These kinds of reports [Cancer Survival Victoria 2007] are only made possible by the dedicated workers within the Cancer Registry, and also all of the people who notify the cancer registry. It is a very important function: it is the tool for monitoring and evaluation and also a very useful tool for research.
What we measure is what we call relative survival: in this case the probability that a patient doesn't die from their cancer within five years.
Overall our five-year relative survival in Victoria in 2004 is 61%. So that means that 61% of patients diagnosed with cancer will not die from their cancer within five years. Now it is important to remember that that doesn't mean to say that 61% of them will still be alive five years after their diagnosis - that is not correct because cancer patients, just like everybody, are susceptible to dying from other causes, for example being run over by the proverbial bus. So what it's talking about is the actual effect of cancer on their likelihood of survival, and that's really what they want to know when they are diagnosed.
The most important take-home message from this picture really is that over the 20-year period that we have been monitoring, there has been a steady and encouraging improvement in survival in Victoria.
There is a better survival for women than for men, and that's true for just about all the individual cancers, for reasons that are not really clear. Older people are more likely to die from their cancer, than are the younger people. And again, the reasons for that are not very clear, except to say that obviously older people have a lot more co-morbidities that might affect their chances of surviving their cancer.
There is incredible diversity in five-year survival by different cancer sites, and you can see it varies from about 5% unfortunately for pancreatic cancer, all the way up to 99% for testicular cancer.
I want to talk a little bit about the Integrated Cancer Services regions. These are essentially consortia of public health services, although in some regions to a greater or lesser extent, there is a lot of active involvement with private providers as well. There is a little bit of variation from one region to the other. It is very hard to know why that might be, and in the absence of the kinds of data that would enable us to determine whether it is due to treatment or whether it is due to stage of diagnosis, it is very difficult to interpret. Here may be a clue: as most of you would know, Victoria has a very successful screening program for breast cancer called Breast Screen, and in fact it is a nationwide program, although we in Victoria like to think we do better than some other states, which I think is true. For breast cancer, where we've got screening, there is very little variation across the state: we think or we are confident in how far the cancer is advanced at the stage of diagnosis, there is very little difference in the survival. This suggests that women, regardless of where they are in Victoria, are treated almost identically for breast cancer, which is what we would expect.
Prostate cancer is an enigmatic tumour for those of us who work on it. There has been an incredible improvement in survival over time. This coincides with about a doubling or in fact a two-and-a-half fold increase in the incidence: that's the number of new cases of prostate cancer over the last 20 years, with a very, very small change in the long term mortality. What we are seeing is an enormous increase in the incidence, a very little change in mortality, which must mean that survival is increasing. This is largely because of the increase in the incidence, and a lot of those tumours that we are identifying today in the past would have never been identified during the man's lifetime.
Colon cancer is another one of our common sites. There has been a nice encouraging improvement in survival here. There have certainly been better treatments introduced over the time that we have been collecting this data, and there may well have been changes in early detection as well at the same time, although that is clear. Women seem to do better than men, and older age of diagnosis again for this common cancer is associated with worse survival.
For breast cancer, again we have seen a very encouraging improvement. We've certainly known over the period of these figures that there has been a change in early detection through screening which was introduced statewide in the early 1990s, so we would expect if screening is working that this would increase, survival would increase. At the same time there has also been dramatic change or improvements for therapy for breast cancer as well, so the two of them are combining together to produce much higher survival.
In terms of our very common tumours, lung cancer is the worst. There is very poor survival and very little change in survival over time. Basically for lung cancer, the cornerstone for control of lung cancer is prevention at the moment: that is really our best means to control the cancer.
Melanoma in Australia is a very common tumour, caused by excess sunlight, and you can see that it has got very high survival. So it is one of our most common tumours in terms of incidence, but not a very common cause of death, fortunately, because people who have it survive very well. There has been little change over time, but that is probably because we started from a very high base in the first place. And again, the phenomenon that you see almost everywhere else, that women do better than men and that older age at diagnosis is associated with poorer survival.
Associate Professor Dallas English is Deputy Director of the Cancer Epidemiology Centre
