P05.05.B A new IDH-wildtype glioma subtype characterized by highly diffuse growth pattern, distinct epigenetic profile and relatively favorable prognosis

Background

DNA methylation profiling has emerges as a powerful approach to CNS tumor classification and the discovery of novel, molecularly distinct entities. With the release of the 12.5 version of the Heidelberg Brain Tumor Classifier, some unclassifiable cases can be assigned to novel methylation classes. We retrospectively reviewed our databases and identified 16 previously unclassifiable cases, all of which belong to the provisional methylation class “adult-type diffuse high-grade glioma, IDH-wildtype, subtype F (HGG_F)”.

Material and Methods

We clinically, radiologically and morphologically characterized 16 HGG_F cases and compared them to 347 glioblastomas. We additionally analyzed copy-number alterations and performed DNA exome sequencing.

Results

Median age at diagnosis of the 12 males and 4 females was 65 years. Upon initial diagnostic workup, specimens were classified as CNS tissue with reactive changes (n=3) or suspicious for the infiltration zone of a diffuse glioma (n = 13). None of the cases demonstrated endothelial proliferation or necrosis and 10/16 tumors had flat copy number profiles. Radiological characteristics were reminiscent of gliomatosis cerebri in eight cases and 9/9 cases had normal FET-PET scans. Whole-exome sequencing revealed genetic alterations frequently found in IDH-wildtype glioblastomas, including TERT promoter mutations in 11/14 (78.6%) and PIK3 mutations (10/14, 71.4%). Outcome was significantly better compared to TCGA IDH-wildtype glioblastomas with a median progression-free survival of 58 months and overall survival of 73 months (both p<0.001).

Conclusion

We provide evidence that TERT promoter mutations in diffusely infiltrating gliomas without further morphological or molecular signs of high-grade glioma should be interpreted in the context of the clinico-radiological presentation as well as epigenetic prolife and may not be suitable as standalone diagnostic marker for glioblastoma, IDH wildtype.

Typing of inflammatory lesions of the pituitary

Inflammatory pituitary lesions account for 1.8% of all specimens from the German Pituitary Tumor Registry. They occure in 0.5% of the autoptical specimens and in 2.2% of the surgical cases. Women are significantly more often affected than men and are often younger when first diagnosed. In general, primary and secondary inflammation can be distinguished, with secondary types occurring more frequently (75.1%) than idiopathic inflammatory lesions (15.4%). In primary inflammation, the lymphocytic type is more common (88.5%) than the granulomatous type of hypophysitis (11.5%). The most common causes of secondary inflammation are Rathke's cleft cysts (48.6%), followed by tumors (17.4%) such as the craniopharyngioma (9.1%), adenoma (5.5%) or germinoma (2.0%). More causes are tumor-like lesions (7.1%) such as xanthogranuloma (3.5%) or Langerhans histiocytosis (3.5%), abscesses (5.5%), generalized infections (5.1%), spreaded inflammations (4.7%) and previous surgeries (4.0%). In 1.6% of all specimens the reason for the inflammation remains unclear. The described classification of hypophysitis is important for specific treatment planning after surgery.

Abstract P3-07-55: Predictive value of O6-methylguanine-DNA methyltransferase (MGMT) promoter gene methylation in triple-negative breast cancer patients receiving carboplatin

Background: The epigenetic profile of triple-negative breast cancer (TNBC) showed a wide prevalence of MGMT promoter methylation.Aberrant methylation of MGMT seems to be an independent predictor of poor survival in patients with basal-like breast cancer. Moreover, patients with MGMT-negative basal-like tumors who received cyclophosphamide had asignificantly improved DFS and OS compared with MGMT-positive tumors.However, the impact of MGMT methylation in the context of modern therapy concepts is not clear.

