P13: Data from 1100 families used to model investigation strategies in familial bowel cancer

Adam C Shaw1, Louise Izatt1, Anjana Kulkarni1, Deborah M Ruddy1, Nayanta Sodha2, Vishakha Tripathi1, Michael Green3, Gail Norbury1.

1 – Genetics Service, Guy’s & St Thomas’ Hospitals, London. 2 – Molecular Genetics, Viapath, London. 3 – Histopathology, Viapath, London.

Aim

We established a monthly hereditary bowel cancer multidisciplinary meeting (MDM) in 2010 with input from Clinical Genetics, Histopathology & Molecular Genetics. All individuals undergoing testing for hereditary bowel cancer are discussed to decide testing strategy, interpret results and provide surveillance recommendations for relatives. Summary reports are issued. The MDM was instituted to improve governance, but has also provided a valuable dataset for audit and service development.

Method

The dataset was used to model the cost of different testing algorithms. The proportion of Amsterdam and Bethesda positive families in which a pathogenic MMR mutation was ultimately identified allowed comparison of strategies, including MMR gene sequencing as an initial test.

Results

Over 1100 families have been assessed.  Of the 208 families meeting Amsterdam criteria, 12% were found to have a MMR gene mutation compared to 4% meeting Bethesda criteria. Modelling shows that for Amsterdam positive families, performing MMR gene analysis before tumour tests would cost around €1080 per family compared with €450 in converse.

Conclusion

For families meeting Amsterdam criteria, the excess cost of performing MMR gene analysis as the initial test may be justified by savings in time and administration. The MDM approach promotes consistent practice and facilitates audit and service development.

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