). Several prognostic factors for shorter survival were identified in multivariate regression analysis: lower KPS, triple-negative tumor, coordination deficit, older age, lack of upfront surgical resection or SRS, and lack of endocrine or HER2-directed therapy after brain metastases treatment. Although durable brain control and long-term survival beyond 5 years could be achieved in a subset of patients (largely after successful salvage), progression of brain metastases during the first year after diagnosis was common. Prognosis was influenced by patient-, disease- and treatment-related factors.

Treatment of brain metastasis from lung cancer

Brain metastases are not only the most common intracranial neoplasm in adults but also very prevalent in patients with lung cancer. Patients have been grouped into different classes based on the presence of prognostic factors such as control of the primary tumor, functional performance status, age, and number of brain metastases. Patients with good prognosis may benefit from more aggressive treatment because of the potential for prolonged survival for some of them. In this review, we will comprehensively discuss the therapeutic options for treating brain metastases, which arise mostly from a lung cancer primary. In particular, we will focus on the patient selection for combined modality treatment of brain metastases, such as surgical resection or stereotactic radiosurgery (SRS) combined with whole brain irradiation; the use of radiosensitizers; and the neurocognitive deficits after whole brain irradiation with or without SRS. The benefit of prophylactic cranial irradiation (PCI) and its potentially associated neuro-toxicity for both small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) are also discussed, along with the combined treatment of intrathoracic primary disease and solitary brain metastasis. The roles of SRS to the surgical bed, fractionated stereotactic radiotherapy, WBRT with an integrated boost to the gross brain metastases, as well as combining WBRT with epidermal growth factor receptor (EGFR) inhibitors, are explored as well.

Presentation and outcome in cancer patients with extensive spread to the brain

BACKGROUND

Controversy exists around the preferred management of patients with brain metastases and limited survival expectation, e.g. because of extensive brain involvement. Few studies have focused on this particular group of patients.

FINDINGS

A group of 24 patients with a large number of brain metastases, defined as 10 or more on computed tomography scans, who were managed with palliative whole-brain radiotherapy (WBRT), typically 30 Gy in 10 fractions, were analyzed. The median number of lesions was 14. The patient characteristics were comparable to those of studies in the general population with brain metastases, except for the fact that all patients had active sites of extracranial disease. Clinical benefit, imaging response and overall survival were lower than expected. Median survival, for example was 2 months. Trends towards better survival were found in patients with brain metastases detected at first cancer diagnosis (synchronous manifestation, treatment naïve) and those with better prognostic features according to the graded prognostic assessment (GPA) score.

CONCLUSIONS

The benefit of WBRT did not meet the expectations, suggesting that consideration should be given to best supportive care including corticosteroid administration, especially if a patient belongs to the lowest GPA class.

Use of palliative radiotherapy trials for clinical biomarker development

INTRODUCTION

Approximately one quarter of all cancer patients will require palliative radiation treatment at some point during the course of their disease, but only a minority of these patients are entered in clinical trials.

ETHICAL ASSESSMENT OF BIOMARKERS IN PALLIATIVE RADIOTHERAPY TRIALS

We review the literature debating the ethics of inclusion of "palliative" patients on clinical trials. We suggest that these patients provide a potentially valuable resource that can be leveraged to facilitate the discovery and validation of biomarkers predictive of radiation response and toxicity. In addition, this patient population offers valuable opportunities to test combination of radiation and targeted therapies to screen for activity, toxicity and biomarkers in a relatively safe manner.

CONCLUSION

Patients undergoing palliative radiation therapy may provide new opportunities for the development and testing of predictive radiotherapy biomarkers as well as affording opportunities to test combinations of radiation and targeted therapies.

Chemotherapy and targeted molecular therapies for brain metastases

As therapy for systemic cancers improves, an increasing number of patients are developing brain metastases. Although conventional therapy with surgery, radiation therapy and radiosurgery has improved the outcome of a significant number of patients, many develop multiple lesions that are not amenable to standard treatments. In this review, the current role of chemotherapy and targeted molecular agents for brain metastases is summarized and future directions are discussed.

Whole-brain radiotherapy with or without efaproxiral for the treatment of brain metastases: Determinants of response and its prognostic value for subsequent survival

PURPOSE

To determine the prognostic factors for radiographic response and its prognostic value for subsequent survival in patients undergoing whole-brain radiotherapy (WBRT) for brain metastases.

