Marek Slávik

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.

MicroRNAs Involvement in Radioresistance of Head and Neck Cancer

Resistance to the ionizing radiation is a current problem in the treatment and clinical management of various cancers including head and neck cancer. There are several biological and molecular mechanisms described to be responsible for resistance of the tumors to radiotherapy. Among them, the main mechanisms include alterations in intracellular pathways involved in DNA damage and repair, apoptosis, proliferation, and angiogenesis. It has been found that regulation of these complex processes is often controlled by microRNAs. MicroRNAs are short endogenous RNA molecules that posttranscriptionally modulate gene expression and their deregulated expression has been observed in many tumors including head and neck cancer. Specific expression patterns of microRNAs have also been shown to predict prognosis and therapeutic response in head and neck cancer. Therefore, microRNAs present promising biomarkers and therapeutic targets that might overcome resistance to radiation and improve prognosis of head and neck cancer patients. In this review, we summarize the current knowledge of the functional role of microRNAs in radioresistance of cancer with special focus on head and neck cancer.

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.

Metastases of a Breast Cancer to Skull Base

BACKGROUND Breast cancer (BC) is a frequent malignant disease which tends to develop distant metastases, but only very rarely in the head and neck region. CASE REPORT We present two case reports of patients with metastases of invasive BC in this area. They are of different clinical manifestation with different time relation to the primary tumor and different symptomatology. In the case of the first patient, a few years without evidence of malignant disease after treatment of primary tumor in complete remission. In the case of the second patient, as the first symptom of undiagnosed disease. Metastases were clinically observed in the skull base and maxillary sinus, manifesting neurologically with foramen jugulare syndrome and orbital symptoms, resp. In both cases, correlations between histological and clinical findings were essential for diagnosis. Palliative multimodal treatment was then employed. CONCLUSION Metastases of BC in the head and neck region occur only very rarely. The extremely variable symptomatology depends on the location of the metastasis and the affected structures. This might be a pitfall for diagnostics, especially in cases of an unidentified primary breast tumor, which may result in a delay of correct diagnosis. In addition, the correlation between histopathological and clinical findings might be of great relevance in these cases. Key words: skull base metastasis - breast cancer - foramen jugulare syndrome.

Prognostic impact of combined immunoprofiles in oropharyngeal squamous cell carcinoma patients with respect to AJCC 8th edition

OBJECTIVES To examine combined immunoprofiles of epidermal growth factor receptor (EGFR), CD44, and p16 in oropharyngeal squamous cell carcinoma (OPSCC) and to correlate them with radiotherapy treatment outcomes and clinicopathological parameters. Prognostic impact of the American Joint Committee on Cancer (AJCC) 8th edition staging system in comparison with 7th edition was analyzed. METHODS The study included 77 OPSCC patients treated by definitive intensity-modulated radiotherapy (IMRT). Clinical staging was assessed according to the AJCC, both 7th and 8th edition. Immunohistochemical (IHC) analysis of CD44 and EGFR was performed on primary biopsy tumor tissues. To evaluate the HPV status, IHC detection of p16 was employed. RESULTS The AJCC 8th edition staging system revealed correlations between overall survival (OS), progression-free survival (PFS), locoregional control (LRC), and clinical stage. EGFR and CD44 positivity (+) and p16 negativity (-) were associated with clinical stage IV of the disease. CD44+ and EGFR+ OPSCC displayed worse OS and LRC, and these cases also showed the worst 3-year OS and LRC. Combined analysis of protein expressions identified an association between p16- and EGFR+, p16- and CD44+, EGFR+, and CD44+. Combined immunoprofiles CD44+/p16-, EGFR+/p16-, and EGFR+/CD44+ were associated with worst OS and LRC. CONCLUSIONS Combined immunoprofiles of p16, EGFR, and CD44 might provide valuable prognostic and predictive information for the individual OPSCC patients, especially in terms of response to IMRT and prediction of treatment outcomes. Application of the AJCC 8th edition staging for HPV+ OPSCC proved to improve hazard discrimination and prognostication of OPSCC.

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.