Local control and radionecrosis of brain metastases from non-small-cell lung cancer treated by hypofractionated stereotactic radiotherapy: Evaluation of predictive factors.

Background: The objective of our study was to report predictive factors of local control (LC) and radionecrosis (RN) of brain metastases (BM) of non-small cell lung carcinoma (NSCLC) treated by multifractionated stereotactic radiotherapy (MF-SRT) according to French recommendations. Method: From 2012 to 2020, 87 patients with 101 BM were retrospectively included. The median age was 63 years (37-85). GTV was defined using contrast-enhanced T1w MRI and was isotropically extended by 2 mm to form PTV. Mean maximum BM diameter was 24.5 mm (10-46). Patients were treated with dynamic arctherapy from May 2012 to February 2016 and then with VMAT. The total prescribed dose was 23.1 Gy prescribed to the encompassing 70% isodose, in 3 fractions. Results: LC rates at 6 months, 1 year and 2 years was 95.7%, 90.7% and 87.9% respectively. In multivariate analysis, high GTV Dmin (HR = 0.822, p = 0.012) was in favor of better LC whereas a large maximum diameter was predictive of poor LC (HR = 1.124, p = 0.02). GTV Dmin of 27.4 Gy was identified as a discriminant threshold of LC. In case of GTV Dmin ≥ 27.4 Gy, LC at 1 year was 95.3% versus 75.1% with GTV Dmin < 27.4 Gy. Cumulative incidence of RN at 6 months, 1 year and 2 years was 6.3%, 15.4% and 18.1%, respectively. In multivariate analysis, only dyslipidemia was predictive of RN (HR = 2.69, p = 0.03). No dosimetric predictive factor of RN was found in our study. Conclusion: MF-SRT (3x7.7 Gy on 70% isodose line, with PTV = GTV + 2 mm; according to French recommendations) of BM from NSCLC gives high LC rates with acceptable RN rate. A GTV Dmin of at least 27.4 Gy could be proposed to optimize dosimetric objectives. No dosimetric predictive factors of RN were found in this study. However, dyslipidemia was identified as a potential predictive factor of RN.

[Place of Linacs in extracranial stereotactic radiotherapy: Are they now equivalent to Cyberknife®?] / Place des Linacs dans la radiothérapie stéréotaxique extra crânienne : sont-ils désormais non inférieurs au Cyberknife® ?

Extracranial stereotactic radiotherapy has developed recently, since the years 1990-2000. Devices specifically dedicated to this type of treatment were then developed and shared the favors of radiation oncologists: Tomotherapy® and especially Cyberknife®, which offered the advantage of "tracking" with the possibility of real time motion correction, allowing an increase in the precision of targeting volumes. Recently, the latest generations of linear accelerators (Linac) have been developed, integrating much higher dose rates, an improved ballistic precision with a very short treatment duration time and the possibility of real time motion management (with notably the possibility of adaptive radiotherapy in real time with the development of "MLC tracking"). So are Linacs able to perform equivalent (not inferior) extracranial stereotactic radiotherapy treatments to those with Cyberknife®, the historical gold standard in this field? This article presents a comparison of these two treatment devices, by successively considering dose distributions in the irradiated volume, distant received doses from this volume (including the "integral dose"), problems linked to the duration of the sessions and those linked to motion management.

Preoperative stereotactic radiosurgery for brain metastases: the STEP study protocol for a multicentre, prospective, phase-II trial.

BACKGROUND: Surgery is an important therapeutic option for brain metastases. Currently, postoperative stereotactic radiosurgery (SRT) leads to 6-month and 1-year local control estimated at 70 and 62% respectively. However, there is an increased risk of radio-necrosis and leptomeningeal relapse. Preoperative SRT might be an alternative, providing local control remains at least equivalent. It is an innovative concept that could enable the stereotactic benefits to be retained with advantages over post-operative SRT. METHODS: STEP has been designed as a national, multicentre, open-label, prospective, non-randomized, phase-II trial. Seventeen patients are expected to be recruited in the study from 7 sites and they will be followed for 12 months. Patients with more than 4 distinct brain metastases, including one with a surgical indication, and an indication for SRT and surgery, are eligible for enrolment. The primary objective of the trial is to assess 6-month local control after preoperative SRT. The secondary objectives include the assessment of local control, radio-necrosis, overall survival, toxicities, leptomeningeal relapse, distant control, cognitive function, and quality of life. The experimental design is based on a Flemming plan. DISCUSSION: There is very little data available in the literature on preoperative SRT: there have only been 3 American single or two-centre retrospective studies. STEP is the first prospective trial on preoperative SRT in Europe. Compared to postoperative stereotactic radiotherapy, preoperative stereotactic radiotherapy will enable reduction in the irradiated volume, leptomeningeal relapse and the total duration of the combined treatment (from 4 to 6 weeks to a few days). TRIAL REGISTRATION NUMBER: Clinicaltrials.gov: NCT04503772 , registered on August 07, 2020. Identifier with the French National Agency for the Safety of Medicines and Health Products (ANSM): N°ID RCB 2020-A00403-36, registered in February 2020. PROTOCOL: version 4, 07 December 2020.

