Petr Burkon

Why and how to spare the hippocampus during brain radiotherapy: the developing role of hippocampal avoidance in cranial radiotherapy

The goal of this review is to summarize the rationale for and feasibility of hippocampal sparing techniques during brain irradiation. Radiotherapy is the most effective non-surgical treatment of brain tumors and with the improvement in overall survival for these patients over the last few decades, there is an effort to minimize potential adverse effects leading to possible worsening in quality of life, especially worsening of neurocognitive function. The hippocampus and associated limbic system have long been known to be important in memory formation and pre-clinical models show loss of hippocampal stem cells with radiation as well as changes in architecture and function of mature neurons. Cognitive outcomes in clinical studies are beginning to provide evidence of cognitive effects associated with hippocampal dose and the cognitive benefits of hippocampal sparing. Numerous feasibility planning studies support the feasibility of using modern radiotherapy systems for hippocampal sparing during brain irradiation. Although results of the ongoing phase II and phase III studies are needed to confirm the benefit of hippocampal sparing brain radiotherapy on neurocognitive function, it is now technically and dosimetrically feasible to create hippocampal sparing treatment plans with appropriate irradiation of target volumes. The purpose of this review is to provide a brief overview of studies that provide a rationale for hippocampal avoidance and provide summary of published feasibility studies in order to help clinicians prepare for clinical usage of these complex and challenging techniques.

Post-WBRT cognitive impairment and hippocampal neuronal depletion measured by in vivo metabolic MR spectroscopy: Results of prospective investigational study

BACKGROUND AND PURPOSE The aim of this prospective study is to evaluate post-whole brain radiotherapy (WBRT) changes in hippocampal concentration of N-acetylaspartate (h-tNAA) as a marker of neuronal loss and to correlate those changes to neurocognitive function. MATERIAL AND METHODS Thirty-five patients with brain metastases underwent baseline single slice multi-voxel MR spectroscopy (MRS) examination for measurement of hippocampal h-tNAA together with baseline battery of neurocognitive tests focused on memory (Auditory Verbal Learning Test and Brief Visuospatial Memory Test - Revised) as well as quality of life questionnaires (EORTC QLQ-C30 a EORTC QLQ-BN20). Eighteen patients completed follow-up evaluation four months after standard WBRT (2 laterolateral fields, 10×3.0Gy, 6MV photons) and were included in this analysis. MRS and cognitive examinations were repeated and compared to baseline measurements. RESULTS Statistically significant decreases in h-tNAA were observed in the right (8.52-7.42mM; -12.9%, 95%CI: -7.6 to -16.4%) as well as in the left hippocampus (8.64-7.60mM; -12%, 95%CI: -7.9 to -16.2%). Statistically significant decline was observed in all AVLT and BVMT-R subtests with exception of AVLT_Recognition. Quality of life declined after WBRT (mean Δ -14.1±20.3 points in transformed 0-100 point scale; p=0.018) with no correlation to changes in hippocampal metabolite concentrations. Moderate positive correlation was observed between left h-tNAA concentration decrease and AVLT_TR decline (r=+0.32; p=0.24) as well as with AVLT_DR (r=+0.33; p=0.22) decline. Changes in right h-tNAA/Cr negatively correlated with AVLT_DR (r=-0.48; p=0.061). No correlation between right hippocampus h-tNAA and memory decline (AVLT) was observed. CONCLUSIONS Our results suggest hippocampal NAA concentrations decline after WBRT and MRS may be a useful biomarker for monitoring neuronal loss after radiotherapy.

Patterns of failure after brain metastases radiotherapy: reflections on the importance for treatment and clinical trials reporting

In many ongoing clinical trials, new strategies for radiotherapy of brain metastases are currently being investigated. A post surgical focal cavity stereotactic radiosurgery and the developing role of a hippocampal-sparing whole brain radiotherapy are of the highest importance. The evaluation of spatial patterns of metastases failure after radiotherapy is a powerful tool for assessing the potential benefit of new different radiotherapy approaches, which enables to identify possible directions leading to better radiotherapy techniques and to modify general management for newly diagnosed brain metastases. The purpose of this article is to present a mix between trial data and philosophical point of view for discussion about the importance of systematic evaluation of spatial patterns of failure in all ongoing trials investigating new approaches in local brain metastases treatment.

