Use Of Stereotactic Radiotherapy Research Articles

High barriers to treatment are associated with stereotactic radiation instead of surgery for patients with operable stage I non-small cell lung cancer†.

Although surgery is considered the standard of care for early-stage lung cancer, there has been increased use of stereotactic radiotherapy for operable patients in recent years. Given that this modality may be perceived as a more practical treatment, we hypothesized that it might be more often delivered to patients who experience barriers to care. The National Cancer Database (2018-2020) was queried for patients with clinical stage IA non-small cell lung cancer treated with surgery or stereotactic radiotherapy (48-60 Gy, 3-5 fractions), excluding patients with contraindications to surgery. Patients who had all the following characteristics were categorized as experiencing 'high barriers' to treatment: income below median national levels, lack of private insurance, treatment at a community facility and residence in non-metropolitan areas. Using multivariable logistic regression, the association between high barriers to treatment and stereotactic radiotherapy use was estimated. A total of 60829 patients were included, of whom 3382 (5.6%) experienced high barriers to treatment. Among them, 13535 (22.3%) underwent stereotactic radiotherapy and 47294 (77.7%) underwent surgery. Overall, more patients undergoing stereotactic radiotherapy faced high barriers to treatment compared to those who received surgery (8.6% vs 4.7%, P < 0.001). Geographic region was associated with the delivery of stereotactic radiotherapy (P < 0.001). The magnitude of such association was stronger among those who faced high barriers. In multivariable analysis, experiencing high barriers to treatment remained associated with receiving stereotactic radiotherapy (OR: 1.46, 95% CI 1.35-1.58). The use of stereotactic radiotherapy is more prevalent among patients facing barriers to care. Further research is needed to clarify the role of this treatment modality in early-stage lung cancer.

Acromegalia em felinos

Acromegaly in felines occurs mainly due to a pituitary adenoma of somatotropic cells, and presents slow and progressive evolution, responsible for increasing the production and secretion of growth hormones (GH). This condition is common in senile or adult male domestic cats, neutered and with short hair. The pathophysiology is due to the excessive release of GH in the adenohypophysis region, whose synthesis is regulated by growth hormone-releasing hormone (GHRH) and somatostatin, responsible for stimulating or inhibiting the secretory axis, respectively. The anabolic action of GH is responsible for increasing the secretion of IGF-1, which is mainly responsible for the clinical signs of acromegaly, such as body growth and organomegaly. The catabolic effect refers to insulin resistance. Clinical signs may be associated with secondary diabetes mellitus (DM), weight gain, exacerbated growth of various tissues and neurological signs as the tumor mass grows. The diagnosis of the disease can be performed through laboratory, imaging and endocrine tests such as the specific immunoassay for GH and/or insulin-like growth factor 1 (IGF-1). Treatment is based on controlling the DM that develops secondary to it, as well as on attempts to reduce or even inhibit the excess release of GH. Treatment can be performed with somatostatin analogues and dopamine agonists. The use of stereotactic radiotherapy can also be recommended, with favorable results for tumor reduction, as well as the surgical technique of transsphenoidal hypophysectomy, which presents better results than other techniques but is a complex surgical procedure. This project aims to inform veterinarians of this endocrine disease and its main currently recognized diagnoses and treatments, emphasizing the need to establish a differential diagnosis for difficult-to-control DM.

Whole-brain Radiotherapy With or Without a Simultaneous Integrated Boost for Treatment of Brain Metastases.

Many patients with brain metastases receive whole-brain radiotherapy (WBRT), despite the increasing use of stereotactic radiotherapy alone. A more recent approach includes WBRT combined with simultaneous integrated boost (WBRT+SIB). This study compared WBRT alone and WBRT+SIB for unresected brain metastases. One-hundred-and-three patients receiving WBRT+SIB were compared to 275 patients receiving WBRT alone for intracerebral control (IC) and overall survival (OS). Both treatment groups (WBRT alone and WBRT+SIB) were balanced with respect to patient characteristics. On multivariate analyses, WBRT+SIB (p=0.041), Karnofsky performance score (KPS) >70 (p<0.001), and 1-3 brain metastases (p=0.016) were significantly associated with IC. KPS >70 (p<0.001), favorable tumor type (p=0.011), 1-3 brain metastases (p=0.011), and absence of extracranial metastases (p<0.001) were significantly associated with OS. WBRT+SIB is associated with improved IC but similar OS when directly compared to WBRT for brain metastases. Selected patients with a high risk of intracerebral recurrence may benefit from SIB.