Significant correlation between gross tumor volume (GTV) D98% and local control in multifraction stereotactic radiotherapy (MF-SRT) for unresected brain metastases.

BACKGROUND: Stereotactic radiotherapy (SRT) should be applied with a biologically effective dose with an α/ß of 12 (BED12) ≥ 40 Gy to reach a 1-year local control (LC) ≥ 70%. The aims of this retrospective study were to report a series of 81 unresected large brain metastases treated with Linac-based multifraction SRT according to the ICRU 91 and to identify predictive factors associated with LC. METHODS: Included in this study were the first 81 brain metastases (BM) consecutively treated with Linac-based volumetric modulated arc therapy (VMAT) multifraction SRT from 2017 to 2019. The prescribed dose was 33 Gy for the GTV and 23.1 Gy (70% isodose line) for the PTV in 3 fractions (3f). Mean BM largest diameter and GTV were 25.1 mm and 7.2 cc respectively. Mean follow-up was 10.2 months. RESULTS: LC was 79.7% and 69.7% at 1 and 2 years respectively. Significant predictive factors of LC were GTV D98% (HR = 0.84, CI 95% = 0.75-0.95, p = 0.004) and adenocarcinoma as the histological type (HR = 0.29, CI 95% = 0.09-0.96, p = 0.042) in univariate and multivariate analysis. A threshold of 29 Gy for GTV D98% was significantly correlated to LC (1-year LC = 91.9% for GTV D98% ≥ 29 Gy vs 69.6% for GTV D98% < 29 Gy (p = 0.030)), corresponding to a BED12 = 52.4 Gy. No tumor progression was observed for a BED12 ≥ 53.4 Gy, corresponding to a GTV D98% ≥ 20 Gy /1f and GTV D98% ≥ 29.4 Gy 3f. Median OS was 15 months. Symptomatic radionecrosis occurred in 4.9% of cases. CONCLUSION: The GTV D98% is a strong reproducible significant predictive factor of LC for brain SRT. Dose prescription should lead to a GTV BED12 98% ≥ 52.4-53.4 Gy to significantly improve LC, corresponding to respectively a GTV D98% ≥ 19.7-20 Gy/1f and 29-29.4 Gy/3f.

Stereotactic Radiosurgery for Vestibular Schwannomas: Reducing Toxicity With 11 Gy as the Marginal Prescribed Dose.

BACKGROUND: Stereotactic radiosurgery (SRS) is a common treatment option for vestibular schwannomas. Historically, a dose de-escalation of the marginal prescribed dose from 16 Gy to 12-13 Gy has been done to limit toxicity without reducing local control (LC). We aimed to retrospectively report outcomes of Linac-based SRS for vestibular schwannomas treated with different doses. METHODS: Included in the study were 97 stage 1 (1%), 2 (56%), 3 (21.5%), and 4 (21.5%) vestibular schwannomas treated with Linac-based (Novalis®) SRS from 1995 to 2019. No margin was added to the GTV to create the PTV. The median marginal prescribed dose was 14 Gy (range: 12-16 Gy) before 2006 and then 11 Gy for all patients (61 pts). Mean tumor volume was 1.96 cm3, i.e., about 1.6 cm in diameter. Mean follow-up was 8.2 years. RESULTS: Following SRS, LC at 3, 5, and 10 years was 100%, 98.4%, and 95.6%, respectively [100% for those with ≤ 13 Gy as the marginal prescribed dose (NS)]. Toxicity to the trigeminal nerve was reported in 7.2% of cases (3.3% and 0% for transient and permanent toxicity for 11 Gy). The marginal prescribed dose was the only significant predictive factor in univariate and multivariate analysis (HR = 1.77, 95% CI = 1.07-3.10, p = 0.028). Toxicity to the facial nerve was reported in 6.2% of cases. The marginal prescribed dose was again the only significant predictive factor in univariate and multivariate analysis (HR = 1.31, 95% CI = 0.77-2.23, p = 0.049). CONCLUSION: Linac-based SRS for stages 1-3 vestibular schwannomas provides excellent outcomes: a 10-year LC rate of over 95%, with a permanent facial or trigeminal toxicity rate of under 5%. A marginal prescribed dose of 11 Gy seems to decrease nerve toxicity and facial toxicity in particular, without reducing LC. Prospective studies with longer follow-up are needed.

