New research emanating from the US has sparked fresh debate about whether certain forms of cancer should be classified as cancers at all.
The issue has been raised by a working group of America's National Cancer Institute and its findings were published last week in the Journal of the American Medical Association.
The backdrop to this research concerns the emphasis that is placed on the early diagnosis of cancer and the inherent screening processes that are involved in its detection.
The researchers argue the diagnosis of certain "cancers" ought to be reclassified, as they do not pose a substantial risk to the patient, who will – in some cases – nonetheless seek aggressive treatment upon hearing the word "cancer".
Lethal process
"The word 'cancer' often invokes the spectre of an inexorably lethal process," writes Dr Laura J Esserman, lead author of the report in the Journal of the American Medical Association and director of the Carol Franc Buck Breast Care Centre at the University of California, San Francisco.
She contends that cancers are diverse and can follow “multiple paths”, not all of which lead to death or the spread of the disease to other parts of the body.
Screenings for breast and prostate cancers in particular “appear to detect more cancers that are potentially clinically insignificant”.
HSE National Cancer Control Programme director Dr Susan O'Reilly told The Irish Times she agrees with these assertions and pointed to a need for international pathologists to come together and decide on new terminology.
“We need to agree on some terminology that makes sense, like ‘a lesion of low malignant potential’,” she says. “We might need to get away from the scary word ‘cancer’ because when patients get these pretty harmless things diagnosed, they are often just as panic-stricken as someone who has been told really bad news.”
Esserman says the use of the term “cancer” should be reserved for describing lesions with “a reasonable likelihood of lethal progression” if left untreated. The research claims the detection of a tumour that progresses at a slow rate is “potentially harmful” because it can result in “over-treatment”.
Over-diagnosis
Esserman describes the problem of "over-diagnosis"; when tumours are detected, that if left unattended, would not become clinically apparent or cause death. "Over-diagnosis, if not recognised, generally leads to over-treatment," she says.
O’Reilly takes issue with the term “over-diagnosis” – pointing out that when somebody is tested for cancer and an abnormality materialises, something has been found. “It’s not an over-diagnosis – it’s a diagnosis of something,” she says.
“If there is a risk of say 10 per cent over the next five to 10 years you’re going to get an invasive cancer in your breast, some women will say, ‘I’m not living with that, I want those breasts off,’ while others will say, ‘That doesn’t sound too bad, I’ll leave these alone.’
“Either one of those options is reasonable, so it’s not necessarily ‘over-treatment’. It’s trying to tease out the options and not pushing treatment if the benefits are very small. What is happening is we are finding these early lesions and then there is a lot of debate as to what is the best strategy to deal with them.
“The patient will hear then if it is a low- risk situation, or that it’s not a big worry but has the potential to turn nasty, and to some degree then the patient’s tolerance of risk and individual perspective comes into play.
“Some patients will be quite happy to hear, ‘We don’t think you have to worry and we can watch you.’
Other patients will simply say, ‘I cannot live with the anxiety of a certain small risk this will turn into a full blown cancer so I’d much rather have major therapy or my breast removed so I don’t have to think about it.’
"It's about making the patient understand what the level of risk there is or isn't and what their options are. The message for patients is don't be frightened of screening and get all the information you need. The doctors in Ireland are very knowledgeable about this."
Screening programmes
The Irish Cancer Society's chief executive, John McCormack, says there is some discussion with regard to screening "where you are detecting cancers which if you didn't find in a screening programme, they wouldn't do harm".
“When you set out to do mass-population screening, you have to be very careful that you’re not doing more harm than good, and that is very important.
“We’d have no doubt the screening programmes we have in Ireland at the moment are genuinely finding lesions that, if you didn’t discover in a screening programme, would go on to cause problems.”
With regard to the risks associated with certain “cancers”, the researchers talk about recognising cancer as not one disease, but a number of different diseases so clinicians can “individualise” treatment.
Cancer screening should be “adapted with a focus on identifying and treating those conditions most likely associated with morbidity and mortality”.
The researchers also say the ability to design better screening programmes will depend on studying the disease and its behaviour over time to ascertain whether it will be aggressive or slow moving.
Different cancers
O'Reilly says clinicians' ability to "assimilate the behaviour of different cancers or premalignant cancers, which are fairly harmless, is getting better and better all the time".
“We would hope that in a few years, we will have genetic fingerprints of early pre-malignant cancers that will tell us reasonably safely whether they’re going to be pretty harmless or pretty nasty,” she adds.
This was echoed by the Irish Cancer Society, with McCormack talking about "a big push towards targeted therapies".
“These are developed based on the particular genetic make-up of your particular cancer and that allows us to develop more powerful therapies. The challenge with therapies at the moment – things like chemotherapy – is that they affect every cell in the body.
“The benefit of having a targeted therapy is it just targets the actual cancer cells with a more powerful dose and they are more effective overall.”
