Do patients receiving whole-brain radiotherapy for brain metastases from renal cell carcinoma benefit from escalation of the radiation dose?

Factors associated with the local control of brain metastases: a systematic search and machine learning application

BACKGROUND

Enhancing Local Control (LC) of brain metastases is pivotal for improving overall survival, which makes the prediction of local treatment failure a crucial aspect of treatment planning. Understanding the factors that influence LC of brain metastases is imperative for optimizing treatment strategies and subsequently extending overall survival. Machine learning algorithms may help to identify factors that predict outcomes.

METHODS

This paper systematically reviews these factors associated with LC to select candidate predictor features for a practical application of predictive modeling. A systematic literature search was conducted to identify studies in which the LC of brain metastases is assessed for adult patients. EMBASE, PubMed, Web-of-Science, and the Cochrane Database were searched up to December 24, 2020. All studies investigating the LC of brain metastases as one of the endpoints were included, regardless of primary tumor type or treatment type. We first grouped studies based on primary tumor types resulting in lung, breast, and melanoma groups. Studies that did not focus on a specific primary cancer type were grouped based on treatment types resulting in surgery, SRT, and whole-brain radiotherapy groups. For each group, significant factors associated with LC were identified and discussed. As a second project, we assessed the practical importance of selected features in predicting LC after Stereotactic Radiotherapy (SRT) with a Random Forest machine learning model. Accuracy and Area Under the Curve (AUC) of the Random Forest model, trained with the list of factors that were found to be associated with LC for the SRT treatment group, were reported.

RESULTS

The systematic literature search identified 6270 unique records. After screening titles and abstracts, 410 full texts were considered, and ultimately 159 studies were included for review. Most of the studies focused on the LC of the brain metastases for a specific primary tumor type or after a specific treatment type. Higher SRT radiation dose was found to be associated with better LC in lung cancer, breast cancer, and melanoma groups. Also, a higher dose was associated with better LC in the SRT group, while higher tumor volume was associated with worse LC in this group. The Random Forest model predicted the LC of brain metastases with an accuracy of 80% and an AUC of 0.84.

CONCLUSION

This paper thoroughly examines factors associated with LC in brain metastases and highlights the translational value of our findings for selecting variables to predict LC in a sample of patients who underwent SRT. The prediction model holds great promise for clinicians, offering a valuable tool to predict personalized treatment outcomes and foresee the impact of changes in treatment characteristics such as radiation dose.

Consensus statements on the management of metastatic renal cell carcinoma from the Hong Kong Urological Association and the Hong Kong Society of Uro-Oncology 2019

BACKGROUND

To establish a set of consensus statements for the management of metastatic renal cell carcinoma, a total of 12 urologists and clinical oncologists from two professional associations in Hong Kong formed an expert consensus panel.

METHODS

Through a series of meetings and using the modified Delphi method, the panelists presented recent evidence, discussed clinical experiences, and drafted consensus statements on several areas of focus regarding the management of metastatic renal cell carcinoma. Each statement was eventually voted upon by every panelist based on the practicability of recommendation.

RESULTS

A total of 46 consensus statements were ultimately accepted and established by panel voting.

CONCLUSIONS

Derived from recent evidence and expert insights, these consensus statements were aimed at providing practical guidance to optimize metastatic renal cell carcinoma management and promote a higher standard of clinical care.

Estimating the Lifespan of Elderly Patients With Cerebral Metastases from Kidney Cancer

BACKGROUND/AIM

Outcomes of elderly patients with cerebral metastases from kidney cancer may be improved by personalized treatment. A scoring instrument for estimating survival in these patients is presented.

PATIENTS AND METHODS

Twenty-four elderly kidney cancer patients receiving whole-brain irradiation (WBI) were retrospectively investigated. WBI-regimen and six pre-treatment factors were evaluated including age, gender, performance score, number of cerebral metastases, extracranial metastases and time from kidney cancer diagnosis to WBI.

RESULTS

Number of cerebral metastases (p=0.194) and time from kidney cancer diagnosis to WBI (p=0.107) correlated with survival and were included in the instrument. Based on these factors, patient scores of 0, 1 and 2 points resulted in 6-month survival rates of 0%, 15% and 60% (p=0.131), respectively. Two groups were designed, 0-1 and 2 points, with 6-month survival rates of 11% and 60% (p=0.108), respectively.

CONCLUSION

This new instrument can assist physicians aiming to estimate a patient's survival prognosis to provide personalized treatment.

Are hypothalamic- pituitary (HP) axis deficiencies after whole brain radiotherapy (WBRT) of relevance for adult cancer patients? - a systematic review of the literature

Background

Cranial radiotherapy (cRT) can induce hormonal deficiencies as a consequence of significant doses to the hypothalamic-pituitary (HP) axis. In contrast to profound endocrinological follow-up data from survivors of childhood cancer treated with cRT, little knowledge exists for adult cancer patients.

