SINGAPORE: About 90 breast cancer patients may have received "unnecessary treatment", after a test that classifies the status of a patient produced inaccurate results, said Khoo Teck Puat Hospital (KTPH) on Friday (Dec 11).
About 180 breast cancer patients are estimated to have been inaccurately classified as HER2 positive and may be reclassified to HER2 negative, said KTPH.
AdvertisementAdvertisementHER2, or Human Epidermal Growth Factor Receptor 2, is a gene that controls how a healthy cell grows, divide and repairs itself.
According to Mayo Clinic, HER2-positive breast cancers tend to be more aggressive than other types of breast cancer.
KTPH first started testing patients for HER2 in 2012. The test is conducted to classify a patient's status and guides treatment options; it does not diagnose whether a person has cancer.
The hospital said that it was informed by its laboratory on Nov 19 that its immunohistochemistry (IHC) HER2 tests were producing higher-than-expected rates of positive results.
AdvertisementAdvertisementIn an IHC HER2 test, the tissue sample from a patient is "stained" with antibodies that have a coloured dye. These antibodies will attach themselves to HER2 proteins and a doctor will read the slide under a microscope to classify the sample.
Preliminary investigations by the laboratory suggested that an "incorrect staining process" for the test had produced inaccurate HER2 results, said KTPH.
The hospital reported the incident to National Healthcare Group (NHG) on Nov 22 and the Ministry of Health on Nov 24.
SAMPLES DATING BACK TO 2012 AFFECTED
AdvertisementKTPH said it has investigated the extent of the issue and identified all the affected patients since it was discovered.
Based on initial estimates, about 180 breast cancer patients may be reclassified from HER2 positive to HER2 negative.
About half of these patients may have received unnecessary treatment for HER2, usually the drug Herceptin.
Common side effects of Herceptin include diarrhoea, chills and fever. About 3 to 4 per cent who undergo Herceptin treatment may also experience heart problems.
"The treatment regime of affected patients will be reviewed by their oncologists," said KTPH.
The patients' samples, dating back to 2012, have been sent to various external laboratories to expedite re-testing for HER2, added KTPH.
"As some of the retest results return, the hospital has begun reaching out personally to patients and their treating oncologists to offer support. This process of contacting patients is still ongoing," it said.
The laboratory has stopped in-house IHC HER2 testing to ensure patient safety, said the hospital.
NHG has also convened an independent review committee, which includes external experts, to do a thorough review of how the incident happened. This is to improve the process and prevent similar incidents from happening again.
"I would like to convey my deepest apologies to all the affected patients, their families and their treating oncologists," said Mrs Chew Kwee Tiang, CEO of KTPH.
"I am very sorry that they have to go through this. We will provide all the necessary support and assistance, and will do our best to take care of them."
She added that KTPH treats this incident "very seriously" and will take all necessary steps to ensure it does not happen again.
Patients who have any related queries may contact KTPH at 6602 3333.
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