Hong Kong Sanatorium & Hospital (HKSH) has brought in a new cancer treatment option for its patients with the installation of CyberKnife M6—the latest model in Asia, which shortens treatment time, targets the affected area with a high degree of precision and minimises radiation dosage to normal organs.

“The incidence of cancer has been rising over the past 10 years, reaching to a record high in 2014 with almost 30,000 new cases a year. To take on the challenge, healthcare professionals around the world are looking for treatment options that can achieve high clinical efficiency with fewer side effects. The introduction of CyberKnife M6 at the hospital provides an additional option to Hong Kong patients,” explained Dr Raymond Hin-suen Liang, Assistant Medical Superintendent and Director of Comprehensive Oncology Centre of the Hospital.

Shorter treatment time and fewer side effects than conventional radiotherapy options

For some conventional radiotherapy options, the total dose of radiation needed to kill a tumour cannot be given all at once; especially for patients with tumours of large sizes. Otherwise, this may cause more damages to nearby normal tissues—and potentially, result in more side effects, as compared to dividing the same dose into fractions. Under such circumstances, some patients may need to find alternative treatments because of the long treatment time.

The new model CyberKnife M6 features the unique Multileaf Collimator (MLC) technology, which directs radiation angle and delivers dosage with high precision while avoiding the surrounding healthy tissues. Photo credit: HKSH
The new model CyberKnife M6 features the unique Multileaf Collimator (MLC) technology, which directs radiation angle and delivers dosage with high precision while avoiding the surrounding healthy tissues. Photo credit: HKSH

With the new CyberKnife M6, treatment time can be reduced by half. For instance, a patient with a 5cm lung tumour will have its treatment time cut down by half – to 35 minutes – using CyberKnife M6.

Unlike some conventional options in radiation therapy – whereby patients have to hold their breath during treatment to ensure accuracy and reduce the incidental radiation dose the heart receives – patients can now undergo treatment at ease using CyberKnife M6. Thanks to its indication-specific tumour tracking system, which enables automatic correction during treatment – patients can breathe normally during the treatment. This feature is especially beneficial for elderly patients.

Apart from its ability to shorten treatment time and ensure patients undergo treatment at ease, CyberKnife M6 also comes with enhanced precision.

“The new CyberKnife M6 model  features the unique Multileaf Collimator (MLC) technology, which directs radiation angle and delivers dosage with high precision while avoiding the surrounding healthy tissues, achieving better patient outcomes and fewer side effects,” elaborated Dr Stephen Chun-key Law, specialist in Clinical Oncology of HKSH.

In addition, as compared to conventional options, the CyberKnife M6 model moves with more flexible robotic installation. This, together with MLC which makes use of the tungsten leaves movement to regulate radiation, allows 3D radiation dosage to be delivered accurately. The new model also offers a dynamic tracking of a moving tumour, as its upgraded software is able to generate shaping with continual image guidance, thus allowing radiation dosage to be distinctly calculated and delivered in sub-millimeter accuracy—in spite of moving targets. As a result, treatment can be more targeted and healthy side tissues can be spared.

CyberKnife M6 is applicable to a broad range of tumours

Since the introduction of the CyberKnife M6 service in May this year, more than 40 patients with lung cancer and tumours in spine and brain, have been treated. According to HKSH, some prostate cancer and liver cancer patients have also been treated with satisfactory results.

Dr Wing-hong Kwan shares his experiences in using CyberKnife. Photo credit: HKSH
Dr Wing-hong Kwan shares his experiences in using CyberKnife. Photo credit: HKSH

One of the patients who have opted for the new option at the Hospital is an elderly woman with lung cancer. Her attending doctor, Dr Wing-hong Kwan, who is the Director of Department of Radiotherapy and Associate Director of Comprehensive Oncology Centre of the Hospital, said the size of the tumour is about 5 cm in diameter. “This patient – almost 90 years old – is not a surgical candidate. Result of tradition radiotherapy to treat such a large lung tumour is usually palliative. With its unique tumour tracking capability and sharp radiation dose fall off, ablative radiotherapy can be pursued with a curative treatment.”

The non-invasive, non-surgical radiation treatment option is applicable to a broad range of tumours in the body, including lung, liver, brain, spine, prostate, pancreas and kidney.

Nevertheless, CyberKnife M6 also comes with certain limitations, one of which is it cannot be applied effectively to cancer which has already spread. CyberKnife is not suitable for treating large volumes as its principle of delivery is ‘dose painting’ from one edge of the tumour to the other.

Kwan also pointed out the new CyberKnife M6 service is approximately 10% more expensive than the conventional radiotherapy options. MIMS

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