Methods

A systematic search of the literature was conducted using the PubMed database and the Cochrane library offering the basis for our debate of the relevance of HP axis impairment after cRT in adult cancer patients. Against the background of potential relevance for patients receiving whole brain radiotherapy (WBRT), a particular focus was set on the temporal onset of hypopituitarism and the radiation dose to the HP axis.

Results

Twenty-eight original papers with a total of 1728 patients met the inclusion criteria. Radiation doses to the HP area ranged from 4 to 97 Gray (Gy). Hypopituitarism incidences ranged from 20 to 93% for adult patients with nasopharyngeal cancer or non-pituitary brain tumors. No study focused particularly on hypopituitarism after WBRT. The onset of hypopituitarism occurred as early as within the first year following cRT (range: 3 months to 25.6 years). However, since most studies started follow-up evaluation only several years after cRT, early onset of hypopituitarism might have gone unnoticed.

Conclusion

Hypopituitarism occurs frequently after cRT in adult cancer patients. Despite the general conception that it develops only after several years, onset of endocrine sequelae can occur within the first year after cRT without a clear threshold. This finding is worth debating particularly in respect of treatment options for patients with brain metastases and favorable survival prognoses.

Radiotherapy for Brain Metastases From Renal Cell Carcinoma in the Targeted Therapy Era: The University of Rochester Experience

OBJECTIVES

Radiotherapy remains the standard approach for brain metastases from renal cell carcinoma (RCC). Kinase inhibitors (KI) have become standard of care for metastatic RCC. They also increase the radiosensitivity of various tumor types in preclinical models. Data are lacking regarding the effect of KIs among RCC patients undergoing radiotherapy for brain metastases. We report our experience of radiotherapy for brain metastatic RCC in the era of targeted therapy and analyzed effects of concurrent KI therapy.

METHODS

We retrospectively analyzed 25 consecutive patients who received radiotherapy for brain metastases from RCC with whole-brain radiotherapy (WBRT), stereotactic radiosurgery (SRS), or both. Kaplan-Meier rates of overall survival (OS) and brain progression-free survival (BPFS) were calculated and univariate analyses performed.

RESULTS

Lower diagnosis-specific graded prognostic assessment (DS-GPA) score and multiple intracranial metastases were associated with decreased OS and BPFS on univariate analysis; DS-GPA is also a prognostic factor on multivariate analysis. There was no significant difference in OS or BPFS for SRS compared with WBRT or WBRT and SRS combined. The concurrent use of KI was not associated with any change in OS or BPFS.

CONCLUSIONS

This hypothesis-generating analysis suggests among patients with brain metastatic RCC treated with the most current therapies, those selected to undergo SRS did not experience significantly different survival or control outcomes than those selected to undergo WBRT. From our experience to date, limited in patient numbers, there seems to be neither harm nor benefit in using concurrent KI therapy during radiotherapy. Given that most patients progress systemically, we would recommend considering KI use during brain radiotherapy in these patients.

Stereotactic body radiotherapy for renal cell cancer and pancreatic cancer : Literature review and practice recommendations of the DEGRO Working Group on Stereotactic Radiotherapy

PURPOSE

This report of the Working Group on Stereotactic Radiotherapy of the German Society of Radiation Oncology (DEGRO) aims to provide a literature review and practice recommendations for stereotactic body radiotherapy (SBRT) of primary renal cell cancer and primary pancreatic cancer.

METHODS

A literature search on SBRT for both renal cancer and pancreatic cancer was performed with focus on prospective trials and technical aspects for clinical implementation.

RESULTS

Data on renal and pancreatic SBRT are limited, but show promising rates of local control for both treatment sites. For pancreatic cancer, fractionated SBRT should be preferred to single-dose treatment to reduce the risk of gastrointestinal toxicity. Motion-compensation strategies and image guidance are paramount for safe SBRT delivery in both tumor entities.

CONCLUSION

SBRT for renal cancer and pancreatic cancer have been successfully evaluated in phase I and phase II trials. Pancreatic SBRT should be practiced carefully and only within prospective protocols due to the risk of severe gastrointestinal toxicity. SBRT for primary renal cell cancer appears a viable option for medically inoperable patients but future research needs to better define patient selection criteria and the detailed practice of SBRT.