Methods: We retrospectively evaluated 174 TNBC tumors of patients enrolled into the neoadjuvantGeparSixtotrial from 08/2011 to 12/2012. Patients were randomized to receive 18 weeks of neoadjuvant treatment with paclitaxel (80mg/m2/week) and non-pegylated liposomal doxorubicin (20mg/m2/week) with or without addition of carboplatin (AUC 2.0-1.5/week).Hormone-receptor status, HER2status, and Ki67 were centrally confirmed prior to randomization. We defined pathological complete response (pCR)as ypT0/is ypN0. MGMT promoter methylation status was determined by PCR using EZ DNA Methylation Kit™ (Zymo Research); TNBCtumors were considered to be methylated if they had an average methylation ≥10%, some tumors were considered borderline due to high heterogeneity among GpC islands.We investigated the effect of MGMT methylation on pCR and its correlation with baseline characteristics.

Results: A total of210 tumors from the TNBC cohort of the GeparSixtotrial(n=315) were available with a tumor content >20%. In 174 tumors the methylation assay was performed successfully. The number of tumorswith methylated MGMT was similar in carboplatin vs. non-carboplatin treated cohorts. In the carboplatin group 19.3% (17/88) of TNBC were methylated, 65.5% (58/88)unmethylated, and 14.8% (13/88) borderline.In the non-carboplatin group 20.9% (18/86) of TNBC were methylated, 62.8% (54/86)unmethylated, and 16.3% (14/86) borderline.In the entire cohort,there was no association between MGMT methylation status and pCR (p=0.522).Non-carboplatin cohort: 33.3% (6/18) of patients with methylated MGMT achieved pCR vs. 51.9% (28/54) of unmethylatedand 21.4% (3/14) of borderline (p=0.079).Carboplatin cohort: 52.9% (9/17) of patients with methylated MGMT achieved pCR vs. 55.2% (32/58) of unmethylatedand 76.9% (10/13) of borderline (p=0.320). In TNBC patients with methylated MGMT, the addition of carboplatin resulted in a 20% increased pCR rate (p=0.241).

Conclusion: In this study no statistically significant association between MGMT methylation andpCR was found.Patients with MGMT methylation seemed to have a lower possibility to achieve a pCR and the addition of carboplatin seemed to reverse this effect. However, a clear classification of the borderline MGMT samples and further studies in larger series of TNBC are warranted.

Citation Format: Fontanella C, Gehlhaar C, Denkert C, Schneeweiss A, Heppner B-I, Koch I, Blohmer J-U, Jackisch C, Lederer B, Fasching PA, Müller V, Untch M, Aprile G, Puglisi F, Nekljudova V, Heppner F, von Minckwitz G, Loibl S. Predictive value of O6-methylguanine-DNA methyltransferase (MGMT) promoter gene methylation in triple-negative breast cancer patients receiving carboplatin. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-55.

Intrasellar malignant peripheral nerve sheath tumor (MPNST)

Intracranial malignant peripheral nerve sheath tumors (MPNST) and intrasellar schwannomas are rare tumors. We describe a case of an intrasellar schwannoma with progression to a MPNST, a finding that, although very rare, extends the differential diagnosis of intrasellar lesions.

The peripheral benzodiazepine binding site in the brain in multiple sclerosis: quantitative in vivo imaging of microglia as a measure of disease activity

This study identifies by microautoradiography activated microglia/macrophages as the main cell type expressing the peripheral benzodiazepine binding site (PBBS) at sites of active CNS pathology. Quantitative measurements of PBBS expression in vivo obtained by PET and [(11)C](R)-PK11195 are shown to correspond to animal experimental and human post-mortem data on the distribution pattern of activated microglia in inflammatory brain disease. Film autoradiography with [(3)H](R)-PK11195, a specific ligand for the PBBS, showed minimal binding in normal control CNS, whereas maximal binding to mononuclear cells was found in multiple sclerosis plaques. However, there was also significantly increased [(3)H](R)-PK11195 binding on activated microglia outside the histopathologically defined borders of multiple sclerosis plaques and in areas, such as the cerebral central grey matter, that are not normally reported as sites of pathology in multiple sclerosis. A similar pattern of [(3)H](R)-PK11195 binding in areas containing activated microglia was seen in the CNS of animals with experimental allergic encephalomyelitis (EAE). In areas without identifiable focal pathology, immunocytochemical staining combined with high-resolution emulsion autoradiography demonstrated that the cellular source of [(3)H](R)-PK11195 binding is activated microglia, which frequently retains a ramified morphology. Furthermore, in vitro radioligand binding studies confirmed that microglial activation leads to a rise in the number of PBBS and not a change in binding affinity. Quantitative [(11)C](R)-PK11195 PET in multiple sclerosis patients demonstrated increased PBBS expression in areas of focal pathology identified by T(1)- and T(2)-weighted MRI and, importantly, also in normal-appearing anatomical structures, including cerebral central grey matter. The additional binding frequently delineated neuronal projection areas, such as the lateral geniculate bodies in patients with a history of optic neuritis. In summary, [(11)C](R)-PK11195 PET provides a cellular marker of disease activity in vivo in the human brain.

