Lynch testing for all patients with endometrial cancer

Posted 9 years ago by Andreas Obermair

Lynch Syndrome is a familial cancer syndrome responsible for endometrial and bowel cancers. In female carriers of Lynch, endometrial cancer is the most common cancer type. For more information on Lynch Syndrome, please go to obermair.info and type “Lynch” into the right hand bottom search field or click here.

One major problem with Lynch is that it often goes undetected. In other words, if patients don’t know they have Lynch they might …

1. Develop several more avoidable secondary cancers,
2. In addition, family members may also develop preventable cancers

Recognising a patient with Lynch is a true life saver!

How do we identify Lynch carriers?

In this day and age, it would be infeasible to test the entire Australian population for Lynch.

Instead, we recognise sentinel cancers. For example, a patient (male or female) gets diagnosed with bowel cancer, the tumour will be tested and Lynch syndrome may be diagnosed. As a consequence, all first degree relatives will be offered genetic testing and some of them will be found Lynch-positive. Preventative steps will minimise the cancer risk in Lynch carriers. Relatives who don’t have Lynch can be reassured. 

Missing the identification of sentinel cancers will not only cause harm to the patient herself (subsequent cancers), but also to all first degree relatives who could also claim that they could have known.

What needs to be done?

My colleagues and I went through the research evidence and concluded that all patients diagnosed with endometrial cancer should have Lynch tissue testing.

The test is an immunohistochemical test automatically performed in the pathology lab on endometrial cancer tissue that is already available. No additional blood or tissue from the patient will need to be requested and the test will be cost free to most patients.

Interpretation of results

A positive tissue test is suspicious for Lynch but still not definitive proof. Such a patient needs to be referred to formal genetic testing through a blood test, which I am happy to arrange.

Immmunohistochemistry is far from perfect and I accept that sometimes false positive tests may cause anxiety to some patients. However, the risks of missing a patient with Lynch (including the medico-legal risks) would be devastating.

All major Queensland pathology Labs involved

The issue is so important that all QLD gynaecological oncologists and all major histopathology providers are in support. You will find this additional information about the Lynch status on all histopathology reports for endometrial cancer under “Mismatch repair deficiency”. The terms “Preservation of staining” or “No loss of enzyme activity” indicates the absence of Lynch.

Incidental finding of endometrial cancer

Should a general gynaecologist incidentally discover an endometrial cancer during a hysterectomy, this test will also be performed automatically. The gynaecologist is then welcome to be in touch with any gynaecological oncologist or me to discuss whether or not any further diagnosis or treatment needs to be done.

Overall, I am very excited that the new Lynch testing algorithm will identify a lot more patients who have Lynch. It may help those patients to develop avoidable secondary cancers and it may also help some family members to prevent cancer.