Significant Correlation Between Overall Survival and Mean Lung Dose in Lung Stereotactic Body Radiation Therapy (SBRT).

BACKGROUND: After stereotactic body radiation therapy (SBRT) for medically inoperable stage I non-small-cell lung cancer (NSCLC), more patients die of comorbidities, particularly severe pulmonary insufficiency, than of tumor progression. The aim of this study was to evaluate correlation between lung biologically effective dose (BED) with an α/ß ratio of 3 Gy (BED3) and overall survival (OS) for these patients. METHODS: From 2012 to 2017, we have developed a prospectively updated institutional database for all first 100 consecutively treated patients with inoperable Stage 1 (T1T2N0M0) NSCLC. All SBRT were conducted on a Novalis Tx® LINAC with two coplanar dynamic conformal arcs (84%) or with coplanar volumetric modulated arc therapy (VMAT) (16%). Mean GTV and PTV were 8.6 cc and 50.8 cc, respectively. The marginal dose prescribed to the PTV was the 80% isodose line (IDL), i.e., 54 Gy in 3 fractions for 76 patients (BED10 = 126 Gy) and 50 Gy in 5 fractions for 24 patients (BED10 = 83.3 Gy). Pulmonary heterogeneity has been taken into account by using Monte Carlo or AAA algorithms. Median follow-up was 25 months. RESULTS: At 1, 2, 3 and 5 years, local control (LC) was respectively 100, 98.2, 98.2, and 77.7%, and OS was respectively 83, 71.2, 58.1, and 33.2% (median OS was 49 months). Significant OS prognostic factors in univariate and multivariate analysis were mean lung BED3 (HR = 1.14, p = 0.01) and PTV volume (HR = 1.01, p = 0.004). A mean lung BED3 ≤ 5 Gy was significantly associated with a doubling of median OS from 29 months to more than 60 months (not achieved, p = 0.0068). For patients with a forced expiratory volume in 1 second (FEV1) ≤ 40%, a mean lung BED3 ≤ 4 Gy was significantly associated with a doubling of median OS from 23 to 46 months (p = 0.019). CONCLUSION: Mean lung BED3 is strongly and significantly associated with OS in SBRT for inoperable Stage I NSCLC. For all treated patients, a mean lung BED3 ≤ 5 Gy lead to a doubling of median OS. This threshold value should be reduced to 4 Gy for patients with FEV1 ≤ 40%.

Multiple sclerosis as differential diagnosis of radionecrosis for post-irradiation brain lesions: A case report.

INTRODUCTION: Demyelination can occur after brain radiotherapy in tissue adjacent to irradiated tumours. To date, no correlation has been found between conventional-dose radiotherapy and the development of multiple sclerosis, but radiotherapy could be a triggering factor among women with known multiple sclerosis. To the best of our knowledge, this is the first well-documented case of this association with a dosimetric analysis. CASE PRESENTATION: The case we report here describes the development of multiple sclerosis in a 36-year-old woman without significant past medical history 3 months after the last session of fractionated stereotactic radiotherapy for a pituitary macroadenoma. Our dosimetric analysis suggests that all the multiple sclerosis lesions occurred in the brain regions irradiated with a mean biologically effective dose (BED2) of 33.9 Gy (27.3-49.6 Gy). CONCLUSION: Consequently special caution towards radiotherapy is required among patients with demyelinating illnesses or for 35-45-year-old women who are at risk. In addition, multiple sclerosis lesions can look like metastases. We should therefore keep differential diagnoses in mind in order not to make mistakes that would delay treatment.

Patterns of Failure After Linear Accelerator Radiosurgery for Cerebral Arteriovenous Malformations.