METHODS AND MATERIALS

Five hundred fifteen eligible patients were randomized in a phase III trial evaluating WBRT and supplemental oxygen with or without efaproxiral, an allosteric modifier of hemoglobin that reduces hemoglobin oxygen-binding affinity and enhances tumor oxygenation, potentially increasing tumor radiosensitivity. Brain images were obtained at baseline and at scheduled follow-up visits after WBRT. Landmark analysis was used to assess the ability of response at selected time points to predict subsequent survival. Logistic regression was used to assess determinants of response at 3 months.

RESULTS

Treatment arm, Karnofsky Performance Status, presence or absence of liver metastases, and primary site were all determinants of response at the 3-month follow-up visit, with patients in the efaproxiral arm experiencing a 67% greater odds of response at this visit (p = 0.02). Response at 3 and 6 months was a significant prognostic factor for longer subsequent survival.

CONCLUSIONS

The 3-month scan is a valuable prognostic factor for subsequent survival in patients with brain metastases treated with WBRT. Patients in the efaproxiral arm had a higher response rate at 3 and 6 months than those in the control arm.

Short-term changes in prostacyclin secretory profile of irradiated rat cervical spinal cord

Prostaglandins changes in radiation myelopathy (RM) have been previously reported. In the present study, we decided to determine the profile of Prostacyclin (PGI2) content in irradiated rat cervical cord. Wistar rats were irradiated with doses of 2,4,6,15,25 and 30 Gy of X-rays. After 24 h, 2 and 13 weeks post-irradiation, samples of spinal cord were prepared for evaluation of PGI2 and histopathologic changes. Prostacyclin content was determined by quantification of 6-keto-prostaglandin-F1alpha (prostacyclin major metabolite). Irradiated segments of spinal cord were stained routinely for histological studies. Results of irradiated were compared to control groups. Average ratio values of 6-keto-PG-F1alpha for doses of 2-30 Gy were between 67.5% and 107%, 65.41% and 100.54%, and 62.20% and 98.89% for 24 h, 2 and 13 weeks post-irradiation, respectively. Histopathological studies showed marked gliosis and vascularities in irradiated specimens. PGI2 bimodal secretory profile was observed along with histopathological changes in this study. Our results can further emphasize on the role of PGI2 in RM.

Treatment of brain metastases from non-small-cell lung cancer (NSCLC): radiotherapy

Brain metastases occur frequently in lung-cancer patients and are associated with a crucial decrease in prognosis and impairment of Life quality. With improved treatment and earlier diagnosis of primary tumour as well as earlier detection of lesions due to improved neuroradiological diagnosis the incidence is apparently increasing. Whole-brain radiation therapy (WBRT) prolongs median survival from 1 to 3-6 months. One-year survival rate after WBRT is approximately 10-20%. Neurological function could be improved with minimal morbidity. However, long-term survival is observed in patients with favourable prognostic factors like controlled primary tumour site, no extracranial disease, good performance status and age <60 years. In these patients individually optimised aggressive treatment strategies are clearly justified. Surgical resection or radiosurgery (RS) combined with adjuvant WBRT prolong survival to approximately 8-11 months. Surgical resection is preferred when rapid relief of increased intracranial pressure is required. The incidence of new brain metastases is low in patients with poor prognostic factors. Palliative RS could be used in these patients to rapidly improve neurological deficits. In locally advanced NSCLC radiosurgery may be used to effectively control brain disease without delay in treatment of the primary tumour site. The role of prophylactic ("elective") cranial irradiation in NSCLC patients as well as the role of combined radiochemotherapy for brain metastases has to be addressed in further clinical trials in the future.

