The case for increased screening: Canadian CT scanning
Alberta Health Services plans to significantly increase the number of PET/CT scans being undertaken in the province. Dr Chris Molnar talks to Nic Paton about the organisation’s intention, and what this means for the future of scanning and diagnosis.
At first glance, it would perhaps not be surprising to hear that a few eyebrows were raised among radiologists and radiographers by Canada's Alberta Health Services' (AHS) November announcement that it was intending to treble the number of positron emission tomography/computed tomography (PET/CT) scans performed in Calgary.
After all, it was not too long ago - early in 2011 in fact - that the British Medical Association (BMA) was making noises about the 'worried well' - those who pester doctors with minor ailments, or have the money or insurance to pay for regular, and often unnecessary, tests and screening.
Such excessive screening, the BMA argued, was not only often a waste of money for health services, but also potentially had significant adverse effects in terms of radiation doses for patients. An additional problem of such screening is that it is often not contextualised. Abnormalities may be spotted, which, although not significant, may lead to unnecessary worry, and further referrals and investigations having to be carried out.
As Professor Vivienne Nathanson, director of professional activities at the BMA, encapsulated it at the time: "If you have a lot of people having CT scans that are picking up abnormal variations, then you have to start spending a lot of time chasing up tests that are unnecessary, and cost money and resources. This can cause a lot of stress for the patient."
However, put this point to Dr Chris Molnar, zonal division chief for nuclear medicine for AHS, Calgary, and it becomes very clear what is being promoted in Alberta is a world away from these concerns. "The key first point to make is that this is not about screening, it is not health promotion. Our public health system is paying for this, so it is not about private companies screening people unnecessarily," she emphasises.
The point in this context is that this is something for patients who are already sick and, as it were, 'in the system'. "We definitely do not support screening of asymptomatic patients," she explains. "The high radiation dose is similar to a full diagnostic CT and that is an unacceptably high dose for screening. It is also, of course, costly.
"So we have very strict criteria for accepting patients. They have to have a diagnosis of malignancy, or for it to be highly suspected because of other anatomical investigations. What is changing is the increased access for these sorts of patients," she adds.
PET/CT scanning combines two complementary technologies to create full-body imaging, and has become a vital weapon in the physicians' armoury when it comes to diagnosing and managing a range of conditions, including neurological and cardiovascular disease, but primarily cancer.
While the CT scan can pinpoint the size, shape and location of abnormalities in the body, the PET scan can show additional cancer sites not readily visible on CT, or may show that an abnormality is benign rather than malignant.
The results of such scanning, AHS has estimated, can change the course of treatment in as many as a third of cancer cases, and, in the process, help avoid unnecessary surgery, radiation treatment and chemotherapy. Moreover, after treatment, PET/CT can detect scarring and residual cancer that may require additional treatment.
As Molnar puts it: "There are, of course, standards of practice in place for different types of cancer, standards of care that have been established for, say, lung, oesophageal, and head and neck cancer, and so on, but there are still a significant percentage of cases that elicit surprise discoveries.
"We find that 30% of cases have unexpected findings in relation to the disease. It may be that it has metastasised already and that changes things quite a lot, for example. So what we wanted to achieve was imaging that could help us to tailor the specific treatment to the patient much better.
"This fits in, too, with the emerging trend of practice being ever-more tailored to the patient. So you can get molecular therapy that targets specific cells, for example," she adds.
Two of the key drivers for this change were the fact that lung, oesophageal, and head and neck cancer patients often had to wait six to eight weeks for a scan, rather than the two that is preferred.
"This was just not acceptable. There was also more surgery taking place than was needed. So the main driver was simply pushing for easier access," says Molnar. "What increasing scanning capacity in this way is very good for is showing how patients are responding to therapy. There is also often not enough follow-up imaging for recurrent cancers, which this will help to address.
"Patients with, say, pelvic cancer can have radiation for their prostate or for cervical cancer yet then get colorectal cancer. Those patients need to be assessed, which this programme should help."
While this announcement, then, is clearly good news for Albertans, Molnar is careful not to over-exaggerate the innovativeness of what AHS is doing. In actual fact, although tripling any scanning programme is a significant step, in the context of the rest of the country it is, if anything, just bringing Albertans into line with the frequency of scanning elsewhere, especially given the fact that, in the past, Canada itself has been accused of lagging behind other developed economies with regard to access to PET scanning capacity.
"When it comes to scan rates in Canada, in Alberta we now have a scanner for approximately every 1.3 million people. When we get our second scanner in April it will be one per 0.94 million. In Saskatchewan it is one per 0.4 million and Manitoba it is one per 1.2 million, Ontario nine per 1.46 million and Quebec, the best of all, 13 per 0.6 million," explains Molnar.
"So, in many respects, what we are doing is not revolutionary, it's just what any other hospital would want to do - achieve the best standards of care that we can for our patients."
Effect on the front line
One of the most significant ramifications of this move, of course, is the effect it will have on radiographers, radiologists and support staff. Accelerating scanning programmes in the way AHS is trying to do inevitably requires careful workforce, workload and throughput planning if bottlenecks are to be avoided, and staff stress and workload levels managed.
"It has definitely had a knock-on effect in terms of shifts and workload. We have had to add an evening shift. We have increased our numbers from 2,180 to 3,450 a year just by adding and doubling our evening shift. The second scanner from April will bring us up to 5,500 a year so it will increase still further," says Molnar.
"We have also had to hire more technicians. We now have a dedicated evening shift technologist and have had to change some of the rotations. We have a fairly big nuclear medicine department, so people are able to rotate through the PET/CT area pretty easily to provide uniform coverage. We have also reworked the technician workflow, and have had to hire some more reception staff," she adds.
So, what are the benefits of raising the scanning bar in this way?
"First of all there is a saving for the patient, primarily because we are giving them a better diagnosis. We are doing a better job for the patient, that is the number one priority," emphasises Molnar. "But, at the same time, it has to be remembered that there is a cost saving. The cost of hospitalisation related to procedures that are not necessarily going to benefit the patient is obviously a waste.
"With chemotherapy, if it is not working then to continue to give a full course is not only financially poor, but also bad for the patient, who has to continue with what will be an aggressive form of treatment," she contends. There is no better way to measure lymphoma, for example, than by CT and PET/CT imaging. It will show what tumour cells are responding to the chemotherapy right away.
"This capacity boost means improved cancer treatment decisions and individualised care pathways for more patients. We know that each cancer is different. The more we know about an individual's situation, and the earlier we have that information, the better the treatment options and outcomes will be," she adds.
"For the future, I can see this approach being used for patients with dementia. We are seeing significant numbers of dementia patients, so this could be useful. I can also see it being used for conditions such as osteomyelitis of the spine. We are not necessarily cutting edge on something like this; it is, if anything, about trying to catch up. But what it is, is a very positive process.
"Another great advantage is that you have both the anatomised and functional imaging, so in certain cases you may be able to lower costs by not having to do anatomical imagining," Molnar concludes.
This article was first published in our sister publication Medical Imaging Technology.