Cancer staging, or description of the anatomic stage of the disease, is a very important part of our vocabulary in cancer. It’s a measure of extent of disease, it’s been present for many, many decades. The most common classification is the TNM classification that’s been around for sixty plus years and it undergoes revisions. Extent of disease by stage is the first indication that your screening programmes, early detection programmes, work or access to care is improving. You start seeing the profile of patients who are being treated shifting to those with early stage disease, with less extensive disease so it’s a very useful measure for healthcare systems to look at improvements. To do that you need to have a record of extent of disease in cancer registries and many cancer registries in developing countries now include stage in their descriptions of cases that they record.
However, the TNM classification is complicated and the new cancer registries that are being developed in low and middle income countries probably don’t have resources to record the details of TNM. It’s also probably not that important in those jurisdictions to record the very minor variations in disease extent. Basically what you’d like to know is how many patients present with metastatic disease, stage 4 disease, how many patients present with localised disease and how many patients have the rest extensive disease.
So in concert with IARC, an International Association for Cancer Registries, we have developed what we called Essential TNM and it’s basically recording who has metastatic disease, who has early localised disease and the rest middle group who has locally extensive disease. But we mapped it out on TNM almost like a telescopic ramification so if you become a more sophisticated cancer registry and you want to record TNM, you can. If you want to then analyse by the Essential TNM you can collapse the elements into Essential TNM. So, this is a very flexible and nimble classification, it has been pre-tested in a number of countries in Africa. We hope that IARC will introduce the education on this new classification into their GICR project which is the Global Initiative on Cancer Registration which tries to scale-up the number of cancer registries in low and middle income countries. We thought it was a great opportunity to actually leapfrog and include extent of disease in those registries.
What can clinicians do to improve best practice?
I think that most of us, most of clinicians, know exactly the extent of disease when they treat patients, they must otherwise you cannot prescribe treatment. But if you don’t write it down then there’s no record and nobody can analyse it. We asked, many years ago we did a consultation on cancer staging in Canada, we did a survey and we asked clinicians if the cancer stage was included in cancer registries would they be more motivated to writing it down and they said definitely. Because somebody would actually, other than them, use the information.
How can people get involved?
We tested it, piloted it in the African cancer registries. I think that IARC is going to introduce it through their GICR project because it still needs education. So I think that people who are interested in it should contact the International Association of Cancer Registries of IARC.