Weighing up the cost of Lynch syndrome screening

Cancer

By Mardi Chapman

19 Apr 2018

Lynch syndrome screening for patients with bowel cancer diagnosed before age 70 is cost effective given the potential for identifying at-risk family members who would benefit from intensive surveillance.

However the additional cases detected compared to only screening younger patients come at a cost.

The Australian study also found that screening with MMR immunohistochemistry then MLH1 methylation was more cost effective than the alternative BRAF V600E testing.

The cost effectiveness study modelled case yield and costs for both screening pathways for different age groups at diagnosis and for universal screening.

Using the MLH1 pathway, it found screening 1,000 bowel cancer cases detected before age 50 would identify about 5.2 cases of Lynch syndrome and cost about $7,041 per case.

Adding in screening of 50-59 year olds would find an extra 1.5 cases and cost $10,999 per case; expanding the program to include 60-69 year olds would identify another 1.6 cases at a cost of $15,685 per case.

Screening every case of bowel case for Lynch syndrome blew out the cost per case to $35,784 but universal screening would not reveal any new cases of Lynch syndrome.

Professor Peter O’Leary, from Curtin University and PathWest Laboratory Medicine, told the limbic universal screening would be a huge impost on the budget.

“Clearly, our data showed that the more you increase the age, to under 70 or universal screening, then you are going to get a lot more people in there who go on to further testing and that is going to be more expensive.”

“And the yield is lower because, as people get older, the risk of CRC increases whereas Lynch syndrome generally occurs in younger people. That’s why most places around the world have selected 60 years as the general cut off for screening for Lynch syndrome.”

He said the decision ultimately became an economic one and that MSAC was currently considering the value of rebating genetic tests for bowel cancer.

“At the moment, certainly in WA, genetic testing for Lynch syndrome is done by PathWest and essentially covered by the state government. There is no Medicare rebate.”

Gastroenterologist and co-author Dr Hooi Ee, from the Sir Charles Gairdner Hospital in WA, said NHMRC-endorsed guidelines suggest all CRCs should be tested for MMR deficiency as a means to subsequently identify Lynch syndrome.

“But that’s not what our data supports due to the high cost for universal testing. If you test everyone, the number of extra cases you pick up are so small, is it worth spending the extra money?”

He said Lynch syndrome was relatively uncommon but should be seriously considered in people diagnosed with bowel cancer before age 60 and those with other characteristic cancers such as endometrial cancers.

“The other important thing about Lynch syndrome is it is hard to know they’ve got it without being genetically tested. If they have FAP, you will find polyps everywhere so it will give you a clue.”

“Lynch syndrome has no other clues but by testing you know who to scope more frequently and who to watch more closely.”

Professor O’Leary said the benefit of identifying a case of Lynch syndrome was the cascade testing through the family.

“The major challenge is to encourage those people to go on and have further diagnostic testing and to involve their families in acknowledging their greater risk of developing CRC and that they should take measures to minimise that risk.”

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