Prognostic factors associated with the transition in treatment methods for brain metastases from colorectal cancer.

Treatment of brain metastases (BMs) from colorectal cancer (CRC) has transitioned with the expansion of indications for stereotactic radiotherapy. Our study aimed to assess changes in prognosis and prognostic factors associated with changes in treatment for BMs from CRC. We retrospectively surveyed treatments for and outcomes of BMs from CRC in 208 patients treated during 1997-2018. Patients were divided into two groups according to time of BM diagnosis, i.e., 1997-2013 ("first period") and 2014-2018 ("second period"). We compared overall survival between the periods and assessed how the transition impacted prognostic factors affecting overall survival, including the following prognostic factors such as Karnofsky performance status (KPS), volume-related factors (BM number and diameter), and BM treatment modalities as covariates. Of the 208 patients, 147 were treated in the first period and 61 in the second period. Whole-brain radiotherapy use decreased from 67 to 39% in the second period, and stereotactic radiotherapy use increased from 30 to 62%. Median survival after BM diagnosis improved from 6.1 to 8.5months (p = 0.0272). Multivariate analysis revealed KPS, control of primary tumor, stereotactic radiotherapy use, and chemotherapy history as independent prognostic factors during the entire observation period. Hazard ratios of KPS, primary tumor control, and stereotactic radiotherapy were higher in the second period, whereas prognostic impact of chemotherapy history before BM diagnosis was similar in both periods. Overall survival of patients with BMs from CRC improved since 2014, which can be attributed to advances in chemotherapy and the more widespread use of stereotactic radiotherapy.

Survival Outcomes of Stereotactic Radiotherapy for Ten or More Brain Metastases

Abstract AIMS Discrepancies exist in the use of stereotactic radiotherapy (SRT) for patients with 10 or more brain metastases. Concerns include multiple metastases being associated with poor survival and the lack of prospective data. We analysed survival outcomes of these patients in a multi-centre cohort. METHOD We performed a retrospective cohort study of 511 consecutive patients from three SRT centres treated for brain metastases between January 2010 - August 2021, censored in January 2022. We assessed survival post-SRT of patients with ≥10 metastases against a matched group of 5-9 and 1-4 metastases using the logrank test for statistical testing. We used a multivariate Cox model to assess the relationship between overall survival and: number of metastases; total volume; primary malignancy; use of systemic anti-cancer therapies with intracranial penetrance; controlled extracranial disease. Results with p-values &amp;lt;0.05 were considered significant. RESULTS Survival data was available for all patients, and for 85-100% of factors in multivariate analysis. 63 patients had ≥10 metastases (median 19). Median survival was 13.3 months, compared with 15.1 and 19.0 months for the 5-9 and 1-4 metastasis groups respectively. Differences were not statistically significant (p-value 0.14). Increasing volume of disease (HR 1.05 [1.01-1.09], p-value: 0.01), non-small cell lung cancer (HR 3.5 [1.35-9.09] p-value: 0.01) and use of systemic anti-cancer therapy with intracranial penetrance (HR 0.239 [0.105-0.547] p-value: &amp;lt;0.01) had a statistically significant effect on survival in multivariate analysis. CONCLUSION Carefully selected patients with multiple metastases have acceptable survival outcomes following SRT and this approach should be more widely considered.

Radiotherapy for HER 2 Positive Brain Metastases: Urgent Need for a Paradigm Shift.

