Probe into Error in Khoo Teck Puat Hospital’s Laboratory Test for Cancer Patients

Hazel Asks the Health Minister

Ms Hazel Poa asked the Minister for Health what are the reasons for the wrong test results for cancer patients at Khoo Teck Puat Hospital and what measures will be put in place to ensure that such errors do not occur again.

Dr Koh Poh Koon: Sir, on 19 November 2020, Khoo Teck Puat Hospital (KTPH) was informed by its laboratory that its immunohistochemistry (IHC) tests for Human Epidermal Growth Factor Receptor 2 (HER2) were producing higher-than-expected rates of positive results for breast cancer patients. Preliminary investigations by the laboratory suggested that some of the HER2 results may be inaccurate.

 Following the incident, MOH has been working closely with KTPH to ensure that affected patients are provided with adequate support. KTPH has sent the samples of all patients, who have been tested HER2 positive since 2012, when HER2 testing first started in KTPH, to external laboratories for re-testing to determine how many have received inaccurate results. Preliminary investigations by the KTPH laboratory suggest that the inaccurate results could be due to a suboptimal staining process. The KTPH laboratory has since stopped in-house testing of HER2. MOH has also issued an alert to our other public healthcare institutions to conduct a quick review of their laboratory-developed IHC tests to ensure that positivity rates are within the acceptable range. Thus far, we have not received any reports of similar risks from other healthcare institutions.

 KTPH’s Department of Laboratory Medicine is subject to regular inspection by MOH as part of regulatory processes under the Private Hospitals and Medical Clinics (PHMC) Act to ensure that its laboratory facilities, systems and processes are in place to meet patient and personnel safety standards. In addition, the laboratory is accredited by the College of American Pathologists (CAP), where the last biennial inspections by peers were conducted in 2019.

 As at 23 December 2020, 200 patients have been reclassified from HER2 positive to HER2 negative. Of these, eight patients were treated at private hospitals and 192 patients at Government hospitals. Eight patients are still pending retests. Joint care teams have been formed, comprising KTPH surgeons, histopathologists and the treating oncologists, to review the individual care plans for these affected patients, based on the change in their HER2 status.

 KTPH and the treating oncologists are in the process of actively reaching out to these patients to conduct open disclosure and assess these patients for any potential side effects due to unnecessary treatment. The more common side effects include diarrhoea, chills and fatigue – these are usually short-lasting. About 3% to 4% of those who underwent HER2-directed treatment, for example, using Herceptin, may also experience heart problems. KTPH is also reviewing the bills of these affected patients. The portion of the bills which arose from the unnecessary treatment will be fully refunded. KTPH is also ready to provide any clinical and financial support to the affected patients including on-going or follow-on treatments, if any, which may be needed as a result of this over-treatment.

 The National Healthcare Group has convened an independent review committee, comprising external experts from multiple relevant disciplines in the healthcare industry. The objective is to conduct a thorough evaluation of the incident, to understand better the lapses that have occurred and recommend appropriate measures to improve the process. This ensures that any system gaps are identified and addressed swiftly to prevent recurrence of similar incidents.

 The committee’s investigations are on-going right now and more time would be required to ensure a thorough review. NHG will provide an update when more information is available and these findings will be shared with the other healthcare institutions for improvement. 

Ms Hazel Poa: I thank the Senior Minister of State for his reply. I have a few supplementary questions.

Firstly, while these errors were actually discovered in a review process, since the error actually started in 2012, why did it take so long to discover the errors? Is it a standard timeframe for enough statistics to flag up a possible error? Secondly, would the Ministry consider a second independent test for serious illnesses? The last supplementary question is about compensation to the victims. What sort of compensation is being considered and is a lifetime of free healthcare on the cards?

Dr Koh Poh Koon: Sir, let me clarify the Member’s misconception. When I said in my reply that KTPH is reviewing all the results from 2012, 2012 was taken at a point in which the test first started in KTPH. It does not mean that all the results going back to 2012 are erroneous. So, in that sense, KTPH is being prudent and careful, super kiasu, going back all the way to when the test first started. It may well be that the errors could have occurred in the last three months or six months.

I think the key point usually is when the reagent has been changed. A different brand of reagent or a different provider of the reagent could usually be the starting point of why the protocol or the test conditions were no longer as optimal as they should be.

But going back to 2012 when the test first started was really trying to be comprehensive and to be careful, to make sure that we do not miss anybody in the process. It does not mean that the test was erroneous from 2012. The results of the review are still on-going, so I do not want to prejudge the review process from the experts. Let us wait for the experts to look at all the results going back to 2012 and then decide at which point, what step of the process that could have been where the error occurred.

When it comes to the question of whether you are going to get compensation, as I said earlier, any treatment cost due to the treatment arising from a positive HER2 results, in other words, usually treatment with Herceptin as the drug, the cost of the drug likely would be refunded. Any investigation or tests or treatment of any related complications as a result of, say, Herceptin, would also be refunded as well. But to then say that this translates to a lifetime of compensation, I think that would be a little bit too far a thing to stretch because most of the complications, if any, or most of the side effects relating to the treatment, are transient – diarrhoea, a bit of fever, a bit of chills. They do not have long-term consequences, they are not long-lasting and we have to take that in the correct context of medical treatment.

I hope that answers the Member’s questions.

Ms Hazel Poa: I also had a question about a second independent test for serious illnesses.

Dr Koh Poh Koon: I take that as a general question which in any form of medical diagnostics, if the clinician is unsure that a particular test alone cannot give you a high degree of probability of predicting a positive diagnosis or presence of an illness, then it behoves clinical judgement to call for a second test. But immunohistochemistry is a specific unique test. It does not necessarily mean that an alternative is available. Although in the literature, there are other alternative tests that could be done but we have to consider that against the time needed to do it because that could delay treatment, and also whether that brings on unnecessary costs.

That, I think, we should leave it to the experts to come up with the process guidelines on what is a testing algorithm to decide for Herceptin-related treatment.

Source : Oral Answers to Questions