Made by DATEXIS (Data Science and Text-based Information Systems) at Beuth University of Applied Sciences Berlin
Deep Learning Technology: Sebastian Arnold, Betty van Aken, Paul Grundmann, Felix A. Gers and Alexander Löser. Learning Contextualized Document Representations for Healthcare Answer Retrieval. The Web Conference 2020 (WWW'20)
Funded by The Federal Ministry for Economic Affairs and Energy; Grant: 01MD19013D, Smart-MD Project, Digital Technologies
Treatment typically consists of radiotherapy and steroids for palliation of symptoms. Radiotherapy may result in minimally extended survival time. Prognosis is very poor, with only 37% of treated patients surviving one year or more. Topotecan has been studied in the treatment of brainstem glioma, otherwise, chemotherapy is probably ineffective, though further study is needed.
Acoustic neuromas are managed by either surgery, radiation therapy, or observation with regular MRI scanning. With treatment, the likelihood of hearing preservation varies inversely with the size of the tumor; for large tumors, preservation of hearing is rare. Because acoustic neurmas, meningiomas and most other CPA tumors are benign, slow growing or non-growing, and non-invasive, observation is a viable management option.
The objective of irradiation is to halt the growth of the acoustic neuroma tumour, it does not excise it from the body, as the term 'radiosurgery' or 'gammaknife' implies. Radiosurgery is only suitable for small to medum size tumors.
Surgical removal of tumors is an option, however the risks involved should be assessed first. With regard to OPG (optic pathway gliomas), the preferred treatment is chemotherapy. However, radiotherapy isn't recommended in children who present with this disorder. It is recommended that children diagnosed with NF1 at an early age have an examination each year, which allows any potential growths or changes related to the disorder to be monitored.
A 2009 clinical trial at Massachusetts General Hospital used the cancer drug Bevacizumab (commercial name: Avastin) to treat 10 patients with neurofibromatosis type II. The result was published in "The New England Journal of Medicine". Of the ten patients treated with bevacizumab, tumours shrank in 9 of them, with the median best response rate of 26%. Hearing improved in some of the patients, but improvements were not strongly correlated with tumour shrinkage. Bevacizumab works by cutting the blood supply to the tumours and thus depriving them of their growth vector. Side effects during the study included alanine aminotransferase, proteinuria, and hypertension (elevated blood pressure) among others. A separate trial, published in "The Neuro-oncology Journal", show 40% tumour reduction in the two patients with NF2, along with significant hearing improvement.
Overall the researchers believed that bevacizumab showed clinically significant effects on NF-2 patients. However, more research is needed before the full effects of bevacizumab can be established in NF-2 patients.
A schwannoma is a usually-benign nerve sheath tumor composed of Schwann cells, which normally produce the insulating myelin sheath covering peripheral nerves.
A vestibular schwannoma (VS) is a benign primary intracranial tumor of the myelin-forming cells of the vestibulocochlear nerve (8th cranial nerve). A type of schwannoma, this tumor arises from the Schwann cells responsible for the myelin sheath that helps keep peripheral nerves insulated. Although it is also called an acoustic neuroma, this a misnomer for two reasons. First, the tumor usually arises from the vestibular division of the vestibulocochlear nerve, rather than the cochlear division. Second, it is derived from the Schwann cells of the associated nerve, rather than the actual neurons (neuromas).
Approximately 2,000 to 3,000 cases are diagnosed each year in the United States (6 to 9 per million persons). Comprehensive studies from Denmark published in 2012 showed an annual incidence of 19-23 per million from 2002 to 2008, over the last 30 years the reported incidence have been increasing, until the last decade in which an approximation of the true incidence may have been found. Most recent publications suggest that the incidence of vestibular schwannomas have been rising because of advances in MRI scanning.
Most cases are diagnosed in people between the ages of 30 and 60, and men and women appear to be affected equally. Most vestibular schwannomas occur spontaneously in those without a family history. One confirmed risk factor is a rare genetic mutation called NF2.
The primary symptoms of vestibular schwannoma are unexplained progressive unilateral hearing loss and tinnitus, and vestibular (disequilibrium) symptoms. Treatment of the condition is by surgery or radiation, and often results in substantial or complete hearing loss in the affected ear. Observation (non-treatment) over time also usually results in hearing loss in the affected ear.
There are three treatment options available to a patient. These options are observation, microsurgical removal and radiation (radiosurgery or radiotherapy). Determining which treatment to choose involves consideration of many factors including the size of the tumor, its location, the patient's age, physical health and current symptoms. About 25% of all acoustic neuromas are treated with medical management consisting of a periodic monitoring of the patient's neurological status, serial imaging studies, and the use of hearing aids when appropriate.
One of the last great obstacles in the management of acoustic neuromas is hearing preservation and/or rehabilitation after hearing loss. Hearing loss is both a symptom and concommitant risk, regardless of the treatment option chosen.
Treatment does not restore hearing already lost, though there are a few rare cases of hearing recovery reported.
