Sunday October 14, 2012
By Drs THO LYE MUN & DANIEL WONG WAI YAN
The facts and fiction of chemotherapy.
WITH reference to the article Therapy in Cancer written by Dr Amir Farid Ishak (Fit4Life, Sept 30, 2012), whilst we can agree that further progress is welcome in the field of cancer, we cannot agree with numerous statements that were made, and ultimately, his conclusion that “the concept of fighting cancer the chemotherapy way is wrong”.
For patients faced with the stark reality of a diagnosis of cancer, they have, in our opinion, the right to have at hand, truthful and unbiased medical opinions in order for them to make informed decisions regarding choices of treatment.
Dr Amir seems to draw his conclusions by citing three journal articles, two of which are 20 years old and one of which is eight years old.
We would urge him to review up-to-date literature on the subject. The field of cancer care is progressing at a tremendous rate, and the way we treat this disease has dramatically changed, even compared to 10 years ago.
Today, the role of chemotherapy has been proven conclusively in the treatment of cancer in the curative setting (eradicating cancer completely), adjuvant setting (eradicating cancer cells still remaining in the body after surgery), neo-adjuvant setting (shrinking an incurable tumour to enable curative surgery to proceed), and the metastatic setting (where the aim may not be to cure, but to extend duration and quality of life).
In breast cancer, chemotherapy is not uncommonly delivered after surgery to eradicate potential cancer cells left behind, which cannot be detected by the naked eye or by scanning (eg ultrasound, CT, MRI or PET).
Take, for instance, the case of a 45-year-old woman who has a breast cancer successfully removed by surgery, but the tumour, under further laboratory inspection, demonstrates aggressive features.
The chances of the cancer coming back, and her succumbing to the disease, unfortunately, are as high as 64% [Lancet, 2012 4; 379(9814): 432-44 and Adjuvant! Online version 8]. That means that out of 100 women in a similar situation, only 36 will be alive in 10 years without any further treatment.
However, with modern chemotherapy and hormone therapy, a staggering 73 patients (out of 100) will be expected to be alive in 10 years.
To us, this represents a complete pendulum shift in favour of people fighting this disease. We are talking about women who are in their prime, who have families, who want to see their children grow up, and who have a lot more to give to society.
Dr Amir mentions that in some cases, chemotherapy may only prolong survival by a month in some types of tumours.
Given the multiple advances and success cancer treatment has had over the last 20 years, this only serves to highlight the need for us not to give up trying to improve our therapies. If we persevere, the breakthroughs will come.
In the vast majority of cases, improvement in outcomes occur in small, incremental steps. These small improvements are nevertheless real and highly relevant for our patients.
Furthermore, as doctors, we must be careful not to pass value judgements onto our patients. A month can seem like a short time for someone who has decades to live, but it can be a significant and precious opportunity for someone faced with a terminal condition – precious time to put a household in order, precious time to say goodbye to loved ones, precious time to make peace with God.
We also urge the reader to remember that chemotherapy, either on its own (eg in germ cell tumours, ovarian cancer, lymphoma, leukaemia) or in combination with radiotherapy (eg in cancers of the mouth and throat, cervical cancer), is able to cure cancer.
Even when the cancer is in its most advanced stage (metastatic or Stage 4), chemotherapy can still play an important role, not only to prolong life, but to improve quality of remaining life.
For instance, in colon (or large bowel) cancer where disease has spread (eg to the liver or lung), the average survival before the widespread use of chemotherapy was approximately six months, with virtually zero prospect of cure.
With the step-wise advance in chemotherapy, we can now expect average survival periods of 24 months [Annals of Oncology, 2010; 21 (suppl 5): v93-v97].
Even more encouragingly, in a small number of patients, although the cancer may have spread (albeit to a limited number of sites), chemotherapy, in combination with surgery or radiotherapy, can actually eradicate the disease, leading to long-term survival of many, many years, and even cure.
This highlights the need for patients not to delay seeing a consultant oncologist because the earlier the disease is detected, the better one’s chances are.
We do live in a world where statistics matter. Our colleague, Dr Albert Lim, has highlighted this in his articles - Thinking numbers (Fit4Life, February 26, 2012) and Living in a probabilistic world (Fit4Life, July 31, 2011).
Clinical guidelines that influence our practice are based on the statistics derived from well-designed trials.
No oncologist can claim that all patients will invariably benefit from chemotherapy, but we can give good, informed advice to our patients, based on very thorough and careful analysis of these statistics to stack the odds in their favour.
Dr Amir alludes to the “bevacizumab story”, a drug being initially approved and then withdrawn as a result of subsequent trials refuting its effectiveness, as a negative point.
On the contrary, it highlights the success of the stringent standards applied to licensed medication, and the absolute seriousness with which regulators view what can be recommended for human consumption.
It can only be achieved via multiple trials on thousands of patients, and hundreds of doctors toiling thousands of man-hours examining patients and recording the effects of the drugs, so that we can have a reliable body of evidence to say Drug A truly is effective for cancer.
Contrast this to unregulated or unlicensed products, where vested interests and commercial concerns abound. Where is the evidence that Herb A or Supplement B is truly any better than a placebo or “sugar pill” at the end of the day? What about the consistency of the manufacturing process, quality assurance of ingredients, or batch control?
How are these products tested to ensure active ingredients are present in the required concentrations, and harmful toxins are excluded? Where is the regulation and accountability for the manufacturer or prescribing physician, especially when something goes wrong?
These questions need to be answered.
Worse, we know that some nutritional supplements can actually enhance cancer growth. For example, in certain types of breast cancer where growth is promoted by oestrogen, patients may make the detrimental error in consuming supplements high in plant phyto-estrogens, thus stimulating the growth of the tumour.
Another example is supplements that interact and reduce the effectiveness of prescribed medication. The Star recently reported that two traditional medicinal products have been found to be harmful and subsequently banned by the Health Ministry. So let us get rid ourselves of the notion that herbal or traditional medications are all good and without side effects.
Dr Amir’s article cites that for some nutritional supplements, laboratory tests have confirmed that they kill cancer cells in petri dishes and laboratory animals, and this is evidence to proceed in humans.
This is not the case. There are thousands of chemicals shown to kill cancer cells in the laboratory, but after rigorous testing, only a handful are suitable for subsequent human trials.
The concept of “boosting one’s immunity” is always touted to be the benefit of taking nutritional supplements. Whilst the notion behind this is laudable, the burden clearly rests on nutritional supplement advocates to provide convincing evidence, which is lacking.
Secondly, harnessing the immune system to fight cancer is by no means a novel concept, nor the preserve of nutritionalists or herbalists. The field of oncology is already investing billions into immunotherapy, and the results are promising with drugs such as ipilimumab [New England Journal of Medicine, 2011 Jun 30; 364(26): 2517-26] beginning to filter through.
We do accept that there may be potential benefits from nutritional therapy, and are fully supportive of conducting well designed clinical trials to ascertain benefits and document side effects. But to state that nutritional therapy is the future of cancer treatment is a statement of faith, rather than of fact, and at worst, may lead to false hope and eventually delayed or ineffective treatment.
In the final analysis, we encourage all patients faced with the prospect of a journey with cancer to speak to a fully-trained consultant oncologist or members of reputable cancer societies (eg the Malaysian Oncological Society) to discuss their options.
We strongly discourage patients from making critical decisions about their health and well-being based on unreliable sources of information. No matter how well-meaning, without proper oncology and scientific training, any interpretation of evidence for chemotherapy can be taken out of context.
Both Dr Tho Lye Mun and Dr Daniel Wong Wai Yan are consultant oncologists.