BACKGROUND: Numerous studies have assessed the predictive factors for the arteriovenous malformation (AVM) response to stereotactic radiosurgery (SRS). However, only a few have discussed the causes of failure. The aim of the present study was to evaluate the patterns of failure in patients with AVM who had undergone linear accelerator SRS. METHODS: We performed a retrospective analysis of 288 patients who had undergone linear accelerator SRS in our institution from 1995 to 2011. Failure was defined from the findings of the follow-up angiogram at 5 years, with failure identified in 44 patients. The distribution of causes was estimated using a descriptive analysis of literature-based causes, including a minimal margin dose of <18 Gy, a residual nidus outside the initial targeted volume, previous embolization, recanalization, and the size of the target volume. We also analyzed the associations among the causes. RESULTS: Incomplete nidus identification (41%) and previous embolization (77%) were the most frequently observed conditions in patients with failure. Patients who had undergone previous embolization, for whom the cause of failure had always been identified (P = 0.001), were younger (P = 0.004) and had had a larger nidus volume (P = 0.025). Recanalization was rare (5 of 34 patients) and had occurred exclusively in women (P = 0.048). Larger nidus volumes were less frequent (mean, 2.18 ± 2.2 cm3; range, 0.13-10.8 cm3) and had been observed mainly in women when >2 cm3 (P = 0.012). An insufficient dose was observed in 9 patients and had occurred in the case of a larger volume (P = 0.031), which had resulted in dosimetry constraints in 3 patients and treatment in the vicinity of eloquent zones in 6 patients. No known cause was found in 5 patients, 4 of whom had had a low Spetzler-Martin grade (I and II; P = 0.003), suggestive of radioresistance. CONCLUSION: The results of our detailed analysis have highlighted the distribution of the causes of failure and the potential role of radioresistance in treatment failure.

Second course of stereotactic radiosurgery for locally recurrent brain metastases: Safety and efficacy.

In the present study, we have evaluated the efficacy and toxicity of repeated brain metastases (BM) stereotactic radiosurgery (SRS2) following local failure of a prior radiosurgical procedure (SRS1). Between December 1996 and August 2015, 30 patients with 36 BM underwent SRS2 with a median dose of 18Gy. All BM were located outside critical structures. Following SRS2, local control at 6 months and one year were respectively 82.9% (IC 95%: 67.6-91.9) and 67.8% (IC 95%: 51-81). On multivariate analysis, planning target volume (PTV) < 3cc (HR: 0.19 (0.1-0.52)) and whole brain radiotherapy (WBRT) prior to SRS2 (HR: 0.25 (0.1-0.64)) were significantly associated with a better local control. One- and two-year overall survival rates after SRS2 were respectively 65.5% (IC 95%: 47.3-80%) and 27.6% (IC 95%: 14.7-45.7). Median overall survival following SRS2 was 14.2 months (range 1-106). Nineteen (63%) patients died from progressive systemic disease. Three (10%) patients died from out-field progressive brain disease and 8 (27%) in-field. Concerning toxicities, edema, radionecrosis, and hemorrhages were identified in 5 (12.8%), 4 (10.2%), and 5 (12.8%) patients respectively. No toxicity resulted in a neurological deficit. On univariate analysis, toxicities were significantly associated with PTV > 7cc (p = 0.02) and all patients had a WBRT before SRS2. A second course of SRS for locally recurrent brain metastases showed encouraging rates of local control. This treatment led to acceptable toxicities, especially for brain metastases smaller than 7cc, in our selected cohort of patients with BM located outside critical structures. Further studies are needed.

[Bisphosphonate and denosumab-related osteonecrosis of the jaw: Epidemiology, diagnosis and management]. / Ostéonécrose des maxillaires liée aux bisphosphonates et denosumab : épidémiologie, diagnostic et traitement.

Bisphosphonate-related osteonecrosis of the jaw have been widely described. Denosumab has recently been associated to ONJ. Guidance to clinicians is based on criteria established by the American Association of Oral and Maxillofacial Surgeons (AAOMS). Treatment should be multidisciplinary. Two options are available and have to be discussed on the basis of associated therapeutic, patient's general state of health and possibility of therapeutic window during cancer treatment: conservative (medication and conservative surgery like superficial debridement) and extensive surgery. Therefore, we report an update about management strategies of osteonecrosis of the jaw and two cases of patients with a stage 2 osteonecrosis of the jaw only treated with mouth rinses, antibiotics and debridement and complete healing.