Simple SummaryBrain metastases (BMs) are common among patients with advanced HER2 breast cancer. The recent introduction of systemic therapy with central nervous system activity as well as the wider use of brain stereotactic radiotherapy (SRT) are contributing to improving the outcomes for these patients. In this review, we discuss a modified approach to the treatment of HER2-positive BMs from a radiation oncologist point of view, taking into consideration new advances in multimodal therapy and combinations of the most commonly used systemic treatments and brain radiation therapy (RT).Brain metastases (BMs) are common among patients affected by HER2+ metastatic breast cancer (>30%). The management of BMs is usually multimodal, including surgery, radiotherapy, systemic therapy and palliative care. Standard brain radiotherapy (RT) includes the use of stereotactic radiotherapy (SRT) for limited disease and whole brain radiotherapy (WBRT) for extensive disease. The latter is an effective palliative treatment but has a reduced effect on brain local control and BM overall survival, as it is also associated with severe neurocognitive sequelae. Recent advances both in radiation therapy and systemic treatment may change the paradigm in this subset of patients who can experience long survival notwithstanding BMs. In fact, in recent studies, SRT for multiple BM sites (>4) has shown similar efficacy when compared to irradiation of a limited number of lesions (one to three) without increasing toxicity. These findings, in addition to the introduction of new drugs with recognized intracranial activity, may further limit the use of WBRT in favor of SRT, which should be employed for treatment of both multiple-site BMs and for oligo-progressive brain disease. This review summarizes the supporting literature and highlights the need for optimizing combinations of the available treatments in this setting, with a particular focus on radiation therapy.

СТЕРЕОТАКСИЧЕСКАЯ ЛУЧЕВАЯ ТЕРАПИЯ БОЛЬНЫХ ОПУХОЛЯМИ ГОЛОВЫ И ШЕИ. СОВРЕМЕННОЕ СОСТОЯНИЕ ПРОБЛЕМЫ

This publication provides an overview of the current state of the art in the use of stereotactic radiation therapy (SBRT) for patients with head and neck tumors. We have analyzed current trends, and also presented the features of radiobiology and the basic principles of radiation treatment. Special attention is paid to indications for SBRT, fractionation schemes and radiation planning. The use of SBRT for primary head and neck tumors, including boost, as well as relapses treatment are described. The results of the implementation of SBRT by various authors both as an independent option and in combination with drug therapy are presented. The efficacy and tolerance of radiation is described in a summary form with clarifying comments. The radiation therapy toxicity profile is detailed, including the main risk factors of postradiation complications.

Assessment of semi-automated stereotactic treatment planning for online adaptive radiotherapy in ethos.

The Ethos treatment planning system allows for the rapid generation of online adaptive treatment plans while the patient is on the treatment couch. One promising application of online adaptive radiotherapy is its use in stereotactic radiotherapy. The purpose of this study was to ensure the Ethos treatment planning system (TPS) can produce clinically acceptable stereotactic plans, that are non-inferior to those from the Eclipse TPS. Forty patients that received previous stereotactic radiotherapy treatment on a Halcyon, 20 of which were lung cases, and 20 that were brain cases, were replanned using the Ethos TPS. The generated IMRT and VMAT plans were compared to the clinical Eclipse VMAT plan. This study found that the Ethos TPS can produce VMAT plans of equivalent quality (target coverage, conformity and OAR doses) to those from the Eclipse TPS for lung SBRT and brain SRT. The IMRT plans produced by the Ethos planning system were marginally inferior to Eclipse VMAT plans, with the differences likely primarily due to beam geometry rather than the optimization system. Ethos plans were generally more modulated than Eclipse plans. With careful selection of optimization structures and reduction in the body contour, VMAT plan generation time could be reduced by 87%. Ethos can generate stereotactic VMAT plans that are equivalent to those from Eclipse in the timeframe required for online adaptive radiotherapy.

Use of stereotactic radiotherapy in treatment of cerebral gliomas

The article considers statistical data on morbidity for primary tumors of the central nervous system, in particular cerebral gliomas. Significance of the problem requires a search for new ways of diagnosis and treatment of cerebral gliomas, and the article summarizes Russian and international literature on diagnosis and treatment of glial tumors. Early detection of brain tumors, appropriate molecular and genetic diagnostics and use of the latest treatment methods such as stereotactic radiotherapy, allow to achieve better long-term results, improve quality of life and lifespan of the patients.

The use of SBRT in the management of oligometastatic gynecological cancer: report of promising results in terms of tolerability and clinical outcomes.

