Sunday May 25, 2008

Treating cancer at subzero temperatures

By LIM WEY WEN

The Star

For cancers that could not be cut out, doctors have another option: freezing cancer cells to death.

WITH flawless skin and jet-black hair, Lina Leonard is the last person you would suspect to have cancer.

Diagnosed with osteosarcoma (bone cancer) two years ago, she was paralysed for about a year due to the disease.

To freeze tumour tissues, a cryoprobe is inserted into the tumour through the skin with the guidance of imaging techniques such as the ultrasound. The tip of the probe delivers gas used for cooling and slowly freezes the cells around it.

“After going through chemotherapy and a bone marrow transplant, I could walk again, but the therapies did little for my lung tumour,” said the 22-year-old Dane in an interview with Malaysian journalists in Guangzhou, China.

After about six months, Lina’s cancer spread again. A CT scan detected a tumour the size of a mothball in her pleura – the thin lining covering her lungs.

Shortly after, Lina was hospitalised for hydrothorax. Water filled one of her lungs, and the tumour had grown into the size of an orange and was pushing on her heart.

“This time, with the cancer in my pleura, my only choice was to go for chemotherapy, but I didn’t want to go through it again,” said Lina who was then told by her doctors to just enjoy the time she still had.

But her mother did not give up. Ewa Leonard, who was formerly a medical doctor, stumbled upon a hospital’s website with extensive information about cryoablation and cryosurgery.

“My mother was convinced and we decided to write to Prof Xu (Kecheng), who is the director of the hospital,” Lina said.

It took Lina and Ewa only three days to hop on a plane to China when cancer specialist Prof Xu agreed to treat Lina’s cancer.

Professor Xu Kecheng ... When most cancer patients find out about their cancer, it is often non-resectable (cannot be cut out) and at times, radiotherapy and chemotherapy is not efficient anymore.

“After we reached the hospital, the doctors immediately went on with cryosurgery, and later chemotherapy. They treated the cancer aggressively,” Lina recalled.

“Only after one month, we saw about a 30% to 40% total necrosis (cell death) of the tumour,” said Ewa.

Now, after four cryosurgeries and chemotherapy, Lina has two very small tumours left. “The doctors have removed eight of them,” she said.

“Normally, when treating cancer tumours, traditional therapies are surgery, chemotherapy and radiotherapy. But these therapies can only treat about 20% of cancer patients,” said Prof Xu.

“For 80% of them, when they find out about their cancer, it is often non-resectable (cannot be cut out) and at times, radiotherapy and chemotherapy is not efficient anymore,” he said, adding that often patients are too weak to receive radiotherapy or chemotherapy.

So, we offer other options, such as photodynamic therapy, cryosurgery and iodine-125 seed implantation for these patients when traditional therapies don’t work, Prof Xu explained.

Cryosurgery - destroying cells by freezing

Dr Niu Lizhi ... Cryosurgery can be done on any part of the body.

“Cryosurgery has a long history and has been used to treat diseases such as warts,” said Dr Niu Lizhi who has vast experience in cryosurgery.

Cryosurgery, otherwise called cryoablation or cryotherapy, is the destruction of tissues – generally, tumour tissues – using very low temperatures (-1960C to -1870C) produced by liquid nitrogen or argon gas respectively.

“This destruction is in situ. That means you don’t remove the tissue that you freeze, and the tissues will be reabsorbed by the body when destruction happens,” said Dr Franco Lugnani, president of the International Society of Cryosurgery (ISC).

In 1974, the International Society of Cryosurgery was founded as many doctors (in urology, dermatology, hepatology and gynaecology) used liquid nitrogen to destroy tissues, he added.

“Of course, in those days, you could apply liquid nitrogen somewhere but it was very difficult to control how the liquid nitrogen, at freezing temperatures, is delivered. And we do not have imaging modalities – we just have our eyes and our fingers,” Dr Lugnani said. Approaching the 90s, the advent of new imaging modalities like the ultrasound and CT scan had revived interest in cryosurgery.