A diagnosis of NF2 related bilateral acoustic neuromas creates the possibility of complete deafness if the tumors are left to grow unchecked. Preventing or treating the complete deafness that may befall individuals with NF2 requires complex decision making. The trend at most academic U.S. medical centers is to recommend treatment for the smallest tumor which has the best chance of preserving hearing. If this goal is successful, then treatment can also be offered for the remaining tumor. If hearing is not preserved at the initial treatment, then usually the second tumor, in the only-hearing ear, is just observed. If it shows continued growth and becomes life-threatening, or if the hearing is lost over time as the tumor grows, then treatment is undertaken. This strategy has the highest chance of preserving hearing for the longest time possible.
There are several different surgical techniques for the removal of acoustic neuroma. The choice of approach is determined by size of the tumour, hearing capability, and general clinical condition of the patient.
- The retrosigmoid approach offers some opportunity for the retention of hearing.
- The translabyrinthine approach will sacrifice hearing on that side, but will usually spare the facial nerve. Post-operative cerebrospinal fluid leaks are more common.
- The middle fossa approach is preferred for small tumours, and offers the highest probability of retention of hearing and vestibular function.
- Less invasive endoscopic techniques have been done outside of the United States for some time. Recovery times are reported to be faster. However, this technique is not yet mainstream among surgeons in the US.
Larger tumors can be treated by either the translabyrinthine approach or the retrosigmoid approach, depending upon the experience of the surgical team. With large tumors, the chance of hearing preservation is small with any approach. When hearing is already poor, the translabyrinthine approach may be used for even small tumors. Small, lateralized tumours in patients with good hearing should have the middle fossa approach. When the location of the tumour is more medial a retrosigmoid approach may be better.
Auditory canal decompression is another surgical technique that can prolong usable hearing when a vestibular schwannoma has grown too large to remove without damage to the cochlear nerve. In the IAC (internal auditory canal) decompression, a middle fossa approach is employed to expose the bony roof of the IAC without any attempt to remove the tumor. The bone overlying the acoustic nerve is removed, allowing the tumour to expand upward into the middle cranial fossa. In this way, pressure on the cochlear nerve is relieved, reducing the risk of further hearing loss from direct compression or obstruction of vascular supply to the nerve.
Radiosurgery is a conservative alternative to cranial base or other intracranial surgery. With conformal radiosurgical techniques, therapeutic radiation focused on the tumour, sparing exposure to surrounding normal tissues. Although radiosurgery can seldom completely destroy a tumor, it can often arrest its growth or reduce its size. While radiation is less immediately damaging than conventional surgery, it incurs a higher risk of subsequent malignant change in the irradiated tissues, and this risk in higher in NF2 than in sporadic (non-NF2) lesions.
The preferred treatment for esthesioneuroblastoma is surgery followed by radiotherapy to prevent reoccurrence of the tumor.
Systemic (intravenous or oral) chemotherapy and intrathecal chemotherapy: Intrathecal therapy is when injection is done directly to the spinal cord into the sub-arachnoid space to avoid the Blood-Brain-Barrier (BBB) and gain direct access to the CSF. Intrathecal Therapy is preferred since intravenous chemotherapy do not penetrate the BBB. The most common chemicals used are liposomal cytarabine (DepoCyte) and intrathecal methotrexate (MTX).
In combination, intrathecal chemotherapy most often comprises methotrexate, cytarabine, thiotepa and steroids. Ventriculoperitoneal shunts may also be applied with chemotherapy to avoid invasive surgery to gain access to the CSF.
An example of treatment:
Intrathecal MTX injection at a dose of 15 mg/day for 5 days every other week with hydrocortisone acetate injecting IT on day one to prevent arachnoiditis, the inflammation of the arachnoid. MTX administration is continued until neurological progression or relapse occurred. Systemic chemotherapy, radiotherapy, and surgery are performed depending on the need of the patient.
Risks of treatments:
Both Chemotherapy and Radiotherapy are harmful to the body and most definitely the brain. Caution must be utilized in treating patients with NM. Another factor that makes treatment difficult is that there is no suitable method to evaluate the disease progression.
A brain stem tumor is a tumor in the part of the brain that connects to the spinal cord (the brain stem).
Schwannomas are homogeneous tumors, consisting only of Schwann cells. The tumor cells always stay on the outside of the nerve, but the tumor itself may either push the nerve aside and/or up against a bony structure (thereby possibly causing damage). Schwannomas are relatively slow-growing. For reasons not yet understood, schwannomas are mostly benign and less than 1% become malignant, degenerating into a form of cancer known as neurofibrosarcoma. These masses are generally contained within a capsule, and so surgical removal is often successful.
Schwannomas can be associated with neurofibromatosis type II, which may be due to a loss-of-function mutation in the protein merlin. They are universally S-100 positive, which is a marker for cells of neural crest cell origin.
