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New method of diagnosis

The Straits Times (21 February 2017) - A new method of diagnosing prostate cancer that is better able to detect aggressive tumours is more readily available here.

Since May last year, more than 80 patients at Tan Tock Seng Hospital (TTSH) have undergone an MRI (magnetic resonance imaging) ultrasound fusion-guided biopsy, which managed to detect 92 per cent of the intermediate- to high-grade cancers.

In contrast, only 62 per cent of these aggressive cancers were detected through the traditional ultrasound-guided biopsy, said adjunct assistant professor Tan Yung Khan, a consultant at the hospital’s urology department. The remaining 38 per cent were missed or undiagnosed.

Like the traditional method, the fusion technique at TTSH is done under local anaesthesia. Since October last year, Parkway- Health Radiology has also been offering this fusion prostate biopsy, which is available at Mount Elizabeth Novena Hospital. It has seen about60 cases so far.

Singapore General Hospital and the National University Hospital (NUH)both offer the fusion-targeted biopsy, but they use a different system where the biopsy is usually done under general anaesthesia.

Prostate cancer, which occurs in the small prostate gland which secretes fluids that help in reproduction, is very common in men.

However, Dr Tan said the standard biopsy is done blindly as the prostate tumour cannot be seen with an ultrasound scan. A dozen or more tissue samples are taken randomly from the prostate to test for cancer. This means mistakes can occur – cancers can be missed or an aggressive one can be mistaken for a low-grade one.

Dr Low Kah Boon, a consultant radiologist at ParkwayHealth Radiology, said: “The fusion biopsy incorporates MRI, which acts as a roadmap to let the urologist know where to take the biopsies.”

Assistant Professor Lincoln Tan, a consultant at the NUH urology department, said it was only in recent years that the quality of MRIs had improved, allowing for suspicious cancerous areas within the prostate to be better seen.

However, he added, the detection of prostate cancer through MRI fusion-guided biopsy is dependent on factors such as the imaging quality of the MRI scans and the expertise and experience of the radiologist in identifying suspicious lesions; the accuracy of the fusion software and biopsy platform, and technical skill of the surgeon running the biopsy platform.

TTSH’s Dr Tan set up a workgroup at the hospital about two years ago to look into adopting a fusion method.

“We are getting excellent results while performing the biopsies in the clinic under local anaesthesia, thus keeping costs down,” he said. The new method helps to cut down on the number of biopsies done, as a patient who has undergone a targeted biopsy is unlikely to require further biopsies, he said.

TTSH, which carries out about 700 standard biopsies for prostate cancer a year, now expects to use the fusion-guided method on 200 to300patients a year, said Dr Tan. These are patients who have gone through a standard biopsy but are still suspected of having prostate cancer, he said. If not for the fusion method, they would have to repeat the standard biopsy, which can be “traumatic” for some.

The simpler standard biopsy is still the first type of biopsy offered to men suspected of having the disease.

Dr Low said: “The fusion method is particularly useful in negative biopsy cases, where the suspicion of cancer is still high, or when the cancer is in hard-to-reach areas.”


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Source: The Straits Times © Singapore Press Holdings Limited. Reproduced with permission.