The use of stereotactic radiotherapy (SBRT) for oligometastases is supported by several literature studies, but in the setting of gynecological malignancies, this scenario remains quite unexplored. This study reports a preliminary assessment of clinical outcomes in a cohort of 40 patients with oligometastatic gynecological neoplasms. Radiotherapy was delivered in 3-10 fractions with VMAT-IGRT technique. Toxicity was retrospectively collected according to CTCAE v4.0. Data were retrospectively collected and analyzed. Univariate and multivariate analyses were performed for assessing any potential predictive factor for clinical outcomes. A total of 63 oligometastases were treated from December 2014 to February 2021. Median age was 63years (range 30-89). Most frequent primary tumors were ovarian cancer in 42.5% and endometrium cancer in 42.5%. With a median follow-up of 27months (range 6-69), no local failures were observed, our progression-free survival rates were 43.6% and 23% at one and 2years, respectively, while 1 and 2-year overall survival rates were both 70%. No acute or late G ≥ 2 adverse events were observed. In our experience, SBRT for oligometastatic gynecological malignancies resulted in promising results in terms of clinical outcomes, with excellent local control and no evidence of severe toxicity, highlighting the effectiveness of this therapeutic option. Prospective studies to further explore this approach in this setting are advocated.

Stereotactic Radiotherapy for Oligoprogression in Metastatic Renal Cell Cancer Patients Receiving Tyrosine Kinase Inhibitor Therapy: A Phase 2 Prospective Multicenter Study

BackgroundDespite the paucity of prospective evidence, stereotactic radiotherapy (SRT) is increasingly being considered in the setting of oligoprogression to delay the need to change systemic therapy. ObjectiveTo determine the local control (LC), progression-free survival (PFS), cumulative incidence of changing systemic therapy, and overall survival (OS) after SRT to oligoprogressive metastatic renal cell carcinoma (mRCC) lesions in patients who are on tyrosine kinase inhibitor (TKI) therapy. Design, setting, and participantsA prospective multicenter study was performed to evaluate the use of SRT in oligoprogressive mRCC patients. Patients with mRCC who had previous stability or response after ≥3 mo of TKI therapy were eligible if they developed progression of five of fewer metastases. Thirty-seven patients with 57 oligoprogressive tumors were enrolled. InterventionOligoprogressive tumors were treated with SRT, and the same TKI therapy was continued afterward. Outcome measurements and statistical analysisCompeting risk analyses and the Kaplan-Meir methodology were used to report the outcomes of interest. Results and limitationsThe median duration of TKI therapy prior to study entry was 18.6 mo; 1-yr LC of the irradiated tumors was 93% (95% confidence interval [CI] 71–98%). The median PFS after SRT was 9.3 mo (95% CI 7.5–15.7 mo). The cumulative incidence of changing systemic therapy was 47% (95% CI 32–68%) at 1 yr, with a median time to change in systemic therapy of 12.6 mo (95% CI 9.6–17.4 mo). One-year OS was 92% (95% CI 82–100%). There were no grade 3–5 SRT-related toxicities. ConclusionsLC of irradiated oligoprogressive mRCC tumors was high, and the need to change systemic therapy was delayed for a median of >1 yr. Patient summaryThe use of stereotactic radiotherapy in metastatic kidney cancer patients, who develop growth of a few tumors while on oral targeted therapy, can significantly delay the need to change to the next line of drug therapy.

Overall survival after initial radiotherapy for brain metastases; a population based study of 2140 patients with non-small cell lung cancer

Background Brain metastases (BM) occur in about 30% of all patients with non-small cell lung cancer (NSCLC). BM treatment guidelines recommend more frequent use of stereotactic radiotherapy (SRT). Overall, studies report no difference in overall survival (OS) comparing SRT to whole-brain radiotherapy (WBRT). We examined survival after radiotherapy for BM in a population-based sample from the South-Eastern Norway Regional Health Authority treated 2006-2018. Methods We reviewed electronic medical records of 2140 NSCLC patients treated with SRT or WBRT for BM from 2006–2018. Overall survival (OS) was compared to predicted survival according to the prognostic systems DS-GPA and Lung-molGPA. Results Use of SRT increased during the period, from 19% (2006–2014) to 45% (2015–2018). Median OS for all patients was 3.0 months, increasing from 2.0 (2006) to 4.0 (2018). Median OS after SRT was 7.0 months (n = 435) and 3.0 months after WBRT (n = 1705). Twenty-seven percent of SRT patients and 50% of WBRT patients died within 90 days after start of RT. Age ≥70, male sex, KPS ≤70, non-adenocarcinoma histology, ECM present, multiple BM, and WBRT were associated with shorter survival (p < .001). Actual mOS corresponded best with predicted mOS by DS-GPA and Lung-molGPA for the SRT group. Conclusion Overall survival after radiotherapy (RT) for BM improved during the study period, but only for patients treated with SRT. Survival after WBRT remains poor; its use should be questioned. DS-GPA and Lung-molGPA seem most useful in predicting prognosis considered for SRT.