Endoscopic neurosurgery

This paper describes an ultrasound-guided, laser-assisted, and TV-controlled endoscopic technique which has been used so far in 133 patients for a variety of intracranial lesions. Following CT or MRI image reconstruction, and a decision on the placement of a 1 cm or a 2 cm burrhole, a 1 cm 5.0 mHz or 7.5 mHz intraoperative ultrasound probe is used to direct the endoscope from the burrhole to the target area. A 22.5 cm long rigid endoscope tube with an outer diameter of 6 mm with an inbuilt suction irrigation system, Neodymium Yag laser with 600 micron Quartz glass-fibre and an inlet for various microinstruments is then introduced. The attachment of a TV camera to the ocular lens allows the operator to control further surgical steps in the target area via the TV screen and thus warrants sterility in the operating field. The technique has been used for evacuation of 77 spontaneous intracerebral haematomas (lobar, putaminal, thalamic), 8 traumatic intracerebral haematomas, 13 ventricular haematomas, 8 cerebellar haematomas and 1 brainstem haematoma. Total or subtotal evacuation was achieved in 33% of intracerebral haematomas, removal of more than 50% of the clot in 55%. Twenty-four brain tumours (12 ventricular, 12 cystic cerebral or cerebellar tumours) were operated on for biopsy, evacuation of cyst, resection or removal of the cyst wall and/or laser irradiation of solid tumour or the inner cyst wall of cystic tumours. The complication rate probably related to surgery was 1.6%, morbidity 1.6%, mortality 0%. This high-tec endoscopic technique with its minimal surgical trauma and short operation time can be recommended as a low-risk alternative to conventional neurosurgical techniques.

[Local hyperthermia of malignant brain tumors]

In glioblastoma multiforme and high-grade astrocytomas the following procedure has been implemented to try and prevent recurrence: after extirpation of the tumour its bed is lined with metal powder and the patient's head is exposed to a high-frequency magnetic field every 4 weeks. As a result the temperature is raised by induction to +45 degrees C at the boundary between metal and brain tissue. This ought to be sufficient to prevent tumour recurrence. Varied results were achieved using this technique in 103 patients.

CO2 laser surgery of intramedullary spinal cord tumors

Of a total of 580 patients suffering from expanding spinal disease, 15 cases of intramedullary lesions were dealt with by the use of the CO2 laser. Sharp cutting and precisely controlled depth effect are the advantages that make the CO2 laser very useful for surgery within the spinal cord. In tumors of tough consistency the neoplastic tissue is usually sharply demarcated, in which case the CO2 laser is used for dissection along this borderline, at an output energy of 15-20 W, infocus, continuous wave (CW). In tumors of soft consistency, characterized by a more-or-less diffuse zone of invasion--eg, glioblastomas-vaporization [20 W, out-of-focus, CW] and removal by ultrasound-microsuction is recommended. This procedure should advance layer by layer until normal looking tissue is reached. In this way intramedullary tumors may be removed with minimal side effects. The postoperative course involves less pain and less edematous reaction, and the rehabilitation time is shortened compared with conventional surgical treatment. In benign neoplasms long-term results are good; malignant cases require additional x-ray treatment and chemotherapy.

