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- Oncologist Joanna Lin
Elaine Young explains why cancer sufferers must eat well if they are to fight the disease.
The weight of cancer patients has a huge impact on their survival rate. And unlike illnesses such as diabetes, heart disease and hypertension, it is not the excess kilos that cause problems, but a lack of them. Cancer-induced weight loss can occur at any stage in patients and experts say that as little as a 5 per cent loss can hinder one's response to cancer therapy and, therefore, survival. Twenty per cent of all cancer deaths globally are associated with malnutrition and weight loss.
This statistic was provided by Dr Joseph Espat, associate professor of general surgery at the University of Illinois in Chicago and a specialist in cancer-induced weight loss. He was in Singapore recently touring hospitals and meeting fellow cancer surgeons.
The reason weight loss occurs at all is because of inflammation, said Dr Espat. Inflammation is the first response of the immune system to infection or irritation. He explained it simply: If one is run over by a bus, contracts pneumonia or develops a tumour, the body cannot tell the difference and its immune system merely reacts to fight off an intruder. This can cure the pneumonia or heal the accident trauma but not the tumour: It keeps on growing. The reason that this internal attacker acts differently to an external attack is because the tumour is created from mutated cells and fights back.
Fighting inflammation and the healing process require tremendous amounts of energy and that can lead to weight loss, said Dr Espat. "If you break a bone, the healing of that bone requires 700 calories a day, so you would lose weight. If you get an infection, then it could cost about 800 calories a day. That's why, when you are sick, you lose weight."
The same applies to cancer but more so. He continued: "If you have a tumour, your liver switches from an organ that makes normal proteins to making proteins that fight a tumour. There are receptors in your brain that shut off your appetite and the most important thing is that your lean muscle mass contains very specific proteins that the body can't get any other way than from the liver."
These complex changes cause the body to burn more calories than usual, curb the appetite, reduce muscle mass and eventually lead to weight loss. Weight loss affects people in the early stages of colon, lung, kidney, stomach, rectum, pancreas and head and neck cancer, said the doctor. Cancers like leukaemia, ovarian, breast and prostate cancer cause weight loss in the advanced stages.
Cancer patients do not lose weight rapidly, he said, and that is why people do not notice the problem. And family members who try to induce cancer patients to eat have a battle because the patients' perception is that they are eating. They stop eating when they are full. However, for those with no appetite that full threshold is reached quicker.
Dr Joanna Lin, an oncologist in private practice in Mount Elizabeth Medical Centre, gave the Singapore perspective: "Cancer-induced weight loss is universal. It doesn't have any racial or cultural boundaries. Weight loss can be the first presenting complaint of cancer." She said people are becoming more aware that cancer-induced weight loss is actually a bad sign, an indication that the ultimate survival of the patient may be impeded.
"If a well patient, at diagnosis, can remain reasonably well and maintain their weight, then they will do a lot better than one who is losing weight."
Dr Lin explained that significant weight loss occurs when one sheds anything more than 10 per cent of one's body weight. She said patients often come in with self-induced weight loss because of the perception that things like chicken and sugar are harmful for them.
"Asians don't generally eat a lot of protein in their diet so they tend to cut it out even more when they get sick. That's probably the worst thing they can do as it just accelerates their deterioration," she said. Protein does not come just from red meat. It is found in eggs, nuts, beans and soya products. To guard against cancer, the American Cancer Society recommends taking antioxidants to boost the immune system, and especially the trace mineral selenium.
It also suggests only one or two red meat servings per month, lots of green leafy vegetables and as many helpings of fresh fish that one can consume. This is also the diet that Dr Espat and his colleagues suggest for their cancer patients. But for those already on a spiral of weight and appetite loss, something else has to be added.
"You need protein, essential fats and calories, so you are not going to get that unless you buy a supplement," said Dr Espat.
"You can buy low-carbohydrate bars but they are designed for weight loss, not gain. The solution, then, is a nutritional therapy like ProSure® that contains omega-3 fatty acid EPA (eicosapentaenoic acid), fibre, vitamins and minerals."
Omega-3 is the fatty acid found in the fish that the Cancer Society includes in its cancer-prevention diet. And Dr Espat notes that an omega-3 supplemented diet is good for reducing inflammation in cancer-induced weight loss.
But some patients dislike nutritional drinks that look and taste like milkshakes, which many do. Said Dr Lin, "The older generation are not used to taking dairy or what is perceived to be a dairy product. A lot of the nutritional drinks that are available appear to be lactose-based because they taste milky, even though they are not." Her alternative is to offer nutritional drinks in fruit flavours. Or she will suggest tasteless protein powders to sprinkle on food.
Poor nutritional health has an effect on treatment too. Said Dr Lin: "Most treatments nowadays are not as toxic as they were 10 or 20 years ago, but there is still the risk of loss of appetite with chemotherapy and radiotherapy."
When it comes to radiotherapy, or radiation therapy, said Dr Espat, the patient has to be strong enough to complete the course. "Your cells remember the amount of radiation you get. If you interrupt it, you have damaged cells, not dead cells. So if you are losing so much weight, and you are depressing your immune system on top of the immune suppression you get from chemotherapy, then you may have your treatment reduced or stopped in the future."
But the doctors can only do so much. Dr Lin's advice for the family is to look at the content of a patient's intake and not the volume. She said: "A lot of Chinese families like feeding the cancer patients porridge and soup, which is actually just water. There is no point giving them soup all day where the calorie content is minimal when they can go on to one of the nutritional supplements that contain around 250 calories in a packet."
If all else fails, she said, the patient has to be fed intravenously. This is not ideal, she said, but it will be done if the weight has to be kept stable.
Dr Espat does not mince his words with his patients. "I stop telling people that I'm going to cure them, I tell them that I'm going to take their cancer and make it a chronic disease."
Pancreatic and gastric cancer will likely return after remission, he warned, but he says that patients with these cancers can have a good quality of life, and an extended life at that.
"That's the point of cancer care today,' he said. 'Minimise interventions and give you what you want most. And most people would put eating a meal in a restaurant really high on their list."
E-mail: elainey@sph.com.sg
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