Chemotherapy for Vestibular Schwannoma
Chemotherapy for vestibular schwannoma is currently not standard practice. Chemotherapy is the medical treatment of disease by means of chemicals (medication).
It is most commonly used in the context of cancer treatment. It is sometimes prescribed for benign (non-cancerous) tumours. In vestibular schwannoma it is still mostly experimental and not yet a recognized option for the treatment of single, solitary vestibular schwannoma(VS).
Neurofibromatosis type 2 (NF2) is a genetic condition where patients suffer from more than one benign growth, including vestibular schwannoma. Surgical removal or radiation to control VS are often associated with a lot of side effects and increased morbidity especially hearing loss. As it is now recognized that different types of tumours in NF2 occur at numerous sites, are more aggressive and tend to recur after treatment, medical treatment instead of surgery and radiation may not be such a bad idea.
Lots of research are currently conducted on chemotherapy for VS in NF2 which may later become applicable for the non NF2 sporadic solitary VS we most often encounter.
The current unanswered questions regarding chemotherapy for VS are what the end points of treatment should be. Will the chemotherapy stop the tumour growing or will it cause the tumours to disappear? Will it preserve hearing and vestibular function and if so for how long should patients be treated for? Since NF2 is often seen in younger patients, long-term side effects of chemotherapy should be taken into account. Unfortunately, enough data is not currently available. One would not like the chemotherapy to induce more long term problems and chronic side effects with daily use as the VS itself.
Two drugs currently used and under investigation are:
1. Bevacizumab. This is a suppressant of blood vessel formation and reduces the blood supply to tumours (reduce vascularization).
2. Erlotnib. This is a suppressant of Schwann cell growth and causes the tumour to stop growing.
Research ongoing in Massachusetts, USA and other units will hopefully result in a cure for VS without surgery or radiation.