Acoustic Neuroma

An Acoustic Neuroma also known as Vestibular Schwannoma is a slow growing tumor that develops on the cranial nerve that connects the ear to the brain. Cranial nerves are those nerves that arise directly from the brain. An acoustic Neuroma is a benign (non-cancerous) growth that forms on the sheath covering of the eighth cranial nerve called vestibulocochlear nerve. The eighth cranial nerve has two divisions, the vestibular nerve that controls the balance and the cochlear nerve that takes care of the hearing function. These two nerves are lined by Schwann cells and acoustic neuroma occurs when there is a large production of Schwann cells forming into a tumor.

Schwannoma that occurs in other peripheral nerves are largely benign unless it is a Neurofibrosarcoma - a malignant form of cancer.

Symptoms of acoustic neuroma

• The early signs of the condition include hearing impairment in the affected ear and the balancing difficulties. Since nerves of eighth cranial are responsible for hearing and balance, the problems related to these functions are the first to surface in the initial stages of acoustic neuroma. Patient may also feel heavy or fullness in the affected ear. Hearing loss either progressively or suddenly in the affected ear is the most obvious symptom of acoustic neuroma.
  
  
• Tinnitus is an ear condition where the patient experiences constant buzzing or ringing sounds in the ear. Though Tinnitus is a common symptom associated with acoustic neuroma, not all the cases will develop this symptom. It is also to be noted that all those who experience tinnitus do not have tumor growing on the ear nerve.
  
  
• Vertigo and unsteadiness is the common symptom with acoustic neuroma.
  
  
• When the tumor becomes large, it may compress the brainstem and result in headaches.
  
  
• Though not very common, acoustic neuroma may cause facial numbness and paralysis. Large tumors may compress the fifth cranial nerve (facial nerve) called trigeminal nerve, resulting in facial numbness, pain and facial paralysis.
  

Diagnosis and Treatment

Diagnosing acoustic neuroma is a daunting task as the symptoms explained above are associated with many other medical conditions and it could easily be mistaken for middle ear disorder. Once suspected, doctor will advise MRI, the only test conducted to prove the presence of acoustic neuroma. Few of the hearing (audiometry) and balancing (nystagmus) tests are also conducted to assess the hearing and balance functions.

There are three options available to treat acoustic neuroma. The choice of treatment depends upon the size of the tumor, it's location and patient's age and fitness.

Micro surgery involves removing the tumor either partially or totally through surgery. Partial removal is considered when the tumor is large and the total removal leads to the damage of the facial nerve. In case of partial removal, the patient has to undergo repeated MRI scans at regular intervals to ensure that tumor is not growing again. When the tumor does not pose a risk to the adjacent nerves, one can opt for a total removal of the tumor. Though surgery is the most preferred choice of addressing the acoustic neuroma, utmost care should be taken to preserve the hearing function and the facial nerve of the patient.

Radiation is the second best option for treating acoustic neuroma. Radiation is a non-invasive treatment that uses precisely focused, narrow beams of radiation to shrink the acoustic neuroma. Currently, radiation is either delivered as single fraction stereotactic radio surgery (SRS) or as multi-session fractionated stereotactic radiotherapy (FSR). These techniques deliver high doses of radiation to the tumor and also ensure that surrounding areas and organs like brain, skull and skin receive minimum or no radiation.

SRS involves a single dose of radiation wherein multitude of radiation beams are delivered to the tumor in one single sitting. Patient need not return for treatment except for a follow up. Though SRS is very effective, it may not preserve the hearing function in most cases.

In FSR, smaller doses of radiation are given every day, over a period of three to four weeks. FSR method has better chances of preserving the hearing function compared to SRS method.

Sometimes doctors may just ask the patient to wait and watch than begin a treatment for acoustic neuroma. Holding back the treatment is most ideal when the tumor is not producing any symptoms and is small in size (less than 2 cm). Acoustic Neuroma does not require any medical intervention if the tumor is not growing rapidly. The growth of the tumor is normally observed by going for repeated MRI on a regular basis for few years. Wait and watch approach also best suits older patients with small tumors that have stopped growing. They will only be monitored periodically with the help of diagnostic tests.

Brain Cancer

Malignant tumors in the brain are the consequence of abnormal growth of cells in the brain. Brain cancers can be primary, arising from primary brain cells, or from other brain components. Metastatic brain cancer starts elsewhere in the body and spreads to the brain. About 25% of tumors elsewhere in the body metastasize to the brain. The most common cancers that metastize to the brain are lung cancer, breast cancer, colon cancer and melanoma. The majority of brain metastases are located in the cerebral hemispheres and then in the cerebellum. Very few occur in the brain stem.

Causes/ risk factors for brain cancer

• Any radiation to the head
  
• Hereditary
  
• HIV infection
  
• Smoking
  
• Toxins found in the environment such as chemicals in oil refinery, rubber industry chemicals etc)
  

Symptoms of Brain Cancer

• Severe headache in the morning.
  
• Nausea and vomiting, especially early in the mornings.
  
• Some changes/problems while talking, listening or seeing.
  
• Problems while walking.
  
• Memory problems or lack of alertness.
  
• Twitching of muscles or seizures.
  
• Numbness in the arms or legs.
  
• General weakness
  
• Clumsiness
  
• Gradual changes in intellectual and emotional capacity.
  

These symptoms may be very gradual and therefore overlooked by the patient. Occasionally however, these symptoms may appear more rapidly.

Who is at risk for brain cancer ?

Persons with the following conditions are at more risk for developing cancer of the brain.

• Frequent exposure to radiation
  
• Age
  
• Exposure to pesticides, herbicides and fertilizer
  
• Workers occupied in petroleum, plastic, rubber and textile industries.
  
