Finding tumor markers: tests make sense if they actually serve

Immediately clear the field of a bad habit that some doctors have: to prescribe to a patient, who has various and vague disorders, perhaps aged, looking, in the blood, for certain "clbadic" tumor markers "Such as alpha-fetus protein, carcinoembryonic antigen (Cea) or other proteins such as CA 125 or Ca 19-9, just to see if there is a tumor. These proteins, indeed, may be a sign of cancer, but they are nonspecific, in that they also increase as a result of other diseases, especially inflammatory ones. Thus, for an early diagnosis, they are not significant and lead to useless, unnecessary and costly diagnoses for the patient. "These markers – explains Giuseppe Curigliano, director of new drug development for innovative therapies of the European Institute of Oncology in Milan – are, on the contrary, helpful in monitoring the disease when a patient is already in therapy: for example, Ca125 is important in ovarian cancer, the alpha-fetal protein in that of the liver and also in that of the testis. "

Identify the" cancer risk "

The question remains: is it possible, thanks to identifiable biomarkers with a test, to identify the "cancer risk" in a person? A complicated theme that we try to simplify. There are then two opportunities. The first is the ability to identify people genetically predisposed to cancer. For the moment, this concerns the famous "Jolie genes", in the abbreviation Brca1 and Brca2. The presence of these genes in the DNA of a person (who is generally familiar with cancer) indicates the risk of developing bad and ovarian tumors (but it is discovered that these genes are also related to other tumors such as prostate). And that is why the American actress Angelina Jolie, carrier of these genes, first underwent a mastectomy and then ablation of the ovaries. The second is to exploit biomarkers to diagnose the disease in a very early stage and therefore treat it with survival benefits.

The risk of "false positives"

And here the theme of prostate cancer mastering with the Psa test, the specific prostate antigen, on the blood. At first, the presence of high values ​​of Psa suggested a rather aggressive attitude: the intervention with ablation of the gland that could have consequences of various kinds, including those that have to do with it. badual activity. Now we are more cautious. "PSA is not specific for a tumor – says Gabriella Sozzi, director of the complex structure of tumor genomics at the Milan Cancer Institute. It can also increase in the case of prostatitis (that is to say an inflammation of the prostate, ndr ). That's why he has raised so much discussion. And a less aggressive attitude towards the interventions. "On this subject, the American specialists are more demanding than the Europeans because they think that the test contains too many" false positives ": in other words, too much often the test indicates a risk of cancer whereas there is none and opts for a vigilant approach active waiting or monitoring, that is to say the follow-up of the subject continues to be the subject of discussion – in short, the so-called "evidence-based medicine" which, based on the scientific evidence that should certify the quality of therapies and interventions, must be put into play from time to time. And not always what was true yesterday, it is also today.

Screening is fundamental

The future speaks of "liquid biopsies", that is to say blood tests, able to intercept the first signs of the presence of a tumor (thanks to the identification of the genetic material that cancer cells release into the bloodstream). But in the meantime, we must not forget the value of old, if not very old, tests for early diagnosis. We are talking about occult blood in the stool, always a "must" for the prevention of colon cancer. And this in Italy is offered to the population in the screening programs promoted by many Italian regions. Or the Pap test, for cancer of the cervix of the uterus. Today's test badociated with HPV research, the papillomavirus, the origin of cervical cancer of the uterus. Not to mention the mammogram for bad cancer, which does not yet reach all women in Italy, or the Tac spiral, suggested by some to smokers.