The glioblastoma multiforme: a lifelong challenge to the neurosurgeon

During a period of 34 years 1316 gliomas of the brain have been treated, among them 508 glioblastomas (= 39%). In addition to the operative removal and postoperative X-ray therapy of glioblastomas various attempts have been undertaken to prevent recurrences: Intracerebral application of Cobalt60 (6 patients); locally applied antimitotic agents (76 patients); bacterial liquefaction induced by intracarotid administration of Clostridium butyricum M 55 spores ("Oncolysis", 67 patients); circumscribed heating of the extirpation cavity with metal and high-frequency electromagnetic field (85 patients); vaporization of the tumour bed with the defocussed CO2- or Neodymium-YAG-Laser beam (177 patients). Permanent cure has been attained only in single cases so that the problem does not yet seem to be definitely solved by any of these methods. However, bacterial oncolysis in combination with the periodic postoperative generation of heat locally in the excision cavity of the tumour, might justify cautious optimism about future developments.

Does acute endoscopic evacuation improve the outcome of patients with spontaneous intracerebral hemorrhage?

A new endoscopic technique is presented, which allows burr hole evacuation of intracerebral hematomas under video control. Clot removal is achieved using a suction-irrigation system built in the 6-mm-diameter endoscope; in addition, an ultrasonic morcellement device has been developed for transendoscopic application. Small bleeding vessels in the hematoma cavity can be coagulated using a 1.5 mm Neodym YAG Laser microprobe introduced through the endoscope under visual control. A randomized prospective study has been started to raise again the question of indications for the surgical treatment of intracerebral hemorrhages, comparing medical treatment with the new surgical technique.

Direct surgical attack on pontine and rhombencephalic lesions

The introduction of lasers in neurosurgery in 1976 can be considered as a major contribution to gaining access to "untouchable" areas of the brain. This immaterial instrument provides for precise cutting at low penetration depth in surrounding tissues and may carbonize, and thus remove, layers not to be touched because of their highly sensitive vicinity. From a total of 794 patients experiencing the advantages of laser surgery (1976-1984), a series of 12 children with lower brainstem tumors is presented. Intraoperative instability of vital functions was absent throughout, leaving the patients without deterioration of their initial neurological condition. Given appropriate handling and adequate experience, the laser is a singularly helpful surgical tool for gaining access to areas hitherto barred to surgery.

CO2-Laser in neurosurgery

New technical tools in surgery are only beneficial if they offer real improvements compared to the traditional techniques or if they open absolute new indications in surgery. Therefore we have tried to find absolute indications for the use of the indifferent laser system. Due to the specific wavelength the CO2-Laser is entirely absorbed at the surface. This specific performance allows one to use the CO2-Laser as the most precise cutting and as a completely new vaporizing instrument. It has become an irreplaceable tool in surgery of central lesions and brain stem tumours and also for spinal cord tumours. In addition the CO2-Laser is adaptable to the operating microscope. A gain of the same importance in the meantime is the Nd-YAG Laser, which works specially for coagulation, volume coagulation and endoscopic use. It is certain that laser surgery will evolve for beyond our imagination.

Flow patterns at the site of extracranial to intracranial end to side anastomosis. An experimental rheological study

Flow property measurements were performed in a plexiglass model of six various types of end-to-side anastomosis (as clinically shown in extracranial to intracranial arterial bypass surgery). Three anastomoses were made without, another three anastomoses with a ringshaped stenosis restricting the lumen to between 25 and 46% of the cross-section as it occurs clinically by formation of thrombi out of the striching canals. A rectangular type and two of 45 degree oblique types--one directed centrally and one directed peripherally--were tested. Pressure head losses at the site of anastomosis were measured under various circumstances of different anastomoses and different flow speeds along the proximal portion of the middle cerebral artery and the superficial temporal artery. Flow resistance values originated by the different types of anastomoses were expressed in terms of additional recipient vessel length. Differences between different types of anastomoses with and without stenosis were very small and under no circumstances exceeded the equivalent of lengthening the recipient vessel by 2 cm. Theoretically, the optimal type of anastomosis is the oblique and centrally directed version; the worst type is the rectangular form. Practically, however, such differences are not relevant. The explanation for such unexpectedly small differences can rheologically be given by considering the dominating role of blood viscosity under the given circumstances, other variables such as short stenosis and angling of flow playing a secondary role.