Prognostic value of methylation status of MGMT gene promoter in patients with glioblastoma after combination treatment.

e14025 Background: The effectiveness of radiation therapy in the classical and stereotactic treatment regimens of the primary glioblastoma multiforme was analyzed and compared. Methods: 87 patients with primary glioblastoma multiforme were hospitalized during the study period. 17 patients of them were in the treatment group (stereotactic radiotherapy, dose per fraction 2 Gy, 60 Gy total dose, CTV 2.0 cm, PTV 0.1 cm - group 1), and 70 patients were in the control group (conventionally fractionated radiotherapy, dose per fraction 2 Gy, 60 Gy total dose, CTV 2.0 cm, PTV 0.5 cm - group 2). Patients of both groups were treated with alkylating agents as the third stage of complex treatment. MGMT methylation was evaluated by pyrosequencing. Results: The use of stereotactic radiation therapy allowed to conduct a full course of treatment without interruption, whereas in the second group, due to the development of adverse reactions, the course was interrupted for 7 patients (10%). The advantage of stereotactic radiation therapy was a less pronounced increase and rapid regression of neurological deficits during treatment, manifested by better local control for 6 months. Hypermethylation of MGMT was detected in 39% of glioblastoma cases and was not detected in non-tumor tissue. The presence of promoter methylation disrupts DNA repair and is associated with longer survival in glioblastoma patients receiving alkylating agents. Note that the median survival of patients with MGMT hypermethylation in the group 1 was 285 days (IQR = 323.75), and in the group without hypermethylation was significantly more than 338.5 days (IQR = 476) (p = 0.045). A similar trend was observed in the second group: in patients with hypermethylated MGMT, the median survival was 271 days (IQR = 337), the result is different from patients without hypermethylated MGMT – 342 days (IQR = 493) (p = 0.039). Conclusions: As a result, the application of the stereotactic approach of radiation therapy in the complex treatment of patients with glioblastoma and their classification by the MGMT methylation status with a cut-off point of 10% has the basis for improving the effectiveness and tolerability of radiation therapy and contributes to the overall survival of patients.

Efficacy of salvage stereotactic radiotherapy (SRT) for locally recurrent brain metastases after initial SRT and characteristics of target population.

Due to a steadily growing use of stereotactic radiotherapy (SRT) for treatment of brain metastases (BMs), the in-field failure after an initial stereotaxy is an increasingly frequent problem. Repeat stereotactic radiotherapy (re-SRT) shows encouraging results in terms of local control. However, the evidence on prognostic factors limiting the overall survival (OS) of re-treated patients is scarce. Here, we sought to analyze the patients' and treatment characteristics influencing the survival outcomes after re-SRT. Data of all patients with local failure of initial SRT treated from 2012 to 2019 were retrospectively reviewed and cases treated with salvage SRT were analyzed. We analyzed the impact of patients' and treatment characteristics on overall survival after re-SRT by Kaplan-Meier method and Cox regression models. Local and distant brain control, cause of death, and radionecrosis rate were also assessed. Forty-seven patients with 55 BMs treated with re-SRT were evaluated. Median OS after re-SRT was 9.2months and the overall local control was 83.6%. Nine BMs (16.4%) presented local relapse (LR), 12 (21.8%) radionecrosis, while 21 patients (44.7%) developed new BMs. Only absence of extracranial metastases at BMs diagnosis (HR 0.42, CI 95%; 0.18-0.97), extracranial disease progression (HR 2.39, CI 95%; 1.06-5.38) and distant brain failure (HR 3.94, CI 95%; 1.68-9.24) after re-SRT were significantly associated with patients' survival. Extracranial progression following re-SRT was an independent prognosticator of worse OS. Re-SRT after LR presented excellent local control with acceptable RN rate and improved patients' survival, limited mainly by extracranial and distant brain progression.

