Poster Presentation COSA 2015 ASM

A survey of the current provision of screening tumours for mismatch repair deficiency in Australia: An Inherited Cancer Connect Partnership (ICCon) initiative (#377)

Lyon Mascarenhas 1 , Alex Boussioutas 1 2 3 , Sue Shanley 1 , Robyn Ward 4 , Nicholas Pachter 5 6 , Finlay Macrae 2 3 , Stephen Fox 1 , Gillian Mitchell 1 7 , Elaine Duxbury 8 , Daniel Buchanan 3 , Amanda Spurdle 9
  1. Peter MacCallum Cancer Institute, East Melbourne, VIC, Australia
  2. Royal Melbourne Hospital, Melbourne
  3. Department of Pathology, University of Melbourne, Melbourne, VIC, Australia
  4. Prince of Wales Hospital, Sydney
  5. University of Western Australia, Perth
  6. King Edward Hospital, Perth
  7. BC Cancer Agency, Vancouver
  8. Cancer Action Victoria, Melbourne
  9. QIMR Berghofer Medical Research Institute, Brisbane

Background:Previous studies have demonstrated that screening for LS in all new cases of colorectal cancer(CRC)&endometrial cancer(EC)is feasible and detects significant number of patients with germline MMR mutations

Aim:To survey current availability of screening for tumour MMR deficiency and the triggers for MMR assessment at point of colorectal/endometrial cancer diagnosis in both public and private laboratories throughout Australia.

Methods:Heads of RCPA accredited laboratories in Australia were invited by email to participate in an online survey. Non-responders were invited to complete the survey by telephone interview. The proportions of laboratories offering testing for mismatch repair immunohistochemistry (MMR IHC), microsatellite instability (MSI), BRAFV600E mutation and MLH1promoter methylation were calculated.

Results:At the time of submission, from 49 laboratories invited to participate, 37 pathologists (76%) have responded to this survey. 78% responders had MMR IHC capability,16% offered MMR IHC+MSI testing,6% did neither. For CRCs, the majority of laboratories 54% are routinely screening all specimens for MMR,6% test on clinician request,23% select cases based on red flag criteria.17% test on red flag cases when not requested by clinician. For EC;26% labs are universally screening all EC,37% upon clinician request,26% test on red flag cases,11% test on red flag cases when not requested by clinician.24% have the resources to offer MLH1 methylation testing but only 11% are actually testing for MLH1 methylation.43% carry out somatic BRAF V600E instead of MLH1 methylation.Data collection is still ongoing

Conclusion:It is promising that large proportion of laboratories have already established universal screening of all new cases of CRC for evidence of MMR deficiency whereas screening in EC is largely triggered by clincian request. Few laboratories are offering MLH1 promoter methylation testing although more laboratories have the capability to do so if required.The strong published evidence for universal testing of new cases of CRC/EC warrants a standardised national policy for screeningMMR mutations.This survey demonstrates a significant variation in laboratory practices and capability and can be used to guide the development of a national policy of MMR screening

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