New technologies to combat malignant tumours of the brain

1. The primary problem in an effective treatment of a glioblastoma is the prevention of a recurrence. 2. For that purpose were the following therapeutical procedures undertaken: (a) Temporary implantation of radio cobalt in the brain itself (1957): (b) Clostridium butyricum M 55 was used to render the centre of the tumour fluid (1967): (c) Podophyllin was used to destroy the border of the tumour (1980); (d) The CO2 Laser beam (1975); (e) The electromagnetic heat induction deep in the brain (1973-1978). 3. In order to make the operation and postoperative phase safer for the patient, the following precautions were drawn upon or employed: (a) Hyperbaric oxygenisation in the pressure chamber (1971); (b) The anti-G-suit (1974); (c) the computer controlled automatic infusion pump (1980), and (d) the telemetric measurement of intra-cranial pressure (1975). 4. Apart from the pressure chamber, the mentioned devices were all supervised and developed in the department of the author. 5. The first successful means in the prevention of the recurrence of a glioblastoma multiform seems to be the telethermic method mentioned in 2 (e) above.

Diagnosis and treatment of middle fossa arachnoid cysts and subdural hematomas

Nine cases with temporal fossa arachnoid cysts were diagnosed by computerized tomography (CT). Five patients also had subdural hematomas, three of them following head trauma. When the hematoma was chronic and of equal hypodensity with the cyst, a clear-cut differentiation was not possible from the CT scan. The presence of a subdural hematoma could only be suggested by thickened arachnoid structures crossing the hypodense area, indicating the wall between cyst and hematoma. The cyst could often be diagnosed by bulging of the skull bone and a temporal lobe defect. Differences in density between cyst and hematoma, such as in subacute subdural hematoma, delineated both entities. Typical examples are demonstrated. Treatment consisted of evacuation of the hematoma and excision of the cyst in all cases.

[Natural history and operative treatment of intracranial aneurysms after subarachnoid haemorrhage (author's transl)]

This report presents an evaluation of prognosis in 227 patients with subarachnoid haemorrhage caused by intracranial aneurysm, comparing operative treatment in 118 patients with conservative treatment in 109. In all operable cases, the prognosis following early surgery was better than that of conservative treatment. Statistical comparison of patient groups according to the clinical condition allowed the formation of guidelines for the optimal timing of surgery: patients in good clinical condition should be operated on at the earliest possible moment. The overall mortality with such a policy is lower than with a waiting policy, since the majority of recurrences occurred within 2 weeks. Patients with disturbed consciousness and neurological deficit are best operated on either within 24 hours or following stabilization or improvement of the clinical picture -- mostly after 2 weeks. The risk of rebleeding is much lower in these cases, which justifies awaiting optimum clinical conditions. Surgery on comatose patients is contraindicated.

Predicting lethal outcome after severe head injury -- a computer-assisted analysis of neurological symptoms and laboratory values

A total number of 58 parameters (laboratory values, neurological symptoms, and vegetative parameters) were evaluated in 150 patients during the first seven days after severe head injury. The patients were divided into two groups, "survivors" and "non-survivors". Eight easily evaluable routine parameters with the most significant differences between the two groups of patients were used for statistical evaluation of a "no survival chance score". These highly indicative parameters are serum osmolarity and urea, blood glucose, total bilirubin, motor reaction to stimuli, body temperature, respiratory activity, and pupil reaction. A "low survival chance limit" was evaluated from each of these parameters by computer analysis. None of the patients in the series survived when three or more of these eight parameters had climbed beyond the limit. So far, the system is able to predict "no survival chances" in 50.8% of the non-survivors some six days prior to death; 80% of these predictions could be made by the fourth day after injury.