A systematic review and practical considerations of stereotactic body radiotherapy in the treatment of head and neck cancer.

Stereotactic radiotherapy (SBRT) is gaining popularity although its use in head and neck cancer (HNC) is not well defined. The primary objective was to review the published evidence regarding the use of stereotactic radiotherapy in HNC. A literature search was performed by using MEDLINE and EMBASE databases for eligible studies from 2000 to 2019 and 26 relevant studies were identified. Literature demonstrates a heterogeneous use of this technique with regards to patient population, primary or salvage treatment, dose fractionation regimens, outcomes and follow-up protocols. Carotid blow out syndrome is a risk as with other forms of reirradiation but alternative treatment regimens may reduce this risk. At present there is a lack of evidence regarding SBRT as a primary treatment option for HNC and definitive answers regarding efficacy and tolerability cannot be provided but there is growing evidence that SBRT reirradiation regimens are safe and effective. In lieu of evidence from large Phase III trials, we define appropriate organ at risk constraints and prescription doses, with accurate plan summation approaches. Prospective randomised trials are warranted to validate improved treatment outcomes and acceptable treatment morbidity. This article provides a comprehensive review of evidence of use of stereotactic radiotherapy in HNC site (either as a primary treatment or as reirradiation). We also provide an evidence-based approach to the implementation and practical consideration of stereotactic radiotherapy in HNC.

Normal Tissue Dose Constraints for Multiple Lung Stereotactic Radiotherapy Treatments

Introduction: The role and use of stereotactic radiotherapy (SABR) is evolving rapidly. A key article by Hanna et al. (2017) provides an excellent overview of current evidence and suggestion of sensible dose constraints. Given the topical nature of this discussion we present a short retrospective analysis of treating multiple lung SABR patients at our centre. Method: We retrospectively analysed toxicity, both early (within 3 months of SABR) and late, and normal tissue dose constraints on all patients who had multiple lung lesions treated with SABR (using volumetric modulated arc therapy (VMAT) technique) at our tertiary centre over a 25-month period from April 2016 until May 2018. Results: We have treated 78 lung lesions in 37 patients with a combination of synchronous lung cancer primaries and lung metastases diagnoses. Median follow-up was 9 months. Almost all patients received treatment on the same day for multiple lesions. We report no grade 3 toxicities in any patient nor any unexpected side effects. 5 patients (14.7%) developed grade 2 pneumonitis. In all 5 patients, lung V12.5 was &gt;20% (range 20.8-32.2%), yet only 1 patient exceeded acceptable lung V20 constraints. Regarding long-term toxicity, 66.6% of patients reported no treatment-related effects. Of 9 patients with long-term toxicity, 8 exceeded V12.5 constraint of &lt;15%, indeed of these 5 were &gt;20%. Lung V20 levels were acceptable for the majority of these. Local control of treated lesions at median follow-up in all comers was 86.2%. Discussion: Our findings show that multiple lung SABR is tolerable, safe with minimal long-term toxicity and acceptable early toxicity. Defining normal lung V12.5 of &lt;15% (optimal) and &lt;20% (acceptable) will significantly reduce the risk of pneumonitis and longer-term toxicity, proving itself more predictive than lung V20 levels for toxicity. Additionally, treating multiple lesions concurrently appears to bare no extra risk to patients.

Brain metastases from germ cell tumor: time to reconsider radiotherapy?

The presence of brain metastases (BMs) from germ cell tumor (GCT) remains a rare situation. BMs predominantly occur among patients with testis primary tumor site, and are almost exclusively associated with non-seminomatous (NS) histologies. Two situations must be distinguished, which differ in terms of clinical presentation, overall prognostic and management. At diagnosis, BMs are almost systematically associated with extra-cerebral metastases and the cornerstone of treatment is chemotherapy, while the role of local treatment remains controversial. In the metachronous setting, BMs more frequently constitute an isolated site of relapse, the outcome is poorer, and the role of local treatment is more consensual. However, all these data widely come from old reports, with outdated radiation techniques. The recent advances in radiation oncology, especially the rising use of stereotactic radiotherapy, could lead to the reconsideration of ancient dogmas regarding the "radiosensitivity" of (NS)GCT and the role of radiotherapy among patients with BMs.