Schwannomas of the head and neck are a fairly common occurrence and can be found incidentally in 3–4% of patients at autopsy. Most common of these is a vestibular schwannoma, a tumor of the vestibulocochlear nerve that may lead to tinnitus and hearing loss on the affected side. Outside the cranial nerves, schwannomas may present on the flexor surfaces of the limbs. Rare occurrences of these tumors in the penis have been documented in the literature.
Verocay bodies are seen histologically in schwannomas.
There is no standard treatment that has been established for NM thus treatments are almost always palliative.
Radiotherapy:
This method is used mostly for focal type of NM due to the nature of damage and success rate associated with the treatment. Radiotherapy targets and tumor and destroys the collective tissues of cancerous cells.
Several surgical approaches have been described, but post-excision recurrence rates have remained relatively high. Studies suggest better results with a bilateral approach. For cases with cribriform plate involvement, tumors are resected bilaterally using a transfacial and craniotomy approach. In a research study, the craniofacial approach decreased reoccurrence of esthesioneuroblastoma by 20%. Craniofacial resection can help preserve the optic nerves and brain while removing the cribriform plate, olfactory bulb, dura surrounding the bulb and even the orbital periosteum.
In most cases, symptoms of NF1 are mild, and individuals live normal and productive lives. In some cases, however, NF1 can be severely debilitating and may cause cosmetic and psychological issues. The course of NF2 varies greatly among individuals. In some cases of NF2, the damage to nearby vital structures, such as other cranial nerves and the brain stem, can be life-threatening. Most individuals with schwannomatosis have significant pain. In some extreme cases the pain will be severe and disabling.
The main treatment modalities are surgery, embolization and radiotherapy.
For recurrent high-grade glioblastoma, recent studies have taken advantage of angiogenic blockers such as bevacizumab in combination with conventional chemotherapy, with encouraging results.
A 2017 meta-analysis compared surgical resection versus biopsy as the initial surgical management option for a person with a low-grade glioma. Results show the evidence is insufficient to make a reliable decision. The relative effectiveness of surgical resection compared to biopsy for people with malignant glioma (high-grade) is unknown.
For high-grade gliomas, a 2003 meta-analysis compared radiotherapy with radiotherapy and chemotherapy. It showed a small but clear improvement from using chemotherapy with radiotherapy.
Temozolomide is effective for treating Glioblastoma Multiforme (GBM) compared to radiotherapy alone. A 2013 meta-analysis showed that Temozolomide prolongs survival and delays progression, but is associated with an increase in side effects such as blood complications, fatigue, and infection. For people with recurrent GBM, when comparing temozolomide with chemotherapy, there may be an improvement in the time-to-progression and the person's quality of life, but no improvement in overall survival, with temozolomide treatment.
A mutational analysis of 23 initial-low grade gliomas and recurrent tumors from the same patients has challenged the benefits and usage of Temozolomide. The study showed that when lower grade brain tumors of patients are removed and patients are further treated with Temozolomide, 6 out of 10 times the recurrent tumors were more aggressive and acquired alternative and more mutations. As one of the last authors, Costello, stated "They had a 20- to 50-fold increase in the number of mutations. A patient who received surgery alone who might have had 50 mutations in the initial tumor and 60 in the recurrence. But patients who received TMZ might have 2,000 mutations in the recurrence." Further, new mutations were verified to carry known signatures of Temozolomide induced mutations. The research suggests that Temozolomide for the treatment of certain brain tumors should be thoroughly thought. Unjudicious usage of Temozolomide might lower the prognosis of the patients further, or increase their burden. Further understanding of the mechanisms of Temozolomide induced mutations and novel combination approaches could be promising.
A paraganglioma is a rare neuroendocrine neoplasm that may develop at various body sites (including the head, neck, thorax and abdomen). Unlike other types of cancer, there is no test that determines benign from malignant tumors; long-term followup is therefore recommended for all individuals with paraganglioma. Approximately 50% of patients with recurrent disease experience distant metastasis. The five-year survival in the setting of metastatic disease is 40% to 45%.
A variety of surgeries have been performed including microvascular decompression (MVD) of the fifth, ninth, and tenth nerves; as well as partial cutting of the nervus intermedius, geniculate ganglion, chorda tympani and/or the ninth and tenth cranial nerves.
A trial of the anticonvulsant drug carbamazepine is common for patients diagnosed with GN. For patients who do not tolerate or respond to carbamazepine, alternative drugs include oxcarbazepine, gabapentin, phenytoin, lamotrigine, and baclofen. In addition, tricyclics (e.g., amitriptyline) and pregabalin are useful in other types of neuropathic pain.
A lateral pontine syndrome is a lesion which is similar to the lateral medullary syndrome, but because it occurs in the pons, it also involves the cranial nerve nuclei of the pons.
Damage to the following areas produces symptoms (from medial to lateral):
Nasopharyngeal carcinoma can be treated by surgery, by chemotherapy, or by radiotherapy. The expression of EBV latent proteins within undifferentiated nasopharyngeal carcinoma can be potentially exploited for immune-based therapies.