B126
Paediatric malignant rhabdoid tumours: a study of clinical and pathological features
Daniel Morgenstern1, Sian Gibson2, Tanya Brown1, Neil Sebire2, John Anderson1
1Institute of Child Health, London, UK, 2Great Ormond Street Hospital, London, UK
Background
Malignant rhabdoid tumours (MRT) and their central nervous system counterparts atypical teratoid/rhabdoid tumours (ATRT) are rare, highly aggressive malignant neoplasms of childhood. Although there are isolated reports of long-term survival with intensive, multimodal therapy, outcomes are generally poor.
Method
We conducted a retrospective review of all patients diagnosed with MRT/ATRT at Great Ormond Street Hospital over the 20 year period 1989-2009. All cases were subjected to expert pathological review and only those with typical rhabdoid morphology and confirmed loss of INI-1 immunoreactivity were included in the analysis. Immunohistochemistry (IHC) for c-Erb/HER and c-Met was performed on tissue sections using standard techniques.
Results and Conclusion
In a final cohort of 34 cases, overall survival was 17.4% with median survival of 10.1 months. Outcome in patients aged less than 3 years was significantly worse than for those aged over 3 years (median survival 6.2 months vs 19.2 months, p=0.0034, log-rank test). Surgical resection correlated with improved outcome and there was a statistically significant benefit of radiotherapy (median survival 14.9 months vs 6.6 months for those no receiving radiotherapy, p=0.0068), although this analysis is confounded by the impact of patient age. It was not possible to analyse the effects of individual chemotherapy agents or regimens. There were 4 long-term survivors (>30 months), all of whom received chemotherapy with or without surgical resection or radiotherapy. Interestingly, two of these were patients with metastatic disease, chest wall / mediastinal primaries and an unusual myxoid histology, which might represent a new MRT subtype.
In view of poor outcomes for MRT/ATRT, there is a clear need for new treatment strategies and the identification of novel molecular targets. We therefore examined expression of c-Erb/HER and c-Met by IHC. However, there was no significant staining for either (proto)oncogene suggesting that these are unlikely to represent useful targets for the treatment of MRT/ATRT.
Acknowledgements
We thank Dr Julia Chisholm and Dr Antony Michalski for helpful comments
