Diagnosing Acoustic Neuroma

Q:  I have never written a medical letter before, but after reading the response you gave a patient with an Acoustic Neuroma, I feel compelled to do so.

I was diagnosed with an Acoustic Neuroma and had surgery performed in 1991. In my research about this condition, I have come across many articles that rebut your statements.

Although an acoustic neuroma tumor is non-cancerous, and yes, no one will die of cancer from this type of tumor; it does grow, albeit slowly, and will invade the cranial cavity. It will encompass several nerves, finally pressing upon the brain stem to create severe nerve problems and cause eventual death to the patient. No one should take an acoustic neuroma lightly.

My tumor had been misdiagnosed for 8 years prior to my surgery. At the time of surgery I was told it had been growing for about 12 years. After the surgery I was left with partial facial paralysis, damage to the 7th, 5th and 8th nerves, and a total loss of hearing on the afflicted side. Had this tumor been diagnosed earlier, the severity of the aftermath would have been considerably different. The early diagnosis and treatment of this condition is vital to the outcome of the surgery on the patient. There are many, many doctors, neurologists and neurosurgeons, many of whom are your colleagues at the Medical College of Wisconsin, who can give you the most up-to-date information on the diagnosis and treatment of the Acoustic Neuroma patient. I found out that this disease is so common that there is a national association devoted to the enlightenment of the medical community regarding the diagnosis and treatment of Acoustic Neuroma and to the support of its members through various handouts and group sessions. The local Southeastern Wisconsin Association has been a lifesaver for me during the very stressful diagnosis, surgery and post-operative treatment.

Could you please correct your misleading information regarding Acoustic Neuroma and its treatment in a future column? Please urge any patient to see an Otolaryngologist (ENT specialist) immediately.

A:  You're right - I should have been much more adamant about the reader seeking help sooner. Jean J Palasz, the president of the Acoustic Neuroma Association of Wisconsin, was also kind enough to take the time to write and urge more clarification about acoustic neuroma.

Dr. Thomas Haberkamp, former Interim Chair of the Department of Otolaryngology at the Medical College of Wisconsin, told me that Froedtert Hospital has one of the largest centers in the state and region for treatment of acoustic neuromas (AN), with hundreds of tumors diagnosed and treated. Although he has never personally seen a death from an untreated AN, the tumor can be life-threatening because of pressure on the brainstem. The risks of complications from the tumor and from all forms of treatment are directly proportional to the tumor size, so early diagnosis and treatment are considered paramount. He confirmed that 80% of ANs are very slow growing (less than 1 mm per year), so it may take a decade for this tumor to change in size. Another 20% of tumors grow much faster (about 1 cm per year) and these tumors have great potential for serious complications, especially in a young person.

After diagnosis there are three options:

1. Observation. This is a viable option if the tumor size is small and is limited to the inner ear and if the patient has no acute symptoms. Observation should be the initial treatment, particularly if the patient is elderly or has serious medical problems. Periodic imaging of the brain is done to follow tumor growth. In some series, about one-half of patients under observation eventually require further treatment, so a coordinated plan of treatment is important.

2. Radiation. There are several ways of performing radiation for these tumors with the more modern techniques carrying about a 90% success rate. Follow-up is important because 5-10% of the tumors might continue to grow after radiation or at some time in the future. Radiation is also associated with risk of further hearing loss in about one-half of patients and with a chance of facial weakness and numbness in about 10% of patients. Once again the exact percentages vary with the size of tumor.

3. Surgery. Over 90% of ANs can be removed totally. Since the tumor occurs at the interface of the inner ear and brain, nowadays the surgery is usually best done by a team including an otologist and a neurosurgeon. The procedure can take up to 15 hours and one of the more common complications is facial paralysis. In very small tumors of less than 1 cm, 90% of patients will not have any long-term facial nerve damage. However, with large tumors over 3 cm, about 40-50% of patients may have facial weakness on the side of the tumor. Finally, if the patient still has good hearing at diagnosis and only a small tumor, experienced surgeons in large treatment centers have about a 50% chance of preserving hearing.

Anyone wishing more information can write to the national Acoustic Neuroma Association at PO Box 12402, Atlanta, GA 30355.

Dr. Rebekah Wang-Cheng is a former Professor of Medicine at the Medical College of Wisconsin. Her medical advice column, which answers health-related questions from readers, also appeared in the Milwaukee Journal-Sentinel.