Variations of pial arteriolar diameter, arterial blood pressure and arterial blood density in the cat

Feline pial arteriolar diameters (CVD, cerebral vessel diameter), mean arterial blood pressure and blood density were recorded continuously in order to examine the relation between rhythmic diameter variations and oscillations of blood pressure and density. Under constant arterial pressure, blood density and CVD oscillations of 2-6/min were recorded using a photometric technique. Furthermore, pressure and density variations were induced by bleeding and reinfusion of blood, to observe their influence on CVD. The latter over a period of time become synchronized to parallel variations of pressure and density during hemorrhagic hypotension. This observance was noted after an initial lag phase.

Medical versus surgical treatment of patients with cerebrovascular insufficiency. A retrospective comparative study

Report on a series of patients suffering from cerebrovascular insufficiency caused by stenosis and/or occlusion of one or several major cerebral vessels. The patients were divided in two groups, one being medically treated with anticoagulants, the other operated on either a carotid artery thrombosis by thromboendarterectomy or occlusion treated with an extracranial-intracranial arterial bypass. Results after a follow-up period of 1-3 years are compared and discussed in view of the recent literature.

[Psychosurgery today (author's transl)]

After discussion of the historical and neurophysiological bases of psychosurgery a report on personal experience in different indications is given. Finally, the present degree of informedness of doctors and the media on psychosurgery is discussed.

Proteolytic enzyme activity in patients with severe head injury and the effect of a proteinase inhibitor

A study was performed to detect the inhibitory effect of intravenously administered aprotinin (Trasylol) on brain and CSF protease activity in 25 patients with severe head injury. The data presented include measurements of CSF protease activity, alpha-1-antitrypsin, alpha-2-macroglobulin, haptoglobulin, polyacrylamidgel-electrophoresis pattern, total protein and hemoglobin content. The results indicate that increased protease activity is present and that this induces autolytic processes which can be inhibited by aprotinin treatment. The survival rate was higher after aprotinin treatment. Total CSF protein content was significantly higher in nonsurvivors than in survivors.

The operative approach to lipomas of the corpus callosum

Survey on the incidence, pathology and the surgical attempts undertaken so far in lipomas of corpus callosum. Report of a case of radical removal with the aid of CO2-Laser beam followed by complete recovery in a 21-year-old woman.

[Therapy of traumatic brain edema with spironolactone (author's transl)]

In 30 patients with severe brain injury a double-blind study was performed. The effectiveness of the aldosterone-antagonist Aldactone pro injectione was examined in therapy of traumatic brain edema. The results indicate elimination of sodium and water from brain cells and white matter. Concomitantly faster improvement of state of consciousness was observed.

The liquefaction (oncolysis) of malignant gliomas by a non pathogenic Clostridium

Vascular glioblastomas become liquefied when contaminated with spores of the non-pathogenic Clostridium butyricum M 55. The spores are administered by intracarotid injection. The oncolysis is complete one week after injection. The glioblastoma is converted into a brain abscess which is then operated on appropriately. Forty nine patients have been treated in this manner. The rate of recurrence, however, remained uninfluenced.

[Continuous telemetric recording of intracranial pressure]

A report is given on the development of a telemetric system for continuous recording of intracranial pressure, using an external energy source. The pressure transducer, called Teleceptor, is placed in the subdural space through a burr hole. The resonance frequencies of the transmitter and receiver circuits in the implanted transducer are influenced by a pressure-sensitive membrane in such a way that pressure variations result in resonance point displacement and energy transfer reduction. The necessary tuning of the transmitter frequency to maximum energy transfer is in direct proportion to the magnitude of pressure modification.

Telemetry of intracranial pressure

A new technique is described for telemetric measurement of intracranial pressure in man using an external energy source and a small pressure transducer, called a TELECEPTOR, implanted in the skull. The method presents advantages, especially for long term recordings.

[Telemetry of intracranial pressure (preliminary report) (author's transl)]

The authors report the application of a telemetric system for continuous recording of intracranial pressure.