Cancer on my mind is an article written by Dr. Albert Lim Kok Hooi, a consultant oncologist. He opens his article by saying:
As a doctor, I am interested in how the human mind works. As an oncologist, I am interested in the lure of alternative medicine. And so I have tried to understand why, in spite of all the scientific evidence at hand, there are many amongst us who do not want to undergo conventional cancer treatment – surgery, radiotherapy, chemotherapy and targeted therapy – but instead risk being treated by unproven and potentially dangerous alternative therapies.
He goes on to say that this happens because sometimes science is not very well understood. He talks about confirmed bias, a phenomenon in cognitive science, the science of how the mind works. He describes it as a person that -- notices the hits and ignores the misses in support of his own beliefs. So, basically someone might have a strong bias against chemotherapy, for no other reason than what they have seen on television, without really knowing the true facts.
He talks about evidence, what is evidence and what is not. Take for instance anecdotes, someone tells someone else a story about cancer survival because of a certain herb. Its not very long until its the next cure for cancer. Dr. Albert feels that anecdotal evidence is the weakest level of evidence in science.
Dr. Albert stresses that the only way to know if a something works is to rely on a randomized clinical trial (RTC). I think what the oncologist has to say next is important.
We are all unique. What works in one person may not work in another. What works in a subset of patients with a certain disease may not work in another. The first step in a R.C.T. is to select the group of patients we want to test a certain treatment on.
I give an example. Early colorectal cancer is treated by surgery. The cancer has not (apparently) spread to other parts of the body, based on x-rays and other imaging examinations. But the cancer will recur in a significant proportion of patients.
We want to know if by adding a new drug, oxaliplatin, there will be fewer patients who suffer a recurrence.
We randomly assign over a thousand patients to the conventional two drugs treatment (5-FU And Leucovorin) and a thousand more to the new three drugs combination (oxaliplatin, 5-FU and Leucovorin).
We carry out very complicated statistical calculations on how these two groups of patients will fare in the coming years.
Finally we reach the conclusion that the three-drug combination cures more patients.
Thousands of clinical trials are done in a similar way to test hundreds of drugs in scores of clinical scenarios. This is all very laborious and expensive. But what choice do we have?
The answer is – none at all.
The R.C.T., however complicated and tortuous it may seem to many people, is the only way to prove a treatment works. Trials like these generate new treatment regimes that cure more and more cancer patients every year.
Our subjective biases are no substitute for objective research when it comes to treating cancer.
1. The use of clinical trials to establish prescribing guidelines for evidence-based medicine is highly criticized because such trials have little relevance for the individual patient in the real world, the individuality and uniqueness of each patient.
The sample of participants in a randomized controlled trial is typically drawn from those deemed most likely to benefit from the protocol. It usually excludes the very young or old, the non-compliant, and those with co-existing illness.
In clinical trials, many patients are excluded because they could not complete the rather arduous treatment. So randomized comparisons are of healthier treated patients against all the controls, rendering a lot of trials invalid.
While the evidence obtained from the clinical trial may apply to the sample of trial participants, it may have little relevance for the individual patient in the real world.
There is no proof beyond reasonable doubt for any approach to treating advanced cancer today. There is only the bias of clinical investigators as a group and as individuals.
Whatever clinical response that has resulted to the average number of patients in a randomized trial, is no indication of what will happen to an individual at any particular time.
They are trying to identify the "best guess" treatment for the average patient. You cannot mate notoriously heterogeneous diseases into "one-size-fits-all" treatments.
Posted at 12:54PM on Jul 5th 2007 by Gregory D. Pawelski