Combined therapy cures the incurable
A range of new treatments make cancer 'more like a chronic disease', writes Tsang Shuk-wa
NEW CANCER treatments discovered in recent years have boosted the doctor's armamentarium so much that the once incurable disease can now be brought under control.
'In the old days there was no cure for stage-four cancer, but now targeted therapy can be used to suppress it,' said Kevin Loh, an oncologist at the AmMed Cancer Center . 'With cancer under suppression, the patient can live a normal life.'
Oncology specialists are increasingly using surgery and radiation to shrink a tumour, then prescribing chemotherapy and targeted therapy drugs for suppression, Dr Loh said.
Oncologist Diana Siu said a variety of new drugs made treating cancer 'more like treating a chronic disease'.
William Foo, the director of the Radiotherapy and Oncology Centre at the Hong Kong Baptist Hospital, said doctors normally used multi-modality treatments, even in the early stages of cancer.
Between 50 per cent and 60 per cent of stage-one breast cancer cases are now treated with a combination of surgery, chemotherapy and hormonal therapy. This method reduces the risk of a relapse by 25 per cent to 40 per cent in the long term.
'That means the cure rate is higher and the death rate is lower,' Dr Foo said.
'More than 20 years ago, when I was still a student, surgery or radiation alone was considered enough for early-stage cancer. Now, multi-modality treatment is the norm. No matter how early or advanced the cancer, we use a combination of surgery, radiation, chemotherapy and hormonal therapy. Only in very few cases do doctors use surgery, radiation or chemo alone. For advanced-stage cancer, multi-modality is used by default because of the high risk of relapse.'
The effectiveness of the combined treatment is evident in cases of cervical cancer, where the survival rate has improved up to
15 per cent when chemo and radiotherapy are used together.
'Previously, 60 out of 100 patients survived. Since 2000, with the combined treatment, 70 out of 100 survive,' Dr Foo said.
He said that since 2000, chemo plus radiotherapy had become the standard treatment for cervical cancer.
The use of chemo and radiotherapy together has also extended the life span of stage- three lung cancer patients by three to five years. 'Stage-three lung cancer treated by radiation alone achieved nothing. The survival rate was almost zero,' he said.
In cases of colon cancer, the relapse rate has been lowered from 30 per cent to 20 per cent with surgery and chemo drugs prescribed together. The number of colon cancer survivors has increased from 70 per cent to
80 per cent. Breast cancer mortality rates had also improved significantly, despite an increase in the number of breast cancer cases, thanks to multi-modality treatment combining surgery, radiotherapy, chemotherapy and hormone therapy.
The cure rate for breast cancer was now 60 per cent to 70 per cent, Dr Foo said.
The latest equipment for radiotherapy and new drugs for targeted therapy also cause less 'collateral damage' during treatment.
'Patients can now receive a higher dose of radiation targeting the diseased organ more precisely, thereby sparing the normal organs,' he said.
'Targeted therapy based on molecular biology works on molecular pathways and endocrine pathways and uses anti-bodies to target the cancer cells. It attacks only specific targets, unlike in chemo, which may damage the bone marrow, so the collateral damage is low.'
In certain cases, however, multi-modality treatment can result in 'overkill'. These cases include early-stage cancer with a low predicted relapse rate, or aged advanced cancer patients with other medical conditions such as heart disease and diabetes, Dr Foo said.
Dr Loh said technological advancements in cancer treatment meant that more patients could keep their organs.
'In the past, a bladder cancer patient would have their bladder removed and carry a urine bag outside their body.
'Now we can use chemo and radiotherapy instead of surgery, and the bladder can be preserved,' Dr Loh said.
'Throat cancer patients used to have their voice boxes removed as a matter of routine. Now 60 per cent to 70 per cent of them can keep their voice boxes.'
In cases of breast cancer, the radical removal of the breast, including chest muscle, was routine 15 to 20 years ago. Now overseas statistics show that up to 60 per cent of breast cancer cases do not require breast removal. In Hong Kong, 30 per cent to 40 per cent of breast cancer patients keep their breasts.
The lower average compared to the US is mainly the result of a lower detection rate, Dr Loh said.
Advances in radiotherapy equipment allow the delivery of high dosages with a precision comparable to surgery.
'Stereotatic radiation surgery can even target a small lump in the head and not damage the brain. The Gamma Knife can deliver a high dose to destroy the tumour, but it is limited to treating brain lesions.
'Now there is Cyber Knife, which can be applied to other parts of the body. It can deliver a high dosage in one go to destroy a targeted area while not affecting other organs.'
But the machine is expensive and is not yet available in Hong Kong.
The most effective applications for Cyber Knife are in cases of brain, lung, liver, prostate and pancreas cancer.
Despite advances in treatment and reduced side effects, radiation cannot replace surgery, he said.
For localised disease in the brain, Victor Hsue, a specialist in clinical oncology, prefers using the X Knife in radiotherapy.
'Gamma Knife is effective for treatment of spherical tumours because of its predetermined spherical coned design. The cost of the machine is relatively expensive with limited application. X Knife is preferred as it is very versatile and is an add-on equipment to regular radiotherapy machine. The dose calculation is more precise,' he said.
Improvements in diagnostic technology have also enabled doctors to more precisely determine the size and position of a tumour.
One disadvantage in using different forms of treatment is that patients must endure the side-effects of each treatment type.
However, chemo drugs are now less toxic, giving patients more benefit and less suffering.
Anti-emetics for controlling vomiting, for example, had advanced after two generations of improvements, Dr Foo said.