Team:ETH Zurich/Practices/Medicine
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Medicine
Introduction
Talk with Dr. MD Heinz Läubli from Universitätsspital Basel
How useful would it be to have an early detection of metastasis or cancer?
It depends on where the cancer comes from, especially if there is metastasis. The device would be useful if it leads to a better treatment. In patients with a localized tumor we would be able to use systemic therapy, like chemotherapy. Chemotherapy is used when the tumor cells are already disseminated.
Currently there is a device called Cell Search for detecting cancer. Are you using it?
No, we are not using it. In the last 10 years there has been many publications about secreted tumour cells, but it is still not completely standardized and it is not clear whether it is meaningful. You would need to talk with a pathologist about that. In Switzerland it is not used clinically and probably nowhere in the world.
Do you think it will be useful to treat residual illness (such as CTCs) after a treatment in a patient if they are not showing any metastasis?
The treatment would be useful in a biological sense, as it shows presence of residual disease, but to know if it is in a medical sense we need a clinical trial. Some studies have shown that healthy people also present CTCs, and no trial has shown whether it is useful to treat only if CTCs are present. However, if this is proved, it would be very useful to treat the disease while it is still possible.
How do you usually detect cancer? Which stages is it usually found in?
Patients are usually diagnosed during emergency situations: they either come with a pneumonia or another derived problem, or their family doctor sent them. When the patient arrives to oncology department, they have already done a biopsy. This is the best for the patient, as it is less disturbing than being referred immediately to oncology. The stage of detection depends on the screening method and the symptoms. By screening we can detect cancer in early stage. In many cantons the screenings are not covered by the insurance but they are highly recommended. However, this is not possible for all cancers. For instance, for lung cancer there is no screening and many patients come later to the doctor because of their lifestyle (eg. smokers). In these cases we unfortunately cannot help the patient. It depends on the organ and if there symptoms. For example, if there is disturbance of the sight, it is easily detected because the patient will consult immediately the doctor, but for symptoms concerning the intestines, it is harder to diagnose. We have some screening methods for colon cancer and at certain age colonoscopy is recommended.
Do you test the predisposition of the patients to have cancer with DNA tests?
It depends. If we have a woman of 28-30 years old with breast cancer we will certainly do a genetic test for BRCA1 and BRCA2. For a woman with 55-60 years old with no big family history of cancer, no. Currently much is decided with scores of how many relatives with cancer a patient has, and then we decide whether to make the test according to that. Genetic testing has advanced quite quickly, and with next generation sequencing we can do this tests quickly in pathology, so we can see if there is any punctual mutation that we can target in about 40 genes. Now we can detect a 2% of mutated cells from a tumor sample, which is not bad. In the future many more than this 40 genes will be analysed and we have to learn what to do with this information.
What do you think is worse: to have a false positive or a false negative?
Well... (laughs) A false positive can have a big impact on the psychological level and it’s very stressful for the patient, so it depends on the consequence of a positive test. If you can improve the treatment then it’s ok and you can accept the psychological impact. It’s the same with tumor markers, like CA23-29 for breast cancer. There are no trials that show that it’s useful to measure them and they might be stressful for many patients. It is also not nice to say your patient: “look, you have CTC but we don’t know what it means”. We need to do some trials first and also some counseling for the patients with this type of tests.
How many tests do you usually perform before you confirm that a patient has cancer?
Usually with a biopsy and an histology it is sufficient, especially if the pathologist says that there is invasive growth. Then, histochemistry will show the type of cancer. We can do a DNA test to find punctual mutations.
Our device requires of a period of incubation of the blood sample, before introducing it into the chip (4-5h). Do you think it would be possible to implement it in the clinics? Would it require trained staff?
Probably trained staff will be required in the lab. You can go to the hematology department of the hospital where you want to implement the test, as they are the most experienced with blood sample preparation.