Stereotactic Radiosurgery for Renal Cancer Brain Metastasis: Prognostic Factors and the Role of Whole-Brain Radiation and Surgical Resection

Background. Renal cell carcinoma is a frequent source of brain metastasis. We present our consecutive series of patients treated with Stereotactic Radiosurgery (SRS) and analyse prognostic factors and the interplay of WBRT and surgical resection. Methods. This is a retrospective study of 66 patients with 207 lesions treated with the Cyberknife radiosurgery system in our institution. The patients were followed up with imaging and clinical examination 1 month and 2-3 months thereafter for the brain metastasis. Patient, treatment, and outcomes characteristics were analysed. Results. 51 male (77.3%) and 15 female (22.7%) patients, with a mean age of 58.9 years (range of 31–85 years) and a median Karnofsky Performance Status (KPS) of 90 (range of 60–100), were included in the study. The overall survival was 13.9 months, 21.9 months, and 5.9 months for the patients treated with SRS only, additional surgery, and WBRT, respectively. The actuarial 1-year Local Control rates were 84%, 94%, and 88% for SRS only, for surgery and SRS, and for WBRT and additional SRS, respectively. Conclusions. Stereotactic radiosurgery is a safe and effective treatment option in patients with brain metastases from RCC. In case of a limited number of brain metastases, surgery and SRS might be appropriate.

[The role of whole brain radiation therapy for brain metastases]

Brain metastases are the leading cause of intracranial malignancy and a major cause of mortality and morbidity. From 20 to 40% of cancer patients develop brain metastases. The irradiation of the whole brain remains the most commonly undertaken treatment, but should be discussed in relation to other therapeutic alternatives such as stereotactic radiotherapy or the use of new chemotherapy drugs. Its use according to pathology should be discussed. It can lead to a long-term neurocognitive toxicity that should be evaluated more precisely. This literature review aims to highlight the role of whole-brain radiotherapy used alone or in combination with other treatments.

Management of brain metastasis: past lessons, modern management, and future considerations

Brain metastasis is a major challenge for patients, physicians, and the broader health care system, with approximately 170,000 new cases per year. After a diagnosis of brain metastasis, patients have a poor prognosis, but modern management has made significant advances in the past two decades to improve palliative efficacy and patient survival through a multidisciplinary approach. A number of factors must be taken into consideration in the treatment approach, including the number of intracranial lesions, the control of extracranial disease, and the patient's overall health, while weighing the benefits of treatment against the toxicities, both acute and chronic. With quality of life as an emphasis, emerging concepts for modern management of brain metastasis have sought to minimize long-term toxicities. The economic impact of such strategies for patients and the health care system has been demonstrated in some studies, but has not been a consistent area of focus. Each of these strategies, as well as novel therapeutics, has embraced the concept of personalized treatment. This review will discuss the current knowledge of modern multidisciplinary management of brain metastasis and look forward to emerging concepts.

Dose-escalation of whole-brain radiotherapy for brain metastasis in patients with a favorable survival prognosis

BACKGROUND

Patients with brain metastases who have a favorable survival prognosis may benefit from intensive treatments, including neurosurgery and radiosurgery. However, many patients cannot receive such treatments, and whole-brain radiotherapy (WBRT) alone is their only option. The most common WBRT schedule is 30 grays (Gy) in 10 fractions. In this retrospective study, the authors investigated whether these patients benefit from a dose escalation beyond 30 Gy.

METHODS

Data from 109 patients who received 30 Gy in 10 fractions were compared with 75 patients who received 40 Gy in 20 fractions. All patients had a favorable survival prognosis. Both groups were compared for local control (LC) and overall survival (OS). Subgroup analyses were performed for patients who had less radiosensitive tumors (N = 27) and for other patients (N = 157).

RESULTS

The LC rate at 1 year was 28% after 30 Gy and 44% after 40 Gy (P = .064). On multivariate analysis, the 40 Gy dose was associated with improved LC (P = .047). The survival rate at 1 year was 50% after 30 Gy and 61% after 40 Gy (P = .007). On multivariate analysis, the 40 Gy dose was associated with improved OS (P = .008). On subgroup analysis of patients who had less radiosensitive tumors, the 1-year LC rate was 7% after 30 Gy and 38% after 40 Gy (P = .031); and the 1-year OS rate was 40% and 73%, respectively (P = .008). On subgroup analysis of patients who had other tumor types, the 1-year LC rate was 31% after 30 Gy and 45% after 40 Gy (P = .26); and the 1-year OS rate was 52% and 59%, respectively (P = .08).

CONCLUSIONS

Escalation of the WBRT dose beyond 30 Gy resulted in better outcomes, particularly for patients who had less radiosensitive tumors.

Brain metastases from renal cell carcinoma. Should we change the current standard?

Renal cell carcinoma (RCC) is one of the most common sources of brain metastases, with an incidence that varies widely from 4% to 48% according to different studies. In addition, asymptomatic metastases occur in up to 33% of patients with metastatic RCC, further complicating the decision-making process in this poor prognosis population. The purpose of this review is to cover in depth the present state of knowledge on the diagnosis and management of patients with brain metastases from RCC, in order to assess whether the current standard should be challenged. The existing systems to predict response and survival will be reviewed, as well as the available therapeutic options regarding local treatment and systemic therapy, all within the context of updated data from clinical trials. In this regard, the role of novel targeted agents for the treatment of brain metastases from RCC, such as the multi-targeted receptor tyrosine kinase inhibitors sunitinib and sorafenib, will be updated and discussed.