Impact of radiation dose and pre-treatment pain levels on survival in dogs undergoing radiotherapy with or without chemotherapy for presumed extremity osteosarcoma.

The purpose of this bi-institutional retrospective study was to determine whether survival for dogs with extremity osteosarcoma (OS) is improved through the use of stereotactic radiotherapy (SRT; a single fraction of 25 Gy, or 36 Gy total given in three consecutive daily fractions) plus chemotherapy, vs lower dose conventionally planned and delivered hypofractionated radiotherapy (CHRT; 14-20 Gy total in 1-2 consecutive daily fractions) plus chemotherapy. We also sought to determine whether baseline pain severity influences oncologic outcomes following radiotherapy for canine extremity OS. The medical records of 82 dogs undergoing radiotherapy for confirmed or presumed OS were reviewed. In dogs receiving combinations of both chemotherapy and radiotherapy, survival was significantly longer with SRT vs CHRT (median overall survival time: 350 vs 147 days; P = .031). In a univariate analysis, dogs with pulmonary metastases and high pain at the time of irradiation had short overall survival times; use of high radiation doses and chemotherapy were associated with improved survival. Separate multivariable models were built to assess the predictive nature of various factors that might influence event-free or overall survival in dogs treated with radiotherapy, with or without chemotherapy; for dogs treated with both chemotherapy and radiotherapy, overall survival times were significantly longer when baseline pain scores were 'low' (vs 'high'; hazard ratio: 0.258; P = .030), radiation doses were high (hazard ratio: 0.943; P = .034). Neither pain nor radiation dose were associated with survival in dogs treated with radiotherapy, without chemotherapy.

Analysis of a Surgical Series of 21 Cerebral Radiation Necroses

There is no standard approach to differentiate cerebral radiation necrosis from tumor recurrence and no standard treatment pathway for symptomatic lesions. In addition, reports on histology-proven radiation necrosis and the underlying pathophysiology are scarce and highly relevant. Our monocentric, retrospective analysis included 21 histology-proven cerebral radiation necroses. Our study focused on 1) potential risk factors for the development of radiation necrosis, 2) radiologic and histopathologic features of individual necroses, and 3) the suitability of previously reported magnetic resonance imaging (MRI)-based methods to identify radiation necroses based on specific structural image features. Average time between radiation treatment and development of necrosis was 4.68 years (95% confidence interval, 0.19-9.55 years). Matching available MRI data sets with those of patients with tumor lesions, we compared specificity and sensitivity of 3 previously reported methods to identify radionecrosis based on imaging criteria. In our hands, none of these methods reached a sensitivity ≥70%. Radionecrosis presented with large edema and showed increased levels of cell proliferation, as inferred by Ki-67 staining. Surgical removal of radiation necrosis proved to be a safe approach with low permanent morbidity (<5%) and no mortality. Although the overall incidence of cerebral radiation necrosis is low, our data suggest an increasing incidence over the last 2 decades, which is likely associated with the use of stereotactic radiotherapy. There are no imaging standards to identify radiation necrosis on standard MRI with structural sequences. Surgical removal of radiation necrosis is associated with low morbidity and mortality.

The Novel Use of Stereotactic Radiotherapy for Remnant Adrenal Tissue in Nelson Syndrome

Recurrent Cushing disease (CD) is a rare complication that occurs in patients who have undergone bilateral adrenalectomy (BLA). We report a case of recurrent CD in a patient with Nelson syndrome and adrenalectomy due to remnant adrenal tissue, and a novel treatment strategy using stereotactic body radiation therapy (SBRT) to the adrenal glands. We report a case of recurrent CD in a woman with Nelson syndrome and adrenalectomy and describe her clinical course and management. We also include a literature review of CD management and adrenal radiation. The patient had persistent pituitary CD despite pituitary surgery and radiosurgery and underwent BLA. She developed recurrent CD due to a remnant adrenal gland post adrenalectomy. She then underwent SBRT to both adrenal beds to treat the remnant adrenal tissue. Her serum cortisol dropped rapidly after adrenal radiation and she experienced minimal side effects. She has been in remission for over 2 years. This is the first reported case of recurrent CD in a patient post adrenalectomy that was successfully treated with SBRT to the remnant adrenal tissue.