Does surgery help patients with asbestos-related cancer?
By Clare S Ryan, on 9 February 2012
When the link between asbestos and lung disease, and a previously rare cancer called mesothelioma, was first recognised in the early 1980s, doctors quickly realised that they were going to see a dramatic increase in the number of cases over the coming decades.*
As doctors, they wanted to find the most effective treatment, and duly started implementing the therapy that they knew best – surgery in combination with chemotherapy.
However, in the recent Lunch Hour Lecture, ‘Cutting to cure cancer and ‘the limits set by nature’’, Professor Tom Treasure asked the uncomfortable question: is there any evidence that nearly 30 years of performing radical surgery has helped patients?
Professor Treasure, a cardiothoracic surgeon from UCL’s Clinical Operational Research Unit, started to answer this question by looking at patients whose primary cancer was in the lining of the lungs, known as ‘mesothelioma’.
An initial review of the existing literature describing outcomes of patients who had had surgery to remove mesothelioma tumors found very limited data, much of which was anecdotal.
On the basis of their literature review, Professor Treasure and colleagues from Guy’s and St Thomas’ Hospital decided to conduct a randomised control trial to assess the survival outcomes of patients who had had mesothelioma surgery, versus those who hadn’t.
Surprisingly, considering how common it is to have surgery to combat the cancer, the study (which was published in the journal Lancet Oncology in 2011) concluded that surgery “offers no benefit and possibly harms patients”.
After that bombshell, Professor Treasure paused to consider why it was that doctors, who we assume have their patients’ best interests at heart, had taken so long to come to this conclusion. Why didn’t (or couldn’t) they see the bigger picture?
Interestingly, Professor Treasure found that fiction was often more insightful than the medical profession. In the novel, So much for that by Lionel Shriver (author of the bestseller, We need to talk about Kevin), the main character spends close to a million dollars on treating their lung cancer.
By the end, the protagonist’s doctor says that the therapy has lengthened her life by a good three months, to which the patient’ s husband comments “but they were not a good three months”.
Professor Treasure’s lecture moved on to look at secondary lung cancer, which occurs when a cancer that first appeared in one part of the body spreads, or ‘metastasises’, to the lungs. Does surgery help in these cases?
The short answer to this question is that doctors don’t know yet. Again, previous data about cancer surgery seems to be flawed.
Studies have looked at survival rates in patients who received surgery for secondary lung cancer, and concluded that the survival rate is about 40%. However, the huge majority of these studies seemed to have assumed that without the surgery the survival rate was nil.
Professor Treasure explained that it is impossible to tell from these kinds of studies whether the 40% survival rate was a result of the surgery, or a feature of the patients who had been selected for surgery – who may have had a greater chance of survival in any case.
Without a large randomised control trial, which is now taking place, it is impossible for doctors to see the true picture as they’re blinded by all the variation in their individual patients.
Professor Treasure was excellent at setting his story in context, recognising that doctors, like other scientists, have not reached the limits of knowledge in their profession, and have often been proved wrong throughout the course of the history of medicine.
He also recognised that it is very hard for doctors (and even harder for patients) to accept that doing more may not be better than doing less. We need solid evidence about the efficacy of treatment in order to give the best advice for a disease as complicated as cancer.
Professor Treasure’s extremely clear and thought-provoking lecture ended with a plea. In order to conduct studies to inform the future of medicine, doctors desperately need patients to take part in randomised trials. The outcome may, as demonstrated in this lecture, be unexpected.
Image: Roberto Mayer, UCL
*Note to readers: the headline and first paragraph of this post were altered on 11 February 2012 to emphasise that this lecture relates to the cancer mesothelioma, and not lung cancer.