“Eventually, we are able to control what we were delivering inside the body,” Dr Lugnani explained.

Cryosurgery can be used in two different aspects, he said. It can be used when conventional treatment modalities – surgery, chemotherapy and radiotherapy – has failed, especially in cancers of the lung, pancreas, uterus and breast.

Dr Franco Lugnani ... Treatments like surgery, chemotherapy, radiotherapy and cryosurgery that can be used at the same time to kill or control lung cancer.

There are also situations where cryosurgery can be used as first line treatment, for instance in kidney, prostate, some liver and some lung cancers, Dr Lugnani said.

Complementary rather than alternative

“Cryosurgery can be done for any part of the body, from head to toe,” Dr Niu said.

Performed mostly under local anaesthesia, cryosurgery can be used to treat tumours that could not be removed for early or end stage cancer.

“For those that are beyond surgery or other treatments, cryosurgery aims to extend survival,” he continued.

End stage cancer patients can still benefit because destroying the primary tumour seems to have a good effect on distant metastasis, Dr Lugnani said.

“In the past, cryosurgery was done with open surgery, but we do it percutaneously (needle puncture of the skin) under ultrasound or CT scan because cryoablation is less likely to completely remove the tumour (as compared to surgery),” said Dr Niu.

According to a study by Prof Xu and a group of doctors – published in the World Journal of Gastroenterology in March this year – 326 patients with non-resectable liver tumours who underwent percutaneous cryosurgery showed an overall survival rate of 78% over a year and 23% over five years.

Although the study concluded that percutaneous cryosurgery was a safe treatment for liver tumours, doctors in the study chose to view the procedure as an additional means or complement rather than an alternative to hepatectomy (surgical removal of part of the liver).

With the advent of imaging techniques such as the ultrasound,cryosurgery can now be done percutaneously (needle puncture of the skin). In this picture, doctors performing cryosurgery are looking at an ultrasound image to locate the tumour before proceeding to insert a cryoprobe.

Even so, recurrence is a big problem with cryosurgery, Dr Niu added. That is why patients with recurrence may need to have more cryosurgeries done, Dr Niu said.

Otherwise, side effects of cryosurgery are similar to a conventional surgery. In simple words, you can cut something you shouldn’t, freeze the wrong place, or cause complications because you destroyed certain tissues, Dr Lugnani said.

However, for some cancers where operation is not possible because it may cause bleeding, cryosurgery can be applied. “Tumour cells are frozen to halt blood supply, making resection (cutting) possible,” Dr Niu said.

In Malaysia, although cryosurgery has been available for certain disease indications in dermatology, it is not widely used to treat cancer, said Malaysian Oncological Society acting President Datuk Dr Mohd Ibrahim A. Wahid.

Combining therapies

Although cryosurgery has its pros and cons, studies done by doctors found treatment modalities to be more efficient when two or more are used together.

One of the examples is an observation of 50 patients with non-small cell lung cancer who received the combined treatment of cryosurgery and brachytherapy (radioactive iodine-125 seed implantation). In that study, published in Prof Xu and Dr Niu’s book Cryosurgery for Cancer, 32 patients who had been followed-up had 68% survival rates over one year.

This coincides with findings by scientists in the US, who showed in their study – on mice with lymphoma (a form of blood cancer) – that a combination of two chemotherapy drugs is more efficient than either of them used alone.

“In the same way, modalities like surgery, chemotherapy, radiotherapy and cryosurgery can be used at the same time to kill or control lung cancer,” Dr Lugnani said.

“If we can have more than one treatment modality that can attack cancer from different aspects, then we can get better results,” he added.

While most research on cryosurgery is still ongoing, doctors hope that it will become another useful tool in their effort to treat cancer.

“Now, at least in some countries like the US, cryosurgery is the most commonly used treatment modality for small kidney cancers,” Dr Lugnani said.

“But cryosurgery is the new frontier? In a number of years, this may become a treatment of choice.”

You can visit www.orienttumor.com for more information on cryosurgery and other minimally invasive treatments for cancer.