Introduction
NF2-related schwannomatosis (NF2-SWN) is an autosomal dominant disorder leading to the development of schwannomas, meningiomas and spinal cord ependymomas. Younger age is a negative prognostic factor. Treatment includes observation, surgery, radiotherapy and medical therapy with bevacizumab (VEGF monoclonal antibody). Bevacizumab, while not without side effects, demonstrated good results with size regression in around 40% of patients and no change in around 50%. Almost 90% of patients on bevacizumab experienced either an improvement (20%) or no change in their hearing.
Methods
The authors conducted a retrospective study of NF2 patients under 25 years old (adolescents and young adults, AYA) treated with bevacizumab over a 10-year period. Tumour growth was monitored every three months, and assessments included audiograms, word recognition scores (WRS) and routine blood tests. Outcomes in the AYA group were compared with those in adult patients.
Results
Fifteen AYA patients and 22 adults were included in the study. At baseline, 10 of 15 AYA patients and 12 of 22 adults had previously undergone surgery, while 2 of 15 AYA patients and 3 of 22 adults had received radiotherapy. Of the AYA patients, 9 of 15 experienced tumour progression after starting bevacizumab, compared with 5 of 27 adults; this difference was statistically significant. Hearing outcomes did not differ significantly between the two groups. Authors also reported that only 2 of 16 of adults and 1 of 6 AYA patients demonstrated regrowth after stopping bevacizumab. The AYA group also demonstrated a higher average annual tumour growth rate of approximately 3 mm per year compared with 0 mm per year in adults.
The authors acknowledged the limitations of this study including its retrospective nature, incompleteness of data, small sample size and inclusion of patients who already had some sort of treatment. However, the study sheds some light on the effects of bevacizumab on NF2 patients and helps in counselling patients and in the decision making when planning treatment.
