Nuclear Medicine is a medical speciality involving the application of radioactive pharmaceuticals in diagnosing and treating diseases. With advanced imaging technology such as 4D PET-CT and SPECT-CT, Sunway Medical Centre’s comprehensive Nuclear Medicine Centre provides both diagnostic and therapeutic care to patients.
In diagnostic nuclear medicine (also known as molecular imaging), single-photon emission computed tomography-computed tomography (SPECT-CT) or positron emission tomography-computed tomography (PET-CT) are the two most common hybrid imaging modalities. Nuclear medicine imaging differs from radiology as the emphasis is not only on anatomy but also on body functions and tumour characteristics.
Dr Lee Boon Nang, a Nuclear Medicine Physician at Sunway Cancer Centre, briefly explained the differences and uses of these advanced imaging facilities.
“At Sunway Medical Centre, we encourage people to come for a proper assessment. A PET-CT scan generally is a sensitive tool in detecting diseases like cancer. It evaluates the spread of disease (staging) accurately, helps to evaluate early disease recurrence, and guides in radiotherapy treatment planning or biopsy. As a biomarker imaging tool, it also helps oncologists to monitor the treatment response.”
“There are three types of PET-CT scans available at Sunway Cancer Centre – FDG 18 PET-CT scan to diagnose various cancers, Gallium 68 DOTATATE PET-CT scan to diagnose neuroendocrine tumours, and Gallium 68 PSMA PET-CT scan to diagnose prostate cancer,” Dr Lee added.
“Sunway Medical Centre is also equipped with SPECT-CT scan. A SPECT-CT scan is another useful diagnostic tool, especially for a bone scan, to evaluate the bone metastases for prostate and breast cancer patients.”
A 2018 study showed that cancer is the second most common cause of death worldwide and in Malaysia—and the number of cancer cases in Malaysia has been increasing year on year (Malaysian National Cancer Registry Report 2012-2016).
Among hundreds of cancers nowadays, this article explores two types of cancer that most people are unaware of: neuroendocrine tumours (NET) and prostate cancer, and how targeted radioligand therapy treats these cancers.
NETs and PRRT
NETs are tumours mainly from the digestive tract—stomach, intestine, pancreas—and lungs, and their incidence has been steadily increasing in the last three decades.
Surgery is the mainstay of treatment for neuroendocrine tumours. When the tumour has spread or is inoperable, other treatment options include targeted therapy, hormonal therapy, chemotherapy, and targeted radioligand therapy called peptide receptor radionuclide therapy (PRRT).
(What is PRRT)
PRRT is one of the latest advanced treatments under nuclear medicine. It significantly targets cancer cells that express specific receptors called somatostatin receptors.
PRRT combines a drug that targets cancer cells with a small amount of a radioactive substance. It allows radiation to be delivered directly to the cancer cells. PRRT radionuclides such as Yttrium 90 (Y-90) and Lutetium 177 (Lu-177) are widely used to treat advanced neuroendocrine tumours.
(What conditions are treated)
PRRT is used to treat NETs arising from the stomach, intestine, pancreas, and lungs, as well as rare tumours pheochromocytoma and paraganglioma.
Dr Tan Teik Hin, a Nuclear Medicine Physician at Sunway Cancer Centre, explained, “PRRT is an effective treatment for patients who have advanced (metastatic) and/or progressive neuroendocrine tumours. PRRT should be considered for those who are not candidates for surgery and whose symptoms do not respond to other medical therapies.”
“Although the main goals of PRRT are to stop or slow down tumour progression, provide symptom relief, and improve quality of life and overall survival, tumour shrinkage is usually observed. Moreover, we do see patients who completely responded to this therapy,” Dr Tan added.
“As a targeted agent, the side effects are generally well-tolerated. Most patients are usually discharged after a day of observation in the ward.”
Prostate cancer and PSMA therapy
Prostate cancer is one of the most common cancers in men. The new prostate-specific membrane antigen (PSMA) PET imaging significantly improves how prostate cancer is detected and treated.
This latest ground-breaking treatment called Lutetium 177-PSMA therapy is for those;
- whose prostate cancer has spread and becomes resistant to hormonal therapies
- who are unsuitable for or have failed chemotherapy
- who have uncontrolled bone pain
PSMA (Lu177-PSMA therapy) is a type of molecular therapy used to treat metastatic prostate cancer. Lutetium-177 is a radionuclide substance that emits damaging radiation, which will destroy cancer cells. It is combined with PSMA protein that seeks out PSMA receptors found on most prostate cancer cell surfaces. Once Lutetium-177 PSMA is infused into a patient’s bloodstream, it will target and bind to PSMA receptors on prostate cancer cells. Damaging radiation from the Lutetium-177 will, over time, result in the death of prostate cancer cells.
Treatment can be done in a daycare setting. The Lu177-PSMA drug will be given by slow intravenous injection. The drug administration process will only take around an hour to complete.
PSMA therapy is highly targeted and minimally invasive, as it does not involve surgery or chemotherapy. As compared to other treatment options, PSMA therapy has tolerable side effects and significantly improves both quality of life (QOL) and survival.
Nuclear medicine treatment involves a multidisciplinary team that includes consultants, nurses, radiopharmacists, medical physicists, nuclear medicine radiographers, etc.
“The advantage of a large hospital like Sunway Medical Centre is that we can provide not only comprehensive cancer treatment but also other forms of complementary therapies such as diet and physiotherapy,” remarked Dr Ivan Shew Yee Siang, a consultant clinical oncologist at Sunway Cancer Centre.
“We are a one-stop centre for cancer treatment where we provide everything from screening, diagnosis, and treatment to palliative care and survivorship care.”
With the advanced technologies and comprehensive care, patient outcomes have significantly improved in recent years. The following testimonial is recorded by one of the many cancer survivors discharged from Sunway Cancer Centre, highlighting how we have been “transforming the lives we touch.”
“In 2018, I suddenly collapsed at my workplace. When I was brought to the hospital, I was diagnosed with a rare type of neuroendocrine tumour called insulinoma,” said a patient who was recently discharged from Sunway Cancer Centre after completing his last cycle of PRRT.
“When the tumour was discovered, it had already spread to the liver. I was told that surgery was not possible. Then, I was started with diazoxide, steroid, hormonal and targeted therapy to control the disease and its symptoms. However, the tumours did not respond to these medications. My symptoms did not go away. I still had hypoglycaemic attacks on and off. Every day, I would keep some sweets in my pocket, just in case I develop low sugar reactions. Sometimes, I would have loose stool.”
“After a year or so, I was referred to Sunway Medical Centre for PRRT. After consulting with Dr Tan, I began my first cycle of PRRT treatment in 2019. My sugar level normalised, and some medications were taken away after two cycles of treatment. My diarrhoea had also improved.’’
“It was a straightforward procedure. Some pre-medications were given in advance to protect my kidney. Then a special infusion of the radioisotope was given, which only took about 20 to 30 minutes. The next day, I was put on a scanner called SPECT-CT. This scan would tell me where the radioisotope had travelled and how it attached to the tumours. I was allowed to go home after the SPECT-CT scan. There were no obvious side effects except some nausea and malaise, which were controlled by medication. I was back to normal within one to two weeks after treatment.”
In Feb 2020, when he completed his 4th PRRT, he was told that all the tumours have regressed on the SPECT-CT scan, and he was in remission. “After battling this disease for over three years, the news could not have been better.”
Sunway Medical Centre
5, Jalan Lagoon Selatan,
47500 Selangor Darul Ehsan
Fax: +603 8601 1069
Tel: +603 8601 1074