Radiosurgery and radiotherapy for non-small-cell lung cancer metastatic to brain

Non-small-cell lung cancer metastatic to brain represents a common problem in oncology. Treatment modalities include stereotactic radiosurgery (SRS), whole-brain radiotherapy (WBRT), surgical resection, supportive care, or a combination of these options. This review outlines therapeutic strategies for treatment with particular attention to the use of SRS. Radiosurgical technique, radiobiology, dose prescription, patient selection, and results of therapy are discussed. The term SRS describes a radiation procedure that utilizes a three-dimensional stereotactic localization system to precisely treat small intracranial targets with a single, large, highly focal radiation dose. Stereotactic radiosurgery is appealing for several reasons; it is minimally invasive, easily tolerated, and highly effective, and patients return to normal baseline function within 24 hours. Stereotactic radiosurgery provides much higher control rates of treated lesions than does WBRT. Randomized trials are underway to ascertain the optimal role and timing of SRS in relation to WBRT in order to maximize control, survival, quality of life, and neuropsychological outcome.

Adjuvant treatment of brain metastases

With an incidence of 15/10(5) in the general population, brain metastases constitute a serious, debilitating complication in cancer patients. The majority of those patients suffer from more than one metastasis, but up to 30% to 40% present with a solitary lesion. Whole-brain radiotherapy (WBRT) extends median survival from 1 to 2 months for treatment with steroids only, to 4 to 6 months in most series. However, long-term survival (>1-2 years) is observed in up to 10% of patients with favorable prognostic factors, such as solitary lesions, good Karnofsky performance status, and absence of extracranial disease. For those patients, individually optimized treatment is worthwhile. For good-prognosis patients with controlled extracranial disease, surgery in combination with postoperative WBRT should be considered, especially when fast relief of symptoms is mandated. For surgically inaccessible solitary lesions below a size threshold of approximately 30 ccm, stereotactic radiosurgery (RS), although never compared to surgery in a randomized fashion, seems to yield comparable results and is the treatment of choice for more than one lesion in appropriately selected patients. Nevertheless, a number of questions concerning the optimal treatment regimens for brain metastases remain. These mainly concern the radiation dose, need for a combination of RS and WBRT, relative timing of different treatment modalities, and maximum number of brain metastases that can reasonably be treated with RS when long-term progression-free survival is the goal. However, RS is definitely an excellent option for salvage and palliation in patients with short life expectancy, as it is simultaneously noninvasive and cost-effective, with short hospitalization times.

Prognostic factors in brain metastases: should patients be selected for aggressive treatment according to recursive partitioning analysis (RPA) classes?

PURPOSE

To determine whether or not Radiation Therapy Oncology Group (RTOG) recursive partitioning analysis (RPA) derived prognostic classes for patients with brain metastases are generally applicable and can be recommended as rational strategy for patient selection for future clinical trials. Inclusion of time to non-CNS death as additional endpoint besides death from any cause might result in further valuable information, as survival limitation due to uncontrolled extracranial disease can be explored.

METHODS

We performed a retrospective analysis of prognostic factors for survival and time to non-CNS death in 528 patients treated at a single institution with radiotherapy or surgery plus radiotherapy for brain metastases. For this purpose, patients were divided into groups with Karnofsky performance status (KPS) <70% and KPS > or =70%, as proposed by the RTOG.

RESULTS

Median overall survival was 2.9 months (2.0 months for patients with KPS <70% and 3.6 months for patients with KPS > or =70%, p < 0.001). We did not find other variables splitting patients with KPS <70% in different prognostic groups. However, advanced age, multiple brain metastases, presence of extracranial metastases, and uncontrolled primary tumor each predicted shorter survival in patients with KPS > or =70%. When grouped into the original RTOG RPA classes, our data set split into three subgroups with different prognosis and median survival times of 10.5, 3.5, and 2 months, respectively (p < 0.05). Only 3% of patients fell into the most favorable group. Median time to non-CNS death was 4.1 months (12.9 months in RPA class I, 4.9 months in RPA class II, and 3.8 months in RPA class III, respectively, p > 0.05 for RPA class II versus III). However, it was 8.5 months in RPA class II patients with controlled primary tumor, which was found to be the only prognostic factor for time to non-CNS death in patients with KPS > or =70%. In patients with KPS <70%, no statistically significant prognostic factors were identified for this endpoint.

CONCLUSIONS

Despite some differences, this analysis essentially confirmed the value of RPA-derived prognostic classes, as published by the RTOG, when survival was chosen as endpoint. RPA class I patients seem to be most likely to profit from aggressive treatment strategies and should be included in appropriate clinical trials. However, their number appears to be very limited. Considering time to non-CNS death, our results suggest that certain patients in RPA class II also might benefit from increased local control of brain metastases.