Digital pathology can give a better prognosis
Prostate cancer is a difficult form of cancer for pathologists to assess. A new support system for decision-making can give more accurate prognoses and thus help to avoid unnecessary surgery.
Pathologists have a vital occupation. One of their tasks is to examine tissue samples to see whether a patient has cancer and, if so, its degree of severity. The assessment made by the pathologist then serves as a critical piece of data for deciding whether the patient is to be treated and, if so, how.
Such assessments rely upon the pathologist’s knowledge and accumulated experience. Quite often, however, different pathologists arrive at different results. Prostate cancer is one of the kinds of cancer which is difficult to assess.
“If you show two pathologists the same samples, they only agree in 60-70% of the cases,” says Ingrid Carlbom, guest professor at the Department of Information Technology.
Along with her colleague Christophe Avenel and pathology researchers, Ingrid Carlbom is developing a digital support system for making prognoses in prostate cancer cases. When it is up and running, the system, CADESS, will help pathologists to analyse tissue samples and point to where the abnormalities are. The system can also indicate the severity of the cancer. The advantages of a system like CADESS are many. The aim is to remove the subjective elements of the assessment as far as is possible and thus make it safer for the patient.
“A better assessment can help reduce the number of unnecessary treatments – those which do not help the patient to live longer but which do have distressing side effects. Only 10-15% of newly discovered prostate cancer needs treating. The remainder has slow growth and is not life-threatening,” says Christer Busch, pathologist and senior professor at the Department of Surgical Sciences, who is collaborating with the IT researchers.
It also saves time. Pathologists are already in short supply and the average age of those currently working is high. “Using the support system means that assessments which now take an hour can be carried out in five minutes,” says Ingrid Carlbom.
“Our intention is not to replace pathologists,” she points out, adding that the system is intended to support decision-making.
Put simply, it can be said that researchers use two different methods to ‘train’ their cancer-recognition algorithm. Firstly, the research team uses samples from a large group of patients where it is known how things went for them.
Secondly, they use a group of experts containing 13 internationally eminent pathologists who together provide expert statements regarding patterns found in the tissue samples. This group also has a second important purpose: They help the system to be accepted by pathologists.
FACTS: Prostate cancer
This is the most commonly occurring form of cancer in Sweden. It mostly affects older men. Approximately half are over 70 and only a few are under 40 when diagnosed. There are many different kinds of prostate cancer which are dealt with in different ways. Some grow slowly and do not become life-threatening. Others are aggressive and need treatment. Assessment and prognosis is carried out using the Gleason Scale which grades the cells on a scale from one to five, where five is the most serious category of cancer.