Radiotherapy of glioblastoma 15 years after the landmark Stupp’s trial: more controversies than standards?

Abstract Background The current standard of care of glioblastoma, the most common primary brain tumor in adults, has remained unchanged for over a decade. Nevertheless, some improvements in patient outcomes have occurred as a consequence of modern surgery, improved radiotherapy and up-to-date management of toxicity. Patients from control arms (receiving standard concurrent chemoradiotherapy and adjuvant chemotherapy with temozolomide) of recent clinical trials achieve better outcomes compared to the median survival of 14.6 months reported in Stupp’s landmark clinical trial in 2005. The approach to radiotherapy that emerged from Stupp’s trial, which continues to be a basis for the current standard of care, is no longer applicable and there is a need to develop updated guidelines for radiotherapy within the daily clinical practice that address or at least acknowledge existing controversies in the planning of radiotherapy. The goal of this review is to provoke critical thinking about potentially controversial aspects in the radiotherapy of glioblastoma, including among others the issue of target definitions, simultaneously integrated boost technique, and hippocampal sparing. Conclusions In conjunction with new treatment approaches such as tumor-treating fields (TTF) and immunotherapy, the role of adjuvant radiotherapy will be further defined. The personalized approach in daily radiotherapy practice is enabled with modern radiotherapy systems.

Second cancers in Hodgkin's lymphoma long-term survivals: A 60-year single institutional experience with real-life cohort of 871 patients

Appropriate surveillance guidelines for patients after successful treatment of Hodgkins lymphoma (HL) are needed to reduce mortality of iatrogenic secondary cancers (SC). This large single institutional retrospective study analyses the risk of SC in HL patients treated outside of clinical trials over past decades.

Toxicity and survival outcomes of adjuvant chemoradiation for gastric and gastroesophageal junction cancer patients treated in period 2006-2009: an institutional experience.

Surgical resection is the mainstay of gastric or gastroesophageal junction cancer treatment and has curative potential for patients with early-stage disease. In order to improve the poor survival rates, there are two complementary treatment strategies used at most - perioperative chemotherapy based on UK Magic trial or adjuvant chemoradiation based on INT-0116 trial. Daily treatment decision making should be led also by institutional experiences with toxicity evaluation. We evaluated survival and toxicity outcomes of 47 consecutive patients who underwent adjuvant chemoradiation in our institution in the years 2006-2009. 45Gy in 5 weeks with concurrent two cycles of FUFA Mayo regimen chemotherapy were administrated as part of combined treatment. The acute toxicity was relatively mild (CTCAE scale): grade 2 nausea in 26%, vomiting in 13%, and diarrhoea grade 1 in 15% and general abdominal discomfort in 57% of patients. Grade 3 haematological and infectious complications in 6% and 2% respectively. Late adverse events were as follows: grade 1 esophageal toxicity in 17%, signs of mild chronic esophageal ulceration and esophageal stenosis in 9% of patients (50% of them had tracheoesophageal fistula). The Kaplan- Meier estimate of the median overall survival was 30.5 months with median 25.7 months disease free survival. The overall survival was statistically significantly affected by the amount of removed positive lymph nodes. For the proper evaluation of radiotherapy role in multimodal treatment approach, results of other clinical trials investigating role of concurrent radiotherapy in administration of perioperative chemotherapy will be necessary. Meanwhile, two equally approaches are possible, all having their pros and cons. Institutional toxicity evaluation is recommended in order to provide the best care possible. Keywords: adjuvant chemoradiation, gastric cancer, early toxicity, late toxicity, survival outcomes.