• Exposure to electromagnetic fields
  
• Genetic disorders
  

Diagnosis of Brain Cancer

MRI has higher sensitivity for detecting the presence and characteristics of a tumor. In case, the CT or MRI indicates the presence of a brain tumor, the patient will be referred to a neurosurgeon or to a neuro oncologist. The next step in diagnosis is to confirm cancer in the brain. A biopsy is taken to identify the type of tumor and the grade of the tumor. This is done by a surgical procedure called craniotomy. The skull is opened with the intention of removing the whole tumor if possible. A biopsy is taken from the tumor. In some cases, if the exact location of the tumor is detected, by using a CT or MRI scan, a biopsy is taken without opening the skull. This technique is stereotaxis, where a needle is used to collect the biopsy. A pathologist examines the biopsy under a microscope and diagnoses the disease.

Brain cancer treatment

Treatment for brain cancer is based on the patient's age, and general health status, size, location and type and grade of the tumor. In most cases of brain cancer, surgery, radiation and chemotherapy are the preferred treatment. As treatment protocols of brain cancer are highly complex, most treatment plans will involve several consultations and sittings with the neurosurgeon, oncologist, radiation oncologist and healthcare provider.

Most people with brain cancer undergo surgery to assign and grade the tumor and then remove the tumor or take a sample to identify the type and grade. In some cases, a benign tumor can be cured by surgical intervention and removal of tumor.

Stereotactic radio surgery, a knife less technique that can destroy a brain tumor without opening the skull can be adopted. With a CT or MRI, the exact location is pinpointed and with high energy radiation beams the tumor from different angles is destroyed. Knife less procedure has fewer complications and the recovery time is shorter. The disadvantage is the lack of tissue available to send to a pathologist for diagnosis of brain swelling.

Radiation can be administered externally or internally. External radiation travels through skin and the skull, healthy brain tissue and other tissues to get to the tumor. Internal radiation uses a tiny radioactive capsule placed inside the tumor itself. The radiation emitted from the capsule destroys the tumor.

Chemotherapy drugs may be administered by mouth or through an IV line. Chemotherapy is usually administered in cycles, each cycle consisting of a short period of intensive treatment followed by a period of rest and recovery. The side effects of chemotherapy include nausea, vomiting, mouth sores, loss of appetite, loss of hair among others. New therapies with the use of nanotechnology for cancer are being developed and are promising. Regular follow up is essential after treatment of brain cancer. Such checkups would include physical and neurologic exams, and occasional CT and/or MRI.

Bone cancer

Bone tumor is an abnormal growth of cells within a bone. Bone tumors may be malignant or benign. Though the causes of bone tumors are unknown, some possible causes include hereditary or genetic defects, radiation and injury. In most cases, no specific cause is found. Osteochondromas is a most common non cancerous bone tumor which occurs in people between ages ten and twenty. While primary bone cancers start from bones, secondary or metastatic bone tumors start in another part of the body such as breast, kidney, lung, prostate and thyroid and spread. These forms of cancer usually affect older people.

Symptoms of bone cancer

Some common bone cancer symptoms include:

• Bone fracture or fracture from slight injury or trauma.
  
• The most common symptom of bone cancer is pain. Though mild initially, bone pain gradually becomes intense and tends to worsen at night.
  
• A mass or lump may be felt on the bone or the tissues surrounding the bone. This is common with fibrosarcoma.
  
• Bones become weakened by tumor and may lead to a fracture. This can occur with both benign and malignant tumors.
  
• Mass swelling at the tumor site which may be occasionally found.
  
• Pain, numbness and tingling in the extremities can be found if tumor is compressed and this can affect the blood flow to the extremities.
  
• Fever, chills and night sweats can occur though these are less common signs.
  
• Weight loss can occur in some cases.
  

Diagnosis of bone cancer

After taking into account the complete medical history and performing a physical examination, the following diagnostic tests would be done.

• Alkaline phosphatase blood test.
  
• CT scan can give a cross sectional picture of the bones and additional information on the size and location of the tumor.
  
• MRI of the bone and surrounding tissues can provide cross sectional imaging of the body and better details of soft tissues, including muscles, tendons, ligaments, nerves and blood vessels.
  
• X ray of the bone and surrounding tissues.
  
• A bone scan is taken on the entire body and is not specific for any type of tumor.
  
• Bone biopsy: When the tumor is identified, the doctor may then obtain a biopsy sample of the tumor. This involves taking a small sample of the tumor and examining it in the laboratory by a pathologist. This biopsy can be obtained through a small needle or through a small incision.
  

Treatment of bone cancer

There are many treatment options for bone cancer depending upon the type of bone cancer and the location of the cancer. It also depends on whether or not the cancer has spread from the bone to surrounding tissues. Treatment options include surgery, chemotherapy and radiation therapy. These can be used individually or in combination with each other.

Although some benign bone tumors tend to go away on their own and hence do not require treatment, close monitoring is essential to see if the tumor shrinks or grows. In case of malignant tumors, surgery would become essential. The goal of surgery is to remove the entire tumor and its surrounding area or normal bone. A pathologist examines the tumor once removed to determine if there is normal bone completely surrounding the tumor. In case the cancer is left behind, chances are it can continue to grow and spread requiring further treatment.

Depending upon the size/amount of bone removed, the surgeon will replace either by bone cement or bone graft from another place in the body or from the bone bank. For larger areas, larger grafts from the bone bank or metal implants are done. Historically, amputation was the technique used to remove bone cancer. However, new techniques adopted have significantly decreased the need for amputation. Treatment for cancers that spread from other parts of the body would depend upon where the cancer started.