SOMETIMES NOT EVEN THE BIOPSY PROVIDES CERTAINTY

Although the biopsy is performed in order to achieve diagnostic certainty, the result sometimes does not clarify the picture. To people outside the world of medicine, this is not easy to understand and, naturally, causes annoyance, especially since the biopsy was performed because the 4 clinical dimensions of the diagnosis clearly indicated the possible presence of a tumor (HAVING A SURE DIAGNOSIS). This means that, after waiting for the biopsy material to be prepared and analyzed, the patient is told that “the biopsy doesn’t tell us anything”. How can this be? 

Depending on the strength of the evidence yielded by the 4 clinical dimensions before the biopsy was taken, this situation of “inconclusive results” may reflect 2 conditions.

1. The result may be a “false negative”, meaning that there is a tumor, but the biopsy has not confirmed it. This may, in turn, be caused by the fact that
   
   
   1. the nodule was so small and/or difficult to reach that the operator failed to sample it adequately; indeed, not always does the operator manage to take a representative sample of the tumor.
   2. the sample was taken from an area of the tumor that did not contain tumor cells; indeed, we should remember that a tumor nodule is made up not only of tumor cells, but also of inflammatory cells, immune cells, connective tissue, etc. In some tumors, such as those of the pancreas, the ratio of tumor cells to non-tumor cells may be as high as 1/100!
2. The result may be a “true negative”, meaning that, despite strong suspicion, there is, in reality, no tumor. In this case, the diagnostic suspicion is not confirmed by the biopsy. In such rare cases, the biopsy proves to be extremely useful; it dispels the strong suspicion of cancer and restores the patient’s serenity.

A false negative result is a source of frustration, as the problem of the diagnosis continues to prevent further decisions from being taken. In these cases, there are three possible courses of action: 

1. to repeat the biopsy, perhaps using more invasive techniques;
2. to wait and see how the situation evolves, trusting that time will tell. This is a slow and indirect way to exclude cancer; if the suspect mass grows over time, this proves that it is a tumor, and another biopsy can be performed; if it does not, we will continue to wait, trusting that the problem is not one of cancer.
3. to disregard the biopsy and begin anti-cancer therapy anyway, trusting that the 4 clinical dimensions  have aroused a sufficiently strong suspicion as to be “sure”. This approach may seem to be illogical and contradictory; indeed, if there were indications for a biopsy and this did not produce conclusive results, then it should be repeated. Well, yes and no; repeating the biopsy would involve further suffering for the patient and, especially, further delay.  

These are the complex situations that arise in oncology, and only the specialist can explain them case by case and take the best decisions